M E D iC A L
0
A L
O so rio M ig u e l P a rra , R u b e n s A u g u sto P e n te a d o d e S o u sa
e S ilva , Jo se R o b e rto M a ch a d o C u n h a d a S ilva , F ra n cisco Ja vie r H e rn a n d e z-B la sq u e z, L u ig i P e d u to ,
W illia m A b ra o S a a d , W illia m A b ra o S a a d Ju n io r
E n h a n c e m e n t o f liv e r siz e
by
stim u la tio n o f in ta c t ra t liv e r
w ith e x o g e n o u s h e p a to tro p h ic fa c to rs
D e p a r t m e n t o f H i s t o l o g y a n d E m b r i o l o g y o f t h e I n s t i t u t o d e C i e n c i a s B i o m e d i c a s o f U n i v e r s i d a d e d e S l i o P a u l o a n d I I S u r g i c a l D i v i s i o n , M e d i c a l S c h o o l o f t h e P o n t i / i c i a U n i v e r s i d a d e C a t 6 l i c a , S o r o c a b a , B r a z i l
In m a m m a ls, live r size is re la te d to a n im a l b o d y w e ig h t a t th e 2 .5 to 3 % p ro p o rtio n , a ra tio m e d ia te d b yth e a fflu x o f h e p a to tro p h ic fa cto rs. F o rm u la s ca p a b le o f m o d ifyin g th is ra tio h a ve b e e n d e ve lo p e d in p re vio u s stu d ie s o n th e ra t, w ith e n h a n ce m e n t o f live r size b ro u g h t a b o u t b y in tra p e rito n e a l (p o rta l) in fu sio n o f e xo g e n o u s fa cto rs su ch a s g lu co se , a m in o a cid s, in su lin , g lu ca g o n , vita m in s,
e le ctro lyte s, a n d triio d o th yro n in e . H o w e ve r, th e e ffica cy o f th e se fo rm u la tio n s w a s a cco m p a n ie d b y in cre a se d a n im a l m o rta lity (P A R R A e t a 1 .1 9 .2 0 ). T h e p re se n t stu d y, w h ich w a s ca rrie d o u t w ith sm a ll m e th o d o lo g ica l m o d ifica tio n s o n a la rg e r n u m b e r o f ra ts u sin g d a ily in tra p e rito n e a l in je ctio n s o f a so lu tio n o f e xo g e n o u s h e p a to tro p h ic fa cto rs (4 0 m l/kg ) fo r se ve n d a ys, co n firm s th e p re vio u s fin d in g s,
w ith a1 1 4 .1 6 : t 7 .9 0 % e n h a n ce m e n t o f live r size b e yo n d th e e xp e cte d va lu e fo rth e b o d y w e ig h t o f th e a n im a l. H o w e ve r, th e p ro b le m
o f a n im a l m o rta lity w a s n o t fu lly re so lve d .
U N IT E R M S : G lu ca g o n . In su lin . L ive r re g e n e ra tio n . T h yro id h o rm o n e .
T
h ea c c o r d in gliv e r h a sto th e tr o p h icth e a b ility" in f lu e n c e "to r e g u la teit r e c e iv e s ,its o w n s iz ei.e ., a c c o r d in g to th e a f f lu x o f th e s e t o f s u b s ta n c e s a n d h o r m o n e s g e n e r ic a lly c a lle d h e p a to tr o p h ic f a c to r s , m a n y o f th e m o f s p la n c h n ic o r ig in , s u c h a s in s u lin , g lu c a g o n , a m in o a c id s , v ita m in s , a n d c e r ta in ly m a n y m o r e o f s till u n k n o w n o r ig in . T h u s , th e r e is a s p e c if ic liv e r s iz e f o r e a c h a n im a l c o r r e s p o n d in g to 2 .5 to 3 % o f b o d y w e ig h tA d d re s s fo r c o rre s p o n d e n c e : O so rio M ig u e l P a rra
R u a A ib i, 7 0
S a o P a u lo - S P - B ra sil- C E P 0 5 0 5 4 -0 1 0
( 2 ,7 ,1 8 ,2 4 ) . T h is r e la tio n te n d s to r e m a in c o n s ta n t th r o u g h a p r o c e s s o f c e ll m u ltip lic a tio n k n o w n a s r e g e n e r a tio n w h ic h is a c tiv a te d w h e n e v e r th e o r g a n lo s e s p a r t o f its m a s s d u e to s u r g ic a l ( h e p a te c to m y ) o r p a th o lo g ic a l ( n e c r o s is ) r e a s o n s . T h e m o s t in tim a te m e c h a n is m s u n d e r ly in g th is c o n tr o l a r e n o t f u lly k n o w n . T h e y in v o lv e m o d if ic a tio n s in th e e x p r e s s io n o f s e v e r a l g e n e s a n d th e a p p e a r a n c e o f m e s s e n g e r R N A a n d its r e s p e c tiv e p r o te in m o le c u le s w h ic h r e p r e s e n t s e v e r a l o th e r f a c to r s h a v in g e ith e r a s tim u la to r y a c tio n s u c h a s h e p a to c y te g r o w th f a c to r ( H G F ) a n d tr a n s f o r m in g g r o w th f a c to r a ( a - G T F ) o r a n in h ib ito r y a c tio n o n th is p r o c e s s s u c h a s tr a n s f o r m in g g r o w th f a c to r ~ ( ~ - T G F ) ( 1 4 ,2 1 ) . I n p r a c tic a l te r m s , th e r e is g e n e r a l a c c e p ta n c e o f th e e x is te n c e o f a n e q u ilib r iu m b e tw e e n liv e r s iz e a n d s u p p ly o f s p la n c h n ic h e p a to tr o p h ic f a c to r s .
