Abst ract
Submitted: March 31, 2016 0RGL¿FDWLRQ2FWREHU Accepted: October 9, 2016
Local applicat ion of st at ins in t he
t reat m ent of experim ent al periodont al
disease in rat s
Obj ect ive: The obj ect ive of t his st udy was t o evaluat e t he local effect s
of st at ins as adj uvant s for t r eat m ent by scaling and r oot planing ( SRP) of
per iodont al disease induced in rat s. Mat er ial and Met hods: Ninet y rat s w er e
used in t he present experim ent . Periodont al disease was induced in all anim als
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of induct ion, t he bandage was r em oved and t he anim als w er e divided int o
t hr ee gr oups: 1) NT gr oup ( n= 30) , no t r eat m ent ; 2) SRP gr oup ( n= 30) :
SRP and ir r igat ion w it h cont r ol gel; 3) S gr oup ( n= 30) - SRP and ir r igat ion
w it h Sim vast at in. Ten anim als fr om each gr oup w er e eut hanized at 7, 15
and 30 days aft er t r eat m ent . Gingival biopsy specim ens w er e pr ocessed t o
analyze t he expression of m at rix m et alloprot einase 8 ( MMP- 8) . The m andibles
w er e r em oved and subm it t ed t o radiographic and laborat or y pr ocessing
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expr ession of MMP- 8 com par ed t o NT and SRP gr oups in all exper im ent al
per iods. I n t he radiographic and hist om et r ic analyses bet w een t he gr oups,
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SRP gr oups in all exper im ent al per iods. Conclusions: Wit hin t he lim it s of
t his st udy, it can be concluded t hat locally applied st at in was effect ive as an
adj uvant t r eat m ent for SRP in rat s w it h induced per iodont al disease.
Ke y w or ds: Per iodont it is. Alveolar bone loss. Sim vast at in.
Bianca Fernanda Espósito SANTOS1
Eduardo Quintão Manhanini SOUZA1
Maísa Ribeiro Pereira Lima
BRIGAGÃO3
Daniela Coelho de LIMA2
Leandro Araújo FERNANDES2
http://dx.doi.org/10.1590/1678-77572016-0149
1Universidade Federal de Alfenas, Faculdade de Odontologia, Alfenas, MG, Brasil.
2Universidade Federal de Alfenas, Faculdade de Odontologia, Departamento de Clínica e Cirurgia,
Alfenas, MG, Brasil.
3Universidade Federal de Alfenas, Faculdade de Odontologia, Departamento de Bioquímica, Alfenas,
MG, Brasil.
I nt r oduct ion
Per iodon t al disease ( PD) is a ch r on ic in f ect ion p r o d u ce d b y Gr a m - n e g a t i v e b a ct e r i a w i t h h i g h pr evalence levels2. I t occur s in gingiva in r esponse t o
bact er ial ant igens of dent al plaque, w hich accum ulat e
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gingivit is, charact erized by redness, swelling, recession and gum bleeding. I f not t r eat ed ear ly, it can pr ogr ess t o per iodont it is5.
Ty pe I an d I I I collagen s pr odu ced by bot h t h e
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t h e pr edom in an t com pon en t s of t h e per iodon t iu m ext racellular m at r ix. I nit ial cleavage of t he per iodont al ligam ent and gingival collagen is a key com ponent of t he act ive and pr ogr essive per iodont al lesions caused by int er st it ial collagenases, der ived fr om host cells8.
Enzym es called m at r ix m et allopr ot einases ( MMPs)
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in t he t oot h r oot , w hich allow s bot h apical m igrat ion and lat eral ex t ension of t he pouch epit helium . The clinical sequelae of t his pr ocess ar e t he pat hological incr ease in collagen dest r uct ion w it h t he inser t ion loss and for m at ion of per iodont al pocket s8.
According t o a st udy conduct ed in 199926, t he m at rix
m et allopr ot einase 8 ( MMP- 8) is t he m ain int er st it ial
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pat ient s wit h chronic periodont it is as well as in t he
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r epr esent ing 90- 95% of collagenolyt ic act ivit y am ong t he collagenases involved in t his pr ocess.
