'XCNWCVKQPQH4CFKQ2TQVGEVKXG'ƑGEVQH/GNCVQPKPQP9JQNG
$QF[+TTCFKCVKQP+PFWEGF.KXGT6KUUWG&COCIG
$OLUH]D6KLUD]L3K'1(KVDQ0LKDQGRRVW06F2*KD]DOH*KREDGL3K'30HKUDQ0RKVHQL3K'4 0DKPRXG*KD]LNKDQVDUL3K'5
'HSDUWPHQWRI0HGLFDO3K\VLFVDQG%LRPHGLFDO(QJLQHHULQJ)DFXOW\RI0HGLFLQH7HKUDQ8QLYHUVLW\RI0HGLFDO 6FLHQFHV7HKUDQ,UDQ
'HSDUWPHQWRI0HGLFDO5DGLDWLRQ(QJLQHHULQJ6FLHQFHDQG5HVHDUFK%UDQFK,VODPLF$]DG8QLYHUVLW\7HKUDQ,UDQ 'HSDUWPHQWRI5DGLDWLRQ2QFRORJ\8QLYHUVLW\0HGLFDO&HQWHU*URQLQJHQ8QLYHUVLW\RI*URQLQJHQ*URQLQJHQ7KH
Netherlands
'HSDUWPHQWRI5DGLRORJ\DQG0HGLFDO3K\VLFV)DFXOW\RI3DUDPHGLFLQH.DVKDQ8QLYHUVLW\RI0HGLFDO6FLHQFHV .DVKDQ,UDQ
'HSDUWPHQWRI3KDUPDFRORJ\)DFXOW\RI0HGLFLQH7HKUDQ8QLYHUVLW\RI0HGLFDO6FLHQFHV7HKUDQ,UDQ
* Corresponding Address: P.O.Box: 14515-775, Department of Medical Radiation Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran
Email: [email protected]
5HFHLYHG2FW$FFHSWHG-XO
Abstract
Objective: ,RQL]LQJUDGLDWLRQLQWHUDFWVZLWKELRORJLFDOV\VWHPVWRLQGXFHH[FHVVLYHÀX[HV of free radicals that attack various cellular components. Melatonin has been shown to be a direct free radical scavenger and indirect antioxidant via its stimulatory actions on the antioxidant system.The aim of this study was to evaluate the antioxidant role of melatonin against radiation-induced oxidative injury to the rat liver after whole body irradiation.
Materials and Methods: In this experimental study,thirty-two rats were divided into four
JURXSV*URXSZDVWKHFRQWUROJURXSJURXSRQO\UHFHLYHGPHODWRQLQPJNJRQWKH¿UVW
day and 30 mg/kg on the following days), group 3 only received whole body gamma irradiation of 10 Gy, and group 4 received 30 mg/kg melatonin 30 minutes prior to radiation plus whole body irradiation of 10 Gy plus 30 mg/kg melatonin daily through intraperitoneal (IP) injection
IRUWKUHHGD\VDIWHULUUDGLDWLRQ7KUHHGD\VDIWHULUUDGLDWLRQDOOUDWVZHUHVDFUL¿FHGDQGWKHLU
livers were excised to measure the biochemical parameters malondialdehyde (MDA) and glu-tathione (GSH). Each data point represents mean ± standard error on the mean (SEM) of at least eight animals per group. A one-way analysis of variance (ANOVA) was performed to compare different groups, followed by Tukey’s multiple comparison tests (p<0.05).
Results: The results demonstrated that whole body irradiation induced liver tissue damage by increasing MDA levels and decreasing GSH levels. Hepatic MDA levels in irradiated rats that
ZHUHWUHDWHGZLWKPHODWRQLQPJNJZHUHVLJQL¿FDQWO\GHFUHDVHGZKLOH*6+OHYHOVZHUH VLJQL¿FDQWO\LQFUHDVHGZKHQFRPSDUHGWRHLWKHURIWKHFRQWUROJURXSVRUWKHPHODWRQLQRQO\JURXS
Conclusion: The data suggest that administration of melatonin before and after irradia-tion may reduce liver damage caused by gamma irradiairradia-tion.
Keywords: Radiation, Lipid peroxidation, MDA, GSH
Cell Journal(Yakhteh), Vol 14, No 4, Winter 2013, Pages: 294- 297
Citation: 6KLUD]L$50LKDQGRRVW(*KREDGL*K0RKVHQL0*KD]LNKDQVDUL0(YDOXDWLRQRIUDGLRSURWHFWLYHHIIHFW of melatonin on whole body irradiation induced liver tissue damage. Cell J. 2013; 14(4): 294-297.