Tr eat m ent of per iodont al disease is based on t he elim in at ion of p at h og en ic su b g in g iv al m icr ob iot a b y sca l i n g a n d r o o t p l a n n i n g ( SRP)1 5. Ho w ev er,
m ech an ical t h er apy alon e m ay be u n su ccessfu l t o elim in at e pat h ogen ic bact er ia for t h ey ar e u su ally locat ed w it hin eit her soft or har d t issues, or even in areas t hat are inaccessible t o periodont al inst rum ent s, su ch as ar eas of f u r cat ion an d r oot depr ession s2.
D u e t o t h e s e l i m i t a t i o n s , s u p p o r t i n g m e t h o d s f o r co n v en t i o n al p er i o d o n t al t h er ap y h av e b een st udied7,27. Given t he pr om inent r ole of t he host as a
m ain dest r uct ion com ponent of soft and har d t issues seen in per iodont it is, t herapeut ic st rat egies, such as phar m acological agent s, have been highlight ed as a new t r eat m ent appr oach7,27.
St a t i n s a r e w i d e l y u se d d r u g s f o r l o w e r i n g cholest er ol; how ever, a bone for m at ion induct ion was obser ved not only in t issue cult ur es but also in m ice
and rat s2 0. That fact ar oused gr eat int er est in t he VFLHQWL¿FFRPPXQLW\E\FRQVLGHULQJWKHSRVVLELOLW\WKDW
t hese dr ugs could be used in bone diseases, such as per iodont al disease20.
Am on g t h e v ar iou s st at in s av ailab le, t h er e is Sim vast at in, w hich has been w idely used in clinical pr act ices t o con t r ol ch olest er ol lev els. Despit e, in ad d it ion t o it s lip id - low er in g f u n ct ion , t h is st at in i s n o t ab l e f o r o t h er si d e ef f ect s, i n cl u d i n g an t i
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pr oper t ies, besides t h e pr om ot ion of an giogen esis and incr eased differ ent iat ion of ost eoblast s, leading t o bone for m at ion20,27. These pr oper t ies pr ovide gr eat
pot ent ial for st at ins t o m odify t he cour se of chr onic
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diseases can be included.
Thus, t he aim of t his st udy was t o evaluat e t he local effect s of st at ins as an adj uvant t r eat m ent t o scaling and root planing of periodont al disease induced in rat s.
Mat er ial and m et hods
Anim als
This st udy was appr oved by t he Et hics Com m it t ee on Anim al Use ( CEUA) of t he Federal Univer sit y of Alfenas- MG - UNI FAL, follow ing t he st andar ds adopt ed by t he Brazilian College of Anim al Ex per im ent at ion ( COBEA) by num ber 605/ 2014. The sam ple size was det er m ined on a sam ple populat ion of 117 m ale rat s w it h an er r or m ar gin of 5% , het er ogeneit y of 50% and
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t he sam ple consist ed of 90 m ale rat s ( Rat t us norvegicus
albinus, Wist ar ) w eighing appr oxim at ely 200 t o 250 g,
w it h 2- 3 m ont hs of life, fr om t he Cent ral Vivar ium of t he Federal Univer sit y of Alfenas- MG - UNI FAL. They w er e kept under st andar d condit ions w it h wat er and food ad libit um , at r oom t em perat ur e and w it h a clear light / dar k cycle of 12 hour s.
Th e an im als w er e r an d om ized d iv id ed in t o gr oups accor ding t o a t able generat ed by a com put er pr ogram .
I nduct ion of exper im ent al per iodont it is
SP; Brazil) t o anim als up t o 225 g. For anim als bet ween 225 and 250 g, t he dose used was 0.18 m L/ k g of ket am ine hydr ochlor ide ( Rhobifar m a Phar m aceut ical I ndust ry Lt d.; Hort olândia; SP; Brazil) and 0.08 m L/ kg of xylazine hydr ochlor ide ( Rhobifar m a Phar m aceut ical I ndust r y Lt d.; Hor t olândia; SP; Brazil) . Wit h t he aid
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cot t on no. 10; Coat s Cor r ent e; São Paulo; SP; Brazil)
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and kept in posit ion by m eans of sur gical knot s13.
St udy design/ Local t r eat m ent
Aft er 7 days of induct ion and pr ogr ession of PD, t he ligat ur e was r em oved10. Then, t he anim als w er e
r an dom ized in t o t h r ee gr ou ps of 3 0 an im als each according t o t he following local t reat m ent s: 1) NT group ( n= 30) , no t r eat m ent ; 2) SRP gr oup ( n= 30) : SRP and ir r igat ion w it h cont r ol gel; 3) S gr oup ( n= 30) - SRP and ir r igat ion w it h Sim vast at in.
SRP pr ocedur es w er e per for m ed using 5/ 6 Mini - Five Gracey cur et t e ( Hu- Fr iedy Mfg. Cor porat ion, LLC; Chicago; USA) w it h t hr ee hor izont al m ovem ent s in t he fr ee faces in t he m esial- dist al dir ect ion; and t hr ee ver t ical m ovem ent s in t he int er pr oxim al faces in t he occlusal- cer vical dir ect ion9.
Nat r osol and Nat r osol+ Sim vast at in gel solut ions w er e slow ly pour ed int o t he per iodont al pocket in a single applicat ion using a syr inge ( 1 m L) and needle for insulin ( 13 m m x 0. 04 m m ) ( Bect on Dick inson I ndust r y Sur gical. Lt d.; Cur it iba; PR; Brazil) w it hout b ev el. Du r in g t h e t r eat m en t s, t h e or op h ar y n g eal r egion of each anim al was pr ot ect ed w it h a st er ile gauze, t her eby pr event ing t he int ake of any gels and pr event ing syst em ic act ion of Sim vast at in.
The st at in used was Sim vast at in ( Sandoz Brasil´ s Phar m aceut ical I ndust r y Lt d. ; Cam bé; PR; Brazil) , and it s pr eparat ion was car r ied out by dilut ing a 20-m g t ablet int o 20 20-m L of Nat r osol ( 20-m anufact ur ed by com pounding pharm acy Pim pinella Cosm et ics; Alfenas; MG; Brazil; LOGI N: 22394928/ 0001- 30) obt aining a
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Exper im ent al per iods
Ten anim als fr om each exper im ent al gr oup w er e eu t h a n i zed i n a ca r b o n d i ox i d e ch a m b er, w h i ch
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cent ral ner vous syst em and no r esidue in t he anim al. Eut hanasia was per for m ed at 7, 15 and 30 days post local t reat m ent s. Sam ples of gingival biopsies from t he
r egion w it h ligat ion w er e pr ocessed for biochem ical analy sis; t he j aw s w er e r em oved and sect ioned in halves t o be lat er subm it t ed t o bot h radiographic and laborat or y pr ocessing for hist om or phom et r ic analysis.
Cap pr eparat ion for conser vat ion of gingival
t issue sam ples
I n o r d er t o st o r e t h e sam p l es u n t i l t h e t i m e of an aly sis, a Tr is- HCl bu ffer w as pr epar ed in t h e biochem ist r y laborat or y of UNI FAL- MG, w eighing up 3.02 gram s of Tr is ( Hydr oxim et hyl am inom et hane –
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USA) , 5 . 8 5 gr am s of sodiu m ch lor ide ( Vet ec Fin e Chem icals Lt d.; Rio de Janeir o; RJ; Brazil) and 0.555 g of calcium chlor ide ( ACS Pr oquím icos - Trades of Chem icals; Sant a Mar ia; RS; Brazil) , in an analyt ical scale ( KERN & Sohn Gm bH; KERN GS 410- 3; Barlingen-Fr om m er n; Ger m any) .
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Milli- Q wat er ( Milipore- direct Q3 UV) , and it was t aken t o t he m agnet ic st irrer ( Fisat om - 115 V) wit h m agnet ic bar, pH m et er ( Digim ed - DM22) and t he t em perat ur e gauge ( Digim ed - DM 22) w it hin, adding hydr ochlor ic acid t o t he plast ic Past eur pipet t e t o r each pH 7.5 at
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Mili- Q wat er unt il t he m eniscus was r eached.