Introduction
,RQL]LQJUDGLDWLRQLQWHUDFWVZLWKELRORJLFDOV\V
-WHPV WR LQGXFH H[FHVVLYH ÀX[HV RI IUHH UDGLFDOV WKDWDWWDFNYDULRXVFHOOXODUFRPSRQHQWVLQFOXGLQJ WKH'1$SURWHLQVDQGPHPEUDQHOLSLGVOHDGLQJ
WRVLJQL¿FDQWFHOOXODUGDPDJH5DGLDWLRQLQ
-GXFHGOLYHUGLVHDVH5,/'LVDGRVHOLPLWLQJFRP
-plication in treatment. Therefore, the treatment
Lipid peroxidation is believed to be an impor-tant cause of destruction and damage to cell mem-branes and has been suggested to be a contributing factor to the development of oxygen
radical-me-GLDWHGWLVVXHGDPDJH5DGLDWLRQLQGXFHGOLSLG
peroxidation is a free radical process (7). Since these radicals initiate lipid peroxidation, it is ex-pected that patients who undergo whole body ra-diation will have high levels of lipid peroxidation.
0DORQGLDOGHK\GH0'$DQGOLSLGSHUR[LGHVDUH SURGXFWVRIWKHOLSLGSHUR[LGDWLRQSURFHVV0'$
with high cytotoxicity and inhibitory actions on
SURWHFWLYHHQ]\PHVDFWVDVDWXPRUSURPRWHUDQG DFRFDUFLQRJHQLFDJHQW.RFHWDOVKRZHG WKDWWRWDOERG\LUUDGLDWLRQ7%,RIUDWVUHVXOWHGLQ D VLJQL¿FDQW LQFUHDVH LQ OLYHU WLVVXH 0'$ OHYHOV DQGGHFUHDVHRIDQWLR[LGDQWHQ]\PHVDFWLYLWLHV
The antioxidant system consists of low-molec-ular-weight antioxidant molecules, such as
glu-WDWKLRQH*6+DQGYDULRXVDQWLR[LGDQWHQ]\PHV
*OXWDWKLRQHLVRQHRIWKHPRVWLPSRUWDQWPRO
-ecules in the cellular defense against chemically reactive toxic compounds that induce oxidative
VWUHVVZKLOHGHSOHWLRQRIWLVVXH*6+LVRQHRIWKH
primary factors that permits lipid peroxidation to
RFFXU'HFUHDVHGFHOOXODU*6+OHYHOVDQGUHGXFHG
FDSDFLW\IRU*6+V\QWKHVLVVHQVLWL]HFHOOVWRUDGLD
-WLRQLQMXU\6HQHUHWDOVKRZHGWKDWZKROH
ERG\LUUDGLDWLRQRIUDWVUHVXOWHGLQDVLJQL¿FDQWGH
-FUHDVHLQWKHOLYHUWLVVXH*6+OHYHOV
0HODWRQLQ 1DFHW\OPHWKR[\WU\SWDPLQH LV DQ HQGRJHQRXVFRPSRXQGV\QWKHVL]HGE\WKHSLQHDO
gland in the human brain (10-12). Studies have
VKRZQWKHGLIIHUHQWIHDWXUHVWKDWPDNHPHODWRQLQD
potentially useful radioprotector, such as the direct scavenging of free radicals; the ability to stimulate
WKHDFWLYLW\RIDQWLR[LGDQWHQ]\PHVDQGWRLQKLELW
WKH DFWLYLW\ RI D SURR[LGDWLYH HQ]\PH GLVWULEX
-tion in all tissues, cells,and cellular compartments
WKURXJKRXWWKHRUJDQLVPTXLFNGLIIXVLRQWKURXJK
all biological membranes; ability to provide radio-protection without receptor interaction; tolerance to high doses of melatonin by living organisms and little toxicity in the species tested; ease of oral
ad-PLQLVWUDWLRQHWF
7KHVHPHFKDQLVPVUHTXLUHWKHSUHVHQFHRIPHOD
-tonin at the time the cells and tissues are irradiated
7KHZLGHVSUHDGGLVWULEXWLRQRIPHODWRQLQ
in subcellular compartments such as cytosol,
nu-cleus, mitochondria, and cellular membrane have allowed it to effectively protect various normal
FHOOVIURPR[LGDWLYHGDPDJHLQGXFHGE\LRQL]LQJ UDGLDWLRQ
9LMD\DOD[PLHWDOUHSRUWHGWKDWPHODWRQLQ
protects or reduces gamma radiation-induced
chro-PRVRPHGDPDJHPLFURQXFOHLDQGSULPDU\'1$
damage in human peripheral blood lymphocytes in their in vitro and in vivo/ in vitro investigations.