I t was necessar y t o include zinc t o t he Tr is- HCl buffer in order t o carry out t he sam ple analysis. Hence, 8.07x10- 4 zinc sulfat e ( Mer ck) w er e w eighed up in t he
analyt ical scale and added t o a solut ion of 100 m L of Tr is- HCl, w hich had been set aside in anot her beaker and t hen st ir r ed w it h a m agnet ic st ir r er using t he m agnet ic st ir bar. Wit h t he aid of a m icr opipet t e, 0.05 m icr olit er s of polyet hylene glycol ( Sigm a Aldr ich) was collect ed and slow ly added t o t he buffer st ir r ing so as not t o for m bubbles22.
Det er m inat ion of t ot al pr ot ein concent rat ion
Pr ot ein concent rat ions w er e det er m ined in all t he sam ples of gingival hom ogenat es by t he m et hod of Bradfor d4 ( 1976) using bovine ser um album in ( BSA)
as a st andar d calibrat ion cur ve.
absor bed at 595 nm22.
Th e t ech n iqu e con sist ed of u sin g 1 0 u L of t h e solut ion, and t he t est w as per for m ed on an ELI SA plat e, also know n as a plat e w it h 96 cavit ies or w ells,
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Reader s of t he ELI SA plat e, or m icr o plat e r eader s,
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wavelengt h and m easure t he am ount of light absorbed
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t he sam ples. The dye has a wavelengt h w hen exposed
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A spect r ophot om et er - using a com put er pr ogram - obt ained t he calibrat ion cur ve t o t he dat a pr ovided,
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Analysis of MMP- 8 in gingival t issue
The gingival t issue collect ed by sur gical excision using a disposable no. 15 car bon st eel scalpel blade ( Em bram ac Braz. Com . of Sur gical Mat . im por t and Ex por t Trade I ndust r y Lt d. ; Cam pinas; SP; Brazil) on t he low er left m olar r egion w as st or ed in v ials cont aining 2 m L of Tr is- HCl buffer. This t issue was hom ogenized using an Ult ra 80 ult rasound device ( Ult ra
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w it h 50- m M zinc sulfat e ( Mer ck KgaA; Dar m st adt ; Hessen; Ger m any ) and 0 . 0 5 % poly et hy lene gly col
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USA) w er e added t o t he quar t z cuvet t e. Aft er t hat , t he
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Medical Syst em s; Mulgrave; Vict or ia; Aust ralia) and
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Th e set t i n g s u sed i n t h e f l u o r o m et er ( Var i an Medical Sy st em s; Mulgrave; Vict or ia; Aust ralia) for t h e an aly sis w er e 2 8 0 n m ex cit at ion an d 3 6 0 n m em ission. The enzym e kinet ics w er e evaluat ed based on t he m axim um speed for t he period of 0- 45 m inut es.
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average of t hese values was obt ained for all subsequent calculat ions.
Radiographic m aking and digit al analysis
Aft er eut hanasia of t he anim als, t he j aw s w er e
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hour s. Then t he r ight and left sides of t he pieces w er e divided and t he left side was subm it t ed t o an X- ray
pr ocedur e.
On a t able, t he left hem im andibles ( HMs) w er e p o si t i o n e d w i t h t h e b u cca l su r f a ce s f a ci n g t h e
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Osasco; SP; Brazil) . The st andardizat ion of radiographs was obt ained as follow s:
Using an X- ray m achine - Pam pas - E ( General Elect r ic Com pany; Milwaukee; Wisconsin; USA) , w it h an elect r ic syst em of 65 kVp and 10 m A;
Cen t r al beam of X- r ay s f ocu sin g per pen dicu lar
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sur face of t he opt ical plat e; Focal lengt h of 30 cm ;
Exposur e t im e of 0.8 seconds;
Radiographs were developed using Kodak developer
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m et hod was used.
The radiographs w er e scanned and t he im ages w er e analyzed w it h t he I m agelab pr ogram ( soft ium Com put er Syst em s; São Paulo; SP; Brazil) , using t he t ool for dist ance and angle m easur em ent . Wit h t his feat ure, t he dist ance from t he cem ent oenam el j unct ion t o t he bone cr est was m easur ed at t he m esial sur face
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m easurem ent s were recorded in m illim et ers ( m m ) . The m ouse was posit ioned in t he r egion cor r esponding t o t he cem ent oenam el j unct ion. Aft er t hat , t he left but t on was t r igger ed and dragged dow n t o t he level of t he alveolar crest so t hat t he program w ould aut om at ically m easur e t he dist ance.