0HODWRQLQDOVRLQFUHDVHVLQWUDFHOOXODUJOXWDWKLRQH *6+OHYHOVE\VWLPXODWLQJWKHV\QWKHVLVRIWKH
UDWHOLPLWLQJ HQ]\PH ȖJOXWDP\OF\VWHLQH V\Q
-WKDVHZKLFKLQKLELWVWKHSHURR[LGDWLYHHQ]\PHV QLWULFR[LGHV\QWKDVHDQGOLSR[\JHQDVH7KHUH
LVDOVRVRPHHYLGHQFHWKDWPHODWRQLQVWDELOL]HVPL
-crosomal membranes and thereby probably helps
WKHPUHVLVWR[LGDWLYHGDPDJH0RUHRYHUWKH
radio-protective effect of melatonin against organ damage induced by irradiation has been reported
E\6HQHUHWDODQG(O0LVVLU\HWDO
In this study the antioxidant role of melatonin against oxidative damage caused by gamma irra-diation in liver tissue after whole body rairra-diation was investigated.
Materials and Methods
Chemicals
$OO UHDJHQWV ZHUH RI WKH KLJKHVW TXDOLW\ DYDLO
-DEOH0HODWRQLQZDVREWDLQHGIURPVLJPD&KHPL
-FDO&R6W/RXLV0286$DQGRWKHUFKHPLFDOV
used in this study were obtained from both sigma
6W/RXLV0286$DQG0HUFN*HUPDQ\
Animals
Adult male albino wistar rats weighing
J ZHUH REWDLQHG IURP WKH ([SHULPHQWDO $QLPDO /DERUDWRU\ VHFWLRQ RI WKH 'HSDUWPHQW
RI 3KDUPDFRORJ\ 7HKUDQ 8QLYHUVLW\ RI 0HGL
-cal Sciences, and were housed in stainless steel cages and supplied with wood chips, in a
tem-SHUDWXUHFRQWUROOHGURRPÛ&DQGDKRXU OLJKWGDUNF\FOH7KHDQLPDOVZHUHDOORZHGIUHH
access to tap water and a standard diet for the duration of the study. The experimental proto-col was in accordance with the guidelines for care and use of laboratory animals as adopted
-FLQH 7HKUDQ 8QLYHUVLW\ RI 0HGLFDO 6FLHQFHV
Tehran, Iran.
Experimental design
In this experimental study, thirty-two rats were divided into four groups. Group 1 did not receive melatonin or irradiation (Control group) but
re-FHLYHGȝ/LVRWRQLF1D&OVROXWLRQDVDYHKLFOH LQWUDSHULWRQHDOO\ ,3 JURXS 0HO JURXS RQO\ UHFHLYHGPHODWRQLQPJNJRQWKH¿UVWGD\DQG PJNJPHODWRQLQGDLO\WKURXJKLQWUDSHULWRQHDO LQMHFWLRQIRUWKUHHGD\VDIWHULUUDGLDWLRQJURXS UHFHLYHGȝ/LVRWRQLF1D&OVROXWLRQ,3DQG
was exposed to 10 Gy whole body gamma
irradia-WLRQ*\JURXSDQGJURXSUHFHLYHGPJNJ PHODWRQLQ,3PLQXWHVSULRUWRUDGLDWLRQSOXV ZKROH ERG\ LUUDGLDWLRQ RI *\ SOXV PJNJ PHODWRQLQGDLO\WKURXJK,3LQMHFWLRQIRUWKUHHGD\V DIWHULUUDGLDWLRQ0HO*\JURXS
5DWVLQJURXSVDQGZHUHJLYHQDQ,3LQMHFWLRQ RIIUHVKO\SUHSDUHGPHODWRQLQLQȝ/RI
DEVROXWHHWKDQROVROXWLRQ0HODWRQLQZDV¿UVWGLV
-VROYHGLQDVPDOODPRXQWRIDEVROXWHHWKDQRO ȝ/DQGWKHQGLOXWHGZLWKLVRWRQLF1D&OVROXWLRQWR JLYHD¿QDOHWKDQROFRQFHQWUDWLRQRI
$QLPDOV ZHUH IROORZHG IRU GD\V DIWHU UDGLD
-WLRQGXULQJZKLFKPHODWRQLQPJNJLQMHFWLRQV ZHUHUHSHDWHGIRUJURXSVDQGRQFHGDLO\$W WKHHQGRIWKLVSHULRGDOOUDWVZHUHVDFUL¿FHGDQG
their livers were excised to measure the
biochemi-FDOSDUDPHWHUVLH0'$DQG*6+
Irradiation
$OORIWKHUDWVZHUHDQHVWKHWL]HGZLWKDQ,3LQMHF
-WLRQRINHWDPLQHPJNJDQGFKORUSURPD]LQH PJNJ DQG WKHQ WKH UDWV LQ JURXSV DQG
were exposed to a whole-body gamma radiation dose of 10 Gy. Irradiation was performed using a
FREDOWWHOHWKHUDS\XQLW7KHUDWURQ$WRPLF
energy of Canada limited, Canada) at a dose rate
RI F*\PLQXWH XVLQJ WKH 6LQJOHZDYHOHQJWK DQRPDORXV GLVSHUVLRQ 6$' PHWKRG >6$' FP)LHOGDW6$' FPFPFP@
Tissue preparation and biochemical analysis
Three days after irradiation the rats were
anes-WKHWL]HG DQG WKH DEGRPHQ RSHQHG LPPHGLDWHO\
for access to and examination of the liver. After
opening the abdomen, 1ml of 0.9% cold saline was injected into the portal vein. The liver was excised
DQGEORWGULHGPJRIWKHOHIWORZHUOREHRIWKH OLYHUVZDVKRPRJHQL]HGLQPORIFROGVDOLQH 7KHQPORIWULFKORURDFHWLFDFLG7&$ZDV DGGHGWRWKHKRPRJHQDWHDQGFHQWULIXJHGDW USP IRU PLQXWHV 7KH FOHDU XSSHU VXSHUQDWDQW
ZDVXVHGIRUPHDVXULQJ*6+FRQWHQWDQGWKHVHGL
-PHQWZDVXVHGIRUPHDVXULQJWKH0'$OHYHO
MDAanalysis
7KH0'$OHYHOZDVGHWHUPLQHGDFFRUGLQJWRWKH WKLREDUELWXULFDFLG7%$PHWKRG%ULHÀ\
PORI0VXOIXULFDFLGDQGPORIDVROX
-WLRQRI7%$ZHUHDGGHGWRWKHVHGLPHQW7KHPL[
-WXUHZDVKHDWHGDWÛ&IRUPLQXWHVLQDERLO
-ing water bath. Four cubic centimetres of n-butanol were added to the cooled mixture and the sample
ZDVVKDNHQYLJRURXVO\$IWHUFHQWULIXJDWLRQDW
rpm for ten minutes, the organic layer was removed
DQGLWVDEVRUEDQFHUHDGDWQP7KH0'$FRQ
-centration was calculated from the standard curve.
7HWUDHWKR[\SURSDQH7(3ZDVXVHGDVWKHVWDQGDUG
for setting up the calibration curve.
GSH analysis
*6+OHYHOZDVGHWHUPLQHGDFFRUGLQJWRWKHPHWK
-RGRI.XRDQG+RRN%ULHÀ\FFGLVWLOOHG
ZDWHUFFRI0GLVRGLXPSKRVSKDWH1D2+32)
DQGFFRIGLWKLRELVQLWUREHQ]RLF DFLG'71%ZHUHDGGHGWRFFRIWKHVXSHUQDWDQW
and incubated for ten minutes at room temperature. The absorbance of the resulting yellow color was
UHDGDJDLQVWWKHEODQNDWQPDQGWKH*6+FRQ
-centration was calculated from the standard curve.
3XUH*6+ZDVXVHGDVWKHVWDQGDUGIRUHVWDEOLVKLQJ
the calibration curve.
%LRFKHPLFDO PHDVXUHPHQWV ZHUH FDUULHG RXW
at room temperature using a spectrophotometer
3KDUPDFLD%LRWHFK&DPEULGJH8.
Statistical analysis
Each data point represents the mean ± standard
HUURURIWKHPHDQ6(0RIDWOHDVWHLJKWDQLPDOV
per group. A one-way analysis of variance (ANO-VA) was performed to compare different groups,
Results
MDA levels
$VFDQEHVHHQLQ¿JXUH0'$OHYHOVLQWKHLUUD
-GLDWHGRQO\JURXSSZHUH VLJQL¿FDQWO\KLJKHUFRPSDUHGZLWKHLWKHUWKHFRQWURO JURXSSRUWKHPHODWRQLQ RQO\JURXSS0HODWRQLQ SUHWUHDWPHQW DQG WUHDWPHQW VLJQL¿FDQWO\ UHGXFHG 0'$OHYHOVLQWKHOLYHUVRIUDWVVXEMHFWHGWRZKROH ERG\LUUDGLDWLRQS
b
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
MDA
(nmol/mg protein)
Groups
Control Mel
10 Gy
Mel + 10 Gy
a
Fig 1: The effect of melatonin on MDA levels in rats subject-ed to whole body gamma irradiation. Data represent mean ± standard error ofthe mean (SEM) (n=8 animals per group). a; P<0.05 (compared to control group), and b; P<0.05 (com-pared to the radiated groups).