Laborat ory processing and hist om et ric analysis
The specim ens were dem ineralized wit h 50% form ic acid and 20% sodium cit rat e solut ions and, aft er t his
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in a sem i- ser ial for m in t he m esiodist al dir ect ion. They w er e 4- m m t hick and w er e st ained w it h hem at oxylin and eosin ( H&E) .
I n or der t o analyze t he int er radicular bone level, a m agn it u de of u p t o 1 2 X w as u sed. Th e ar ea of bone loss ( BL) in t he fur cat ion r egion expr essed in m m2 was hist om et r ically det er m ined using an im age
analy sis sy st em ( I m agelab 2000; Soft war e Diracon Bio I n f or m at ica Lt d . ; Var g em Gr an d e d o Su l, SP,
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fur cat ion in w hich t he r egion was evident , as w ell as
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for hist om et r ic analy sis10. The BL w as assessed by
and t he sur face of t he fur cat ion ceiling cem ent . The select ion of hist ologic sect ions was per for m ed by a t r ain ed inv est igat or w h o w as blin ded t o t h e t r e a t m e n t p e r f o r m e d , w h o a l so co n d u ct e d t h e hist om et r ic analy sis. The BL of each specim en was evaluat ed t hr ee t im es by t he sam e exam iner and on different days9. The t hree m easurem ent s obt ained were VWDWLVWLFDOO\DQDO\]HGIRUWKHUHSHDWDELOLW\FRHI¿FLHQW
obt aining a r eliabilit y of 95%28. The m ean values w er e
st at ist ically checked and com par ed.
St at ist ical analysis
Wit h a sam ple size of 10 ( P< 0.05) t he pow er of t he st udy was 90% . St at ist ical analysis of biochem ical, r ad i o g r ap h i c an d o f t h e h i st o m o r p h o m et r i c d at a o b t a i n e d w a s p e r f o r m e d w i t h t h e Bi o Est a t 3 . 0 soft ware ( Window s 1995 Bioest at Sonopress. Brazilian I ndust r y; Manaus; AM; Brazil) . The hypot hesis of no
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t he differ ent gr oups and per iods in t he t eet h w it h induced per iodont it is was t est ed. Aft er exam inat ion of t he nor m al values of t he Shapir o- Wilk t est , t he int ra
and int er- gr oup analyses w er e per for m ed by analysis of var iance ( ANOVA) t o t w o cr it er ia ( gr oup and per iod) w it h t he Bonfer r oni com plem ent at ion ( p< 0.01) .
Result s
Analysis of MMP- 8 in gingival t issue
S g r o u p ( 7 0 . 0 9 ± 0 . 9 0 u n ; 5 6 . 0 7 ± 1 . 3 2 u n ;
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of MMP- 8 com par ed t o t he NT gr oup ( 150.04± 0.54 un; 129.54± 0.69 un; 116.76± 1.01 un) and SRP group ( 130.03± 1.33 un; 117.37± 0.40 un; 108.33± 1.23 un) in all exper im ent al per iods ( p< 0.01) . The SRP gr oup
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t o t he NT gr oup in all exper im ent al per iods ( p< 0.01) .
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expr ession of MMP- 8 at 30 days w hen com par ed t o expr essions at 7 days ( p < 0.01) ( Figur e 1) .
Radiographic analysis
I n t he radiographic analysis bet ween t he groups, t he S gr oup ( 0.86± 0.34 m m ; 0.66± 1.01 m m ; 0.57± 0.23
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to each group and period
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Figure 2- Means and standard deviations (M±SD) of the distances between the cementum-enamel union and alveolar bone crest (mm)
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t o t he NT gr oup ( 2. 99± 0. 32 m m ; 2. 45± 0. 58 m m ; 1.97± 1.11 m m ) and t he SRP gr oup ( 2.59± 0.09 m m ; 1.86± 0.33 m m ; 1.49± 1.02 m m ) in all exper im ent al
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low er BL com par ed t o t he NT gr oup in all exper im ent al per iods ( p< 0.01) . The anim als of all gr oups show ed a
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( p< 0.01) ( Figur e 2) .