GSH levels
$VVKRZQLQ¿JXUHWKHOHYHOVRI*6+LQWKH
OLYHUWLVVXHVVLJQL¿FDQWO\GHFUHDVHGLQWKHLUUDGLDW
-HGRQO\JURXSSZKHQFRP
-SDUHGWRHLWKHUWKHFRQWUROJURXS S RU WKH PHODWRQLQ RQO\ JURXS
S0HODWRQLQSUHWUHDWPHQWDQGWUHDW
-PHQW VLJQL¿FDQWO\ UHYHUVHG WKH *6+ OHYHOV RI UDWVH[SRVHGWRZKROHERG\LUUDGLDWLRQ S
b
22
20
18
16
14
12
10
8
6
4
2
GSH (umol/mg protein)
Groups
a
Control
Mel 10 Gy
Mel + 10 Gy
Fig 2: The effect of melatonin on GSH levels in rats sub-jected to whole body gamma irradiation. Data represent mean ± standard error of the mean (SEM) (n=8 animals per group).a; P<0.05 (compared to control group), and b; P<0.05 (compared to the radiated groups).
Discussion
Several studies have demonstrated that melatonin ap-pears to ameliorate irradiation-induced injury in various
RUJDQVLQFOXGLQJWKHVSOHHQOLYHU OXQJFRORQLOHXPOHQVVSLQDOFRUG DQGEUDLQ0HODWRQLQV\QHUJLVWLFDOO\DFWVDVDQ LPPXQRVWLPXODWRUDQGDQWLR[LGDQW 0RUHRYHUGXHWRVPDOOVL]HDQGKLJKOLSRSKLOLFLW\
melatonin crosses biological membranes and reaches
DOOFRPSDUWPHQWVRIWKHFHOO0HODWRQLQKDVEHHQ
shown to be a direct free radical scavenger and indirect antioxidant via its stimulatory actions on antioxidant
en-]\PHDFWLYLW\DQGLQKLELWRU\DFWLRQV RQSURR[LGDWLYHHQ]\PHDFWLYLW\
The results of the present study suggest that whole body irradiation caused tissue damage in the rat liver
DVPDQLIHVWE\LQFUHDVHG0'$OHYHOVDQGGHFUHDVHG
*6+OHYHOV7KHLQFUHDVHLQ0'$OHYHOVLQWKHLUUDGL
-ated group demonstrates the role of oxidative
mecha-QLVPVLQWKHLUUDGLDWLRQLQGXFHGWLVVXHGDPDJH'XHWR
high cytotoxicity and inhibitory actions on protective
$V PHQWLRQHG HDUOLHU *6+ SURYLGHV FRQVLGHU -able protection against oxidative injury through its role in the cellular system of defense against
R[LGDWLYHGDPDJH7KHGHFUHDVHLQWLVVXH*6+OHY
-els after whole body irradiation may be due to its consumption during the oxidative stress induced by irradiation. On the other hand, melatonin ad-ministration before and after radiation, alleviated the radiation toxicity to the liver by reversing the radiation-induced effects. The mechanisms where-by melatonin inhibits lipid peroxidation probably include the direct scavenging of the initiating
radi-FDOVHVSHFLDOO\2+DQG2122Ā$OVRPHOD
-tonin through its indirect antioxidative properties
VWLPXODWHVOHYHOVRI*6+ZKLFKLVDQDQWLR[LGDQW
Several studies have indicated that tissue injuries,
LQGXFHGE\YDULRXVVWLPXOLDUHFRXSOHGZLWK*6+GH
-SOHWLRQDQGKLJKOHYHOVRIOLSLGSHUR[LGDWLRQ
Also,research in the last decade has demonstrated that melatonin, by its free radical scavenging and antioxida-tive properties, ameliorates radiation toxicity in different tissues. Koc and colleagues investigated the antioxidant
UROHRIPHODWRQLQDWDQGPJNJDJDLQVWZKROH
body gamma irradiation induced oxidative damage in
OLYHUWLVVXHZLWKDVLQJOHGRVHRI*\7KHUHVXOWV
demonstrated that in irradiated rats, pretreated with
me-ODWRQLQRUPJNJOLYHUWLVVXH0'$OHYHOVDV DQHQGSURGXFWRIOLSLGSHUR[LGDWLRQZHUHVLJQL¿FDQWO\
lowered, whereas the activities of superoxide dismutase
62'DQGJOXWDWKLRQHSHUR[LGDVH*6+3[WZRRI
WKHPRVWLPSRUWDQWDQWLR[LGDQWHQ]\PHVZHUHVLJQL¿
-cantly increased. The authors concluded that pretreat-ment with melatonin may prevent irradiation induced
OLYHU GDPDJH (O0LVVLU\ HW DO VKRZHG WKDW WUHDWPHQWZLWKPJNJPHODWRQLQIRUGD\VGDLO\
EHIRUHDFXWHLUUDGLDWLRQDQG*\VLJQL¿FDQWO\UH
-GXFHGUDGLDWLRQLQGXFHGHOHYDWLRQVLQ0'$DQGSURWHLQ
FDUERQ\OOHYHOVWKHR[LGDWLYHVWUHVVPDUNHUVLQWKHOLY
-HUDQGPDLQWDLQHGKHSDWLFJOXWDWKLRQH*6+FRQWHQW
glutathione-S-transferase (GST), and catalase (CAT) activities close to the control group values.
6HQHUHWDOHYDOXDWHGWKHOHYHOVRI0'$DQG*6+
in liver, lung, colon and intestinal tissues. The results demonstrate that both 12 hours and 72 hours following
LUUDGLDWLRQWLVVXHOHYHOVRI0'$ZHUHHOHYDWHGZKLOH *6+OHYHOVZHUHUHGXFHGLQOLYHUDQGRWKHURUJDQV2Q WKHRWKHUKDQGPHODWRQLQUHGXFHGWKHOHYHOVRI0'$ DQGLQFUHDVHGWKH*6+OHYHOVVLJQL¿FDQWO\
In a study from our laboratory, we assessed the radio-protective effects of melatonin on biochemi-cal, histopathologibiochemi-cal, and clinical manifestations of
UDGLDWLRQP\HORSDWK\50LQWKHUDWFHUYLFDOVSLQDO FRUG$GPLQLVWUDWLRQRIPHODWRQLQPDUNHGO\UHGXFHG 0'$ DQG LQFUHDVHG *6+ OHYHOV ZKHQ FRPSDUHG ZLWKWKHFRQWUROJURXS6LPLODUO\QHZGDWDIURP
another study have shown that radiation exposure
de-FUHDVHGOHYHOVRI*6+DQGLQFUHDVHGOHYHOVRI0'$
in the lens, but these values were within normal
lim-LWVZKHQPHODWRQLQZDVDGPLQLVWHUHG
In our current study, results for the irradiation plus melatonin groups were similar to the results of previous studies in which treatment with melatonin increased
*6+OHYHOVEXWGHFUHDVHGOHYHOVRI0'$7KXVRXU
results are in agreement with other studies and support
¿QGLQJVSUHYLRXVO\SXEOLVKHGLQWKHOLWHUDWXUH
20, 22).In our most recent study prior to this one, we investigated the possible radio-protective effects of
me-ODWRQLQPJNJDJDLQVWZKROHERG\LUUDGLDWLRQ DQG*\LQGXFHGR[LGDWLYHGDPDJHWRUDWVSHULSKHUDO
blood at different time points after exposure. Treatment
ZLWKPHODWRQLQPJNJDPHOLRUDWHGWKHKDUPIXOHI
-fects irradiation by increasing the lymphocyte count
/&DQGDQWLR[LGDQWHQ]\PHDFWLYLW\DQGGHFUHDVLQJ
QLWULFR[LGH12OHYHOVDWDOOWLPHSRLQWV:HFRQ
-FOXGHGWKDWPJNJPHODWRQLQLVOLNHO\WREHDQDG
-HTXDWHFRQFHQWUDWLRQIRUVLJQL¿FDQWSURWHFWLRQDJDLQVW WKHORZHUGRVHRI*\EXWGRHVQRWSURYLGHVLJQL¿FDQW SURWHFWLRQDJDLQVWWKHKLJKHUGRVHRI*\,WVHHPV
therefore, that the radio-protective effects of melatonin are dose-dependent (27).
'HVSLWH WKH ODFN RI FOLQLFDO DQG H[SHULPHQWDO VWXGLHVRWKHULQYHVWLJDWRUV¿QGLQJVWDNHQWRJHWKHU ZLWKSUHVHQWUHVXOWVDQGRXUSUHYLRXVVWXGLHV
VXJJHVWWKDWDGPLQLVWUDWLRQRIPHOD
-tonin may enable the use of higher doses of
irradi-DWLRQGXULQJUDGLRWKHUDS\DQGPD\EHEHQH¿FLDOLQ
alleviating the complications of cancer treatment.