Hist om et r ic analysis
I n hist om et ric analysis bet ween groups, t he S group ( 0.71± 0.23 m m2; 0.64± 0.05 m m2; 0.61± 1.02 m m2) KDG D VLJQL¿FDQWO\ ORZHU ERQH ORVV %/ FRPSDUHG
t o t he NT gr oup ( 1.67± 0.13 m m2; 1.47± 1.05 m m2;
1.41± 1.17 m m2) and t he SRP group ( 1.09± 0.10 m m2;
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group, 15 days; F- S group, 15 days; G – NT group, 30 days; H - SRP group, 30 days; I- S group, 30 days
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1.00± 0.08 m m2; 0.89± 0.45 m m2) in all exper im ent al SHULRGVS7KH653JURXSKDGDVLJQL¿FDQWO\
low er BL com par ed t o t he NT gr oup in all exper im ent al per iods ( p< 0.01) ( Figur e 3 and Figur e 4) .
Discussion
The m echanical r em oval of dent al plaque by SRP is
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in som e dent al sit es2. Thus, t he aim of t his st udy was
t o evaluat e t he local effect s of st at ins as an adj uvant t reat m ent t o SRP in periodont al disease induced in rat s. The r esult s of t his st udy show ed a slight asym m et r y, pr obably r elat ed t o var iat ions bet w een t he anim als and t he pr ocessing used t o obt ain t he biochem ical, r adiological an d h ist om et r ic dat a. How ev er, w h en per for m ing st at ist ical t est s it was obser ved t hat it had been a nor m al dist r ibut ion of dat a ( param et r ic) .
Th e ch oice of r at s as an ex p er im en t al an im al m odel was based on ot her st udies14. Accor ding t o t he
aut hor, t he rat is favorable as an exper im ent al m odel for t he developm ent and st udy of per iodont al disease due t o t he sim ilar it y of t heir per iodont ium t o t hat of hum ans, w her e t he only differ ence is t he pr esence of kerat inizat ion of t he sulcular epit helium . The m odel of per iodont al disease induct ion used in t his st udy was t he sam e pr oposed in a for m er st udy car r ied out in 197513, w hich used t he placem ent of a cot t on t hr ead
ar ound rat m olar s. The aut hor point ed out t hat t he bandage favors bact erial accum ulat ion, t hus developing per iodont al disease. I n t he pr esent st udy, t his m odel
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per iodont al disease because of t he ligat ur e induced
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Per iodont al disease is charact er ized by clinical signs of
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loss of adhesion of gingival t issue t o t he t oot h. Spon t an eou s h ealin g af t er ligat u r e r em ov al by lack of m echanical t r eat m ent ( SRP) in PD not iceably pr om ot ed in t en se alv eolar bon e r esor pt ion in t h e fur cat ion ar ea r esult ing fr om t he m aint enance of t he pr im ar y et iologic agent s of per iodont it is, as show n by t he hist om et ric analysis at all t im e point s. Periodont it is is charact er ized by epit helial m igrat ion and by t he br eakdow n of connect ive t issue and alveolar bone30.
Thus, t he lack of m echanical t r eat m ent cont r ibut es t o t he pr ogr ession and evolut ion of PD in t he pr esent st udy. The dat a pr esent ed her e clear ly dem onst rat e PD r em ission aft er SRP t r eat m ent , t hus cor r oborat ing
t he consensus in t he lit erat ur e t hat SRP t r eat m ent is effect ive in per iodont it is r em ission9 com par ed w it h t he
fr ee pr ogr ession of per iodont it is, w her ein t he r em oval of t h e aggr essor is n ot per f or m ed by m ech an ical t r eat m en t . Alt h ou gh t h e SRPs ex h ibit sat isf act or y r esult s in t he pr esent st udy, excessive penet rat ion of inst r um ent s in t he per iodont al pocket bot t om can lead t o an inser t ion loss in t eet h w it h lit t le pr obing dept h17. +RZHYHU WKH EHQH¿WV RI SHQHWUDWLRQ RI SHULRGRQWDO
inst r um ent s in t he bot t om of t he bag, dir ect ed for t he r em oval of bact er ial deposit s pr esent on t he r oot
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by t he t raum a pr oduced2.
The use of adj uvant s for t he per iodont al t r eat m ent was aim ed t o decr ease or elim inat e m icr oor ganism s t h a t co n t r i b u t e t o t h e o n se t o r p r o g r e ssi o n o f periodont it is. Pharm acologic agent s for syst em ic29 and
t opical13 use ar e applied for t his pur pose. St udies19,20
h av e addr essed t h e u se of su bst an ces t h at af f ect t he act ivit y of ost eoclast s because t hese cells cause alveolar bone breakdown in periodont it is20. Accordingly,
st at in s, w h ich ar e dr u gs t h at in h ibit t h e act ion of ost eoclast s, are considered pot ent agent s in t he cont rol of bone resorpt ion21,23. I n t he present st udy, periodont al
pocket s w er e ir r igat ed w it h 1 m L Sim vast at in gel aft er SRP. Syst em ic effect s of t he accident al ingest ion of Sim vast at in by anim als dur ing local t r eat m ent s could
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const ipat ion, nausea, and t he em er gence of ot her unpleasant r eact ions5. But t hese changes w er e not
obser ved in t he anim als of t his st udy because dur ing t he t r eat m ent s t he or ophar yngeal r egion of each pet was pr ot ect ed w it h a st er ile gauze t her eby pr event ing t he int ake of any gels and pr event ing t he syst em ic act ion of sim vast at in.
Mat rix m et alloprot einases ( MMPs) play an im port ant r o l e i n t i ssu e r e m o d e l i n g d u r i n g d e v e l o p m e n t , h om eost asis an d w ou n d h ealin g2 6. An im b alan ce
bet w een MMPs and t heir act ivat ed der ivat ives of t he host endogenous inhibit or s, t he inhibit or s of m at r ix m et allopr ot einase ( TI MP) , leads t o t he pat hological br eakdow n of t he ext racellular m at r ix in per iodont al d isease2 6. Am on g ot h er act iv it ies, MMPs d eg r ad e FROODJHQ¿EHUVLQVHUWHGLQWRWKHWRRWKURRWDOORZLQJ
apical m igrat ion and lat eral ext ension of t he pocket epit helium . The clinical sequelae of t he pat hologic in cr ease in collag en d est r u ct ion ar e t h e in ser t ion loss, bone loss and for m at ion of per iodont al pocket s1.
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b r on ch it is, ast h m a an d ar t h r it is. Recen t ly it h as been show n t o exer t an unexpect ed defensive ant i-i n f l am m at or y act i-i v i-i t y, w h i-i ch p r ov i-i d es p r ot ect i-i on ag ain st ex p er im en t al sk in can cer scat t er in g an d
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im m une response12. Along w it h MMP- 9 and neut
rophil-der ived 13 rophil-der ived fr om bone or skin cells, MMP-8 st ands out am ong MMPs pr edom inant ly pr esent in
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in per i- im plant s. The level and degr ee of act ivat ion of t hese enzym es seem s t o incr ease w it h t he incr eased act ivit y and sever it y of per iodont al disease, and t hen decr eases aft er t he t r eat m ent w it h scaling and r oot planing ( SRP)12.
A r ecen t st u d y sh o w ed t h at MMP- 8 l ev el s i n pat ient s t hat were bot h sm okers and non- sm okers wit h
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periodont al t herapy SRP1. This was dem onst rat ed in t he
pr esent st udy, consider ing t hat in MMP- 8 expr ession in t r a- gr ou ps, t h e an im als of all gr ou ps sh ow ed a
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30 days aft er local t r eat m ent s.
I t is also p ossib le t o ob ser v e t h at an im als in t h e S gr ou p h ad ex pr ession s of MMP- 8 t h at w er e
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in all exper im ent al per iods, pr obably due t o t he ant
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in t he current year16 st rengt hens t his hypot hesis, since
it dem onst rat ed t hat t opical applicat ion of Sim vast at in w as ab le t o r ed u ce t h e in f lam m at or y p r ocess in ex p er im en t al p er iod on t it is in r at s. I n 2 0 0 3 , Lu an and collaborat or s18 found t hat st at ins decr ease t he SURGXFWLRQRIPDQ\SURLQÀDPPDWRU\F\WRNLQHVDQG
it has been descr ibed t hat t hey favor t he decr eased secr et ion of ot her m at r ix m et allopr ot einases in vit r o.