Conclusion
%DVHGRQRXUUHVXOWVLRQL]LQJUDGLDWLRQFDXVHV
oxidative damage while melatonin, due to its anti-oxidative properties, ameliorates radiation induced injury to the rat liver. In conclusion, our results
VKRZWKDWDFRQFHQWUDWLRQRIPJNJPHODWRQLQ LVOLNHO\WRSURYLGHVLJQL¿FDQWSURWHFWLRQDJDLQVW
*\JDPPDLUUDGLDWLRQRIUDWOLYHU7KHVH¿QG
-ings hold the promise that in future higher concen-trations or long-term administration of melatonin may provide more protection against higher doses of irradiation induced oxidative stress in various organs. Further experiments and clinical trials
Acknowledgments
This study was supported by grant numbers 2709 and IURP WKH YLFH FKDQFHOORU RI UHVHDUFK DW 7HKUDQ 8QLYHUVLW\RI0HGLFDO6FLHQFHV:HJUDWHIXOO\DFNQRZO -edge the pharmacology laboratory and the Radiotherapy 'HSDUWPHQW RI &DQFHU ,QVWLWXWH VWDIIV HVSHFLDOO\ 0V 0DKERG(VIDKDQLIRUWKHJUHDWKHOSDQGDGYLFHIRUWKLV VWXG\7KHUHLVQRFRQÀLFWRILQWHUHVWLQWKLVVWXG\
References
1. 0DQVRXU+++DIH]+))DKP\10+DQD¿13URWHFWLYH effect of N-acetylcysteine against radiation induced DNA damage and hepatic toxicity in rats. Biochem Pharmacol. 2008; 75(3): 773-780.
2. Shirazi A, Mehdipour Z, Jalilian A, Mihandoost E. Radio-protective effects of some bis-thiosemicarbazone com-pounds. J Biomed Phys Eng. 2012; 2(1): 31-36. 3. Lawrence TS, Robertson JM, Anscher MS, Jirtle RL,
En-sminger WD, Fajardo LF. Hepatic toxicity resulting from cancer treatment. Int J Radiat Oncol Biol Phys. 1995; 31(5): 1237-1248.
4. Dawson LA, Normolle D, Balter JM, McGinn CJ, Law-rence TS, Ten Haken RK. Analysis of radiation-induced liver disease using the Lyman NTCP model. Int J Radiat Oncol Biol Phys. 2002; 53(4): 810-821.
5. 7D\VL6.RF0%\NRNXUR÷OX0($OWLQND\QDN.6DKLQ YN. Melatonin reduces lipid peroxidation and nitric oxide during irradiation- induced oxidative injury in the rat liver. J Pineal Res. 2003; 34(3): 173-177.
6. Koc M, Taysi S, Buyukokuroglu ME, Bakan N. Melatonin protects rat liver against irradiation-induced oxidative in-jury. J Radiat Res. 2003; 44(3): 211-215.
7. 2KVKLPD + %DUWVFK + &KURQLF LQIHFWLRQV DQG LQÀDP-matory processes as cancer risk factors: possible role of nitric oxide in carcinogenesis. Mutat Res. 1994; 305(2): 253-264.
8. Sharma S, Haldar C. Melatonin prevents X-ray irradiation induced oxidative damagein peripheral blood and spleen of the seasonally breeding rodent, Funambulus pennanti during reproductively active phase. Int J Radiat Biol. 2006; 82(6): 411-419.
9. 6HQHU*-DKRYLF17RVXQ2$WDVR\%0<H÷HQ%&0H-latonin ameliorates ionizing radiation-induced oxidative organ damage in rats. Life Sci. 2003; 74(5): 563-572. 10. Tan DX, Chen LD, Poeggeler B, Manchester LC,
Re-iter RJ. Melatonin: a potent, endogenous hydroxyl radical scavenger. Endocr J. 1993; 1(4): 57-60.
11. Sharma S, Haldar C, Chaube SK. Effect of exogenous melatonin on X-ray induced cellular toxicity in lymphatic tissue of Indian tropical male squirrel, Funambulus pen-nanti. Int J Radiat Biol. 2008; 84(5): 363-374.
12. Shirazi A, Ghobadi G, Ghazi-Khansari M. A radiobiological review on melatonin: a novel radioprotector. J Radiat Res. 2007; 48(4): 263-272.
13. Karbownik M, Reiter RJ. Antioxidative effects of melatonin in protection against cellular damage caused by ionizing radiation. Proc Soc Exp Biol Med. 2000; 225(1): 9-22. 14. Vijayalaxmi, Reiter RJ, Tan DX, Herman TS, Thomas CR
Jr. Melatonin as a radioprotective agent: a review. Int J Radiat Oncol Biol Phys. 2004; 59(3): 639-653.