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p r o v i d i n g p r o t e ct i o n a g a i n st t h e d e st r u ct i o n o f per iodont al t issue.
S t a t i n d r u g s a r e i n h i b i t o r s o f t h e e n z y m e 3- hydr oxy- 3- m et hyl- glut ar yl- coenzym e A ( HMG- CoA) r edu ct ase, leadin g t o t h e pr odu ct ion m an agem en t o f ch o l est er o l2 4 , 2 5 , 2 7. Am o n g t h e v a r i o u s st a t i n s,
Sim vast at in, w hich has been w idely used in clinical p r act ice t o con t r ol ch olest er ol, h as p r ov en t o b e pharm acologically safe. I n addit ion t o it s hypolipidem ic funct ion, t his st at in is not able for ot her side effect s,
LQFOXGLQJDQWLLQÀDPPDWRU\27, im m unom odulat ory and
ant iox idant pr oper t ies, as w ell as t he pr om ot ion of angiogenesis and incr eased ost eoblast differ ent iat ion, inducing bone for m at ion6. These pr oper t ies pr ov ide
gr eat pot ent ial for st at ins t o m odify t he cour se of
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per iodont it is m ay be included.
St at ins hav e differ ent effect s on bone, such as increasing form at ion. Hence, t he choice of Sim vast at in in t he pr esent st udy was consider ed since t he effect s show n ar e m or e int ense3, as w ould also be t he effect
w i t h At o r v a st a t i n a n d Ce r i v a st a t i n . Co n v e r se l y, Lov ast at in an d Pr av ast at in ex h ibit lit t le ef f ect . I n addit ion, Sim vast at in st ands out w hen act ing at m aj or
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as m ent ioned befor e.
I n t h e r ad i o g r ap h i c an d h i st o m et r i c an al y ses
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BL com par ed t o t he NT and SRP gr oups at 7, 15 and 3 0 day s, r espect iv ely. Published st udies hav e also
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loss in exper im ent al per iodont it is in rat s16,19. One of
t he fact or s t hat could ex plain t hese r esult s is t hat st at ins inhibit t he t ransfor m at ion of pr e- ost eoclast s in ost eoclast s t hrough bone m arrow cells and ost eoblast s v ia indir ect act ion. Ost eoblast s r ecr uit and act ivat e ost eoclast s by RANKL int eract ion on t he sur face, w it h t he RANK recept or in t he hem at opoiet ic precursor cells of ost eoclast s. This ost eoclast act ivat ion is cont r olled by ost eoblast s by m eans of t he OPG secr et ion of a soluble r ecept or t hat com pet es w it h RANK for RANKL t o inhibit t he r ecr uit m ent of ost eoclast s, m aint aining a balance bet w een t hem25.
The act ion of st at ins derives also from t he inhibit ion of ost eoblast apopt osis by t he act ion of t ransfor m ing
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in bon e f or m at ion , w it h Sm ad pr ot ein s ( “ m ot h er s against decapent aplegic” ) belonging t o t his signaling pat hway29,30. Ther e is evidence of ost eoblast apopt osis
inhibit ion r egulat ed by Pit avast at in, Mevast at in and Sim vast at in, due t o t he higher expr ession of Sm ad 3 ( “ m ot hers against 3 hom olog decapent aplegic” ) , which funct ions as a signal t ransducer and a m odulat or of t ranscr ipt ion21, 23, 30. The act iv e Sm ad 3 is cr ucial t o
m aint ain bone for m at ion, w hile it s suppr ession leads t o ost eoblast apopt osis23,30.
be unw ise t o ex t rapolat e t he r esult s t o t he hum an species; t hus, fur t her st udies of t he lit erat ur e ar e needed. Ther efor e, w it hin t he lim it s of t his st udy, it is possible t o conclude t hat a locally applied st at in was effect ive as an adj uvant t r eat m ent t o t he SRP in induced per iodont al disease in rat s.
Acknow ledgem ent s
The aut hor s w ould like t o t hank t he Dent al School of t he Federal Univer sit y of Alfenas – UNI FAL/ MG.
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