15. Shirazi A, Haddadi GR, Ghazi-khansari M, Abolhassani F, Mahdavi S, Eshraghyan M. Evaluation of melatonin for prevention of radiation myelopathy in irradiated cervical
spinal cord. Cell J. 2009; 11(1): 43-48.
16. Vijayalaxmi, Reiter RJ, Sewerynek E, Poeggeler B, Leal BZ, Meltz ML. Marked reduction of radiation-induced mi-cronuclei in human blood lymphocytes pretreated with melatonin. Radiat Res 1995; 143(1): 102-106.
17. Vijayalaxmi, Reiter RJ, Meltz ML. Melatonin protects hu-man blood lymphocytes from radiation-induced chromo-some damage. Mutat Res. 1995; 346(1): 23-31. 18. Vijayalaxmi, Reiter RJ, Herman TS, Meltz ML. Melatonin
re-duces gamma radiation-induced primary DNA damage in hu-man blood lymphocytes. Mutat Res. 1998; 397(2): 203-208. 19.
.DUERZQLN0*DUFLD--/HZLĔVNL$5HLWHU5-&DUFLQ-ogen-induced, free radical-mediated reduction in micro-VRPDO PHPEUDQH ÀXLGLW\ UHYHUVDO E\ LQGROHSURSLRQLF acid. J Bioenerg Biomembr. 2001; 33(1): 73-78.
20. El-Missiry MA, Fayed TA, El-Sawy MR, El-Sayed AA. Ameliorative effect of melatonin against gamma-irradia-tion-induced oxidative stress and tissue injury. Ecotoxicol Environ Saf. 2007; 66(2): 278-286.
21. Esterbauer H, Cheeseman KH. [42] Determination of alde-hydic lipid peroxidation products: malonaldehyde and 4-hy-droxynonenal. Methods Enzymol. 1990; 186: 407-421. 22. Sharma S, Haldar C, Chaube SK, Laxmi T, Singh
SS.Long-term melatonin administration attenuates low-LET gamma-radiation-induced lymphatic tissue injury during the repro-ductively active and inactive phases of Indian palm squirrels (Funambulus pennanti). Br J Radiol. 2010; 83(986): 137-151. 23. Shirazi A, Haddadi GH, Asadi-Amoli F, Sakhaee S, Ghazi-Khansari M, Avand A. Radioprotective effect of melatonin in reducing oxidative stress in rat lenses. Cell J. 2011; 13(2): 79-82.
24. .DUVOLRJOX,(UWHNLQ097D\VL6.RoHU,6H]HQ2*HSGL-remen A, et al. Radioprotective effects of melatonin on radi-ation-induced cataract. J Radiat Res. 2005; 46(2): 277-282. 25. Aghazadeh S, Azarnia M, Shirazi A, Mahdavi SR, Minaee
Zangii B. Melatonin as a protective agent in spinal cord damage after gamma irradiation. Reports of Practical On-cology and Radiotherapy. 2007; 12(2): 95-99.
26. Erol FS, Topsakal C, Ozveren MF, Kaplan M, Ilhan N, Ozercan IH, et al. Protective effects of melatonin and vi-tamin E in brain damage due to gamma radiation. Neuro-surg Rev. 2004; 27(1): 65-69.
27. Shirazi A, Mihandoost E, Mohseni M, Ghazi-Khansari M, Rabie Mahdavi S. Radio-protective effects of melatonin against irradiation-induced oxidative damage in rat pe-ripheral blood. Phys Med. 2013; 29(1): 65-74.
28. Reiter R, Tan DX, Osuna C, Gitto E. Actions of melatonin in the reduction of oxidative stress. J Biomed Sci. 2000; 7(6): 444-458.
29. Rodriguez C, Mayo JC, Sainz RM, Antolín I, Herrera F, Martín V, et al. Regulation of antioxidant enzymes: a sig-QL¿FDQWUROHIRUPHODWRQLQ-3LQHDO5HV 30. Orbak Z, Ertekin V, Yildirim M, Ertekin V, Seven B, Karslio-glu I. Effect of melatonin on bone mineral density of irradi-ated rats. Cell J. 2011; 12(4): 459-462.
31. Mihandoust E, Shirazi A. Application of radioprotective agents in cancer treatment. Iran J Nucl Med. 2010; 18 Suppl 1: 107. 32. Stone HB, Coleman CN, Anscher MS, McBride WH. Ef-fects of radiation on normal tissue: consequences and mechanisms. Lancet Oncol. 2003; 4(9): 529-536. 33. Akpolat M, Kanter M, Uzal MC. Protective effects of
cur-cumin against gamma radiation-induced ileal mucosal damage. Arch Toxicol. 2009; 83(6): 609-617.