P A R R A , a .M .; S ilV A , R .A .P .S .; S ilV A , J.R .M .C . e co ls. - E n h a n ce m e n t o f live r b y stim u la tio n o f in ta ct ra t live r w ith e xo g e n o u s h e p a to tro p h ic fa cto rs
L-threonine 490 m g
L-tryptophan 180 m g
L-valine 530 m g
L-arginine (base) 1060 m g
L-histidine (base) 460 m g
L-alanine 1030 m g
L-asparagine 380 m g
L-aspartic acid 270 m g
L-glutam ic acid 250 m g
L-cystine 30 m g
L-ornithine 260 m g
L-proline 840 m g
L-serine 250 m g
L-tyrosine 160 m g
G lycine 800 m g
D istilled w ater q.s. 100 m l
The follow ing substances w ere added to each 100
m l of the parenteral feeding solution: 12.5 units of regular
insulin (B iobnls-B ioqufm ica do B rasil), 0.125 m g
glucagon (Eli Lilly), 500
Jlg
folic acid, 6.25Jlg
vitam inB 12, 625
Jlg
zinc sulfate, and 250 m g C M C .L-triiodothyronine (T3) 2.26
Ilg/200
g rat w eight inethyl alcohol w as placed separately in each syringe
containing the solution to prevent T3 precipitation in
aqueous m edium from interfering w ith uniform
application.
O n the 8th day, the anim als w ere sacrificed by ether
inhalation after a 24-hour fast and their body and liver
w eights w ere recorded. A liver fragm ent w as obtained,
w eighed im m ediately, identified and frozen for later D N A
m easurem ent.
A nim al m ortality during the experim ent w as recorded
daily after the beginning of the injection schedule and is
reported as percent of the total num ber of anim als in each
group.
The variation in liver w eight enhancem ent in group
B anim als w as calculated at the end of the experim ent as
observed w eight m inus expected w eight divided by
expected w eight. The latter w eight w as determ ined as a
function of anim al body w eight at sacrifice m ultiplied by
the liver w eight/body w eight ratio factor, defined in group
A anim als (control). In sum m ary:
O b s e r v e d - E x p e c t e d
w e ig h t w e ig h t
E x p e c t e d w e ig h t
Previous studies by our group have dem onstrated that
this equilibrium can be broken by exogenous
supplem entation w ith som e know n hepatotrophic factors,
leading to an increase in intact (non-hepatectom ized) liver
size beyond the biologically predeterm ined size(l9,20).
The successive form ulations developed in these studies
have show n an increasing ability to stim ulate a regenerative
enhancem ent of liver size, although at the expense of also
increasing m ortality, thus preventing statistical validation
of the data obtained due to the sm all num ber of surviving
anim als. The objective of the present study w as to confirm
the previous findings using sm all m ethodological
m odifications and a larger num ber of anim als.
MATERIAL AND METHODS
Fem ale W istar rats w eighing approxim ately 200g
w ere divided into tw o groups and housed in cages w ith
food and w ater "ad libitum ". A fter a 24-hour fast, the
anim als w ere identified individually and w eighed and then
injected daily intraperitoneally w ith 40 m l/kg of the
follow ing solutions:
G roup A (control, N
=
10) - Saline solutioncontaining carboxym ethylcellulose (C M C ) at 0.25%
concentration.
G roup B (N
=
20) - a standard solution for parenteralnutrition of the follow ing com position:
G lucose 104 g
Solution containing the am ino acids specified below
200 m l
Pyridoxine 2 m g
C alcium pantothenate 2 m g
Thiam ine 30 m g
R iboflavin phosphate 4 m g
Potassium chloride 1.43 g
Sodium bicarbonate 1.50 g
N icotinam ide 50 m g
M onopotassium phosphate 750 m g
M agnesium sulfate 500 m g
V itam in C 500 m g
D istilled w ater q.S 500 m l
The am ino acid solution em ployed (Soram in 10% ,
D arrow Laborat6rios S.A .), w ith 16
gil
nitrogen, contained:L-phenylalanine 540 m g
L-isoleucine 370 m g
L-leucine 980 m g
L-lysine, acetate 590 m g
L-m ethionine 530 m g
V a r ia t io n ( % ) in liv e r = w e ig h t e n h a n c e m e n t
w h e r e E x p e c t e d
liv e r w e ig h t
B o d y w e ig h t
a t s a c r if ic e x
x 1 0 0
f a c t o r o b t a in e d
f o r g r o u p A
s a o P a u lo M e d ic a l J o u r n a l/ R P M 1 1 3 ( 4 ) : 9 4 1 - 9 4 7 , 1 9 9 5 '\ A R R A , a . M . ; S I L V A , R . A . P . S . ; S I L V A , J . R . M . C . e c o ls . - E n h a n c e m e n t o f liv e r b y s t im u la t io n
9 4 3
B io ch em ical D N A m easu rem en t w as p erfo rm ed after
trich lo ro acetic acid ex tractio n u sin g th e d ip h en y lam in e
reactio n (3 ,1 8 ).
S tatistical an aly sis: T h e resu lts are rep o rted as m ean s
:!:...S E M . D ata fo r th e tw o g ro u p s w ere co m p ared b y th e
M an n -W h itn ey test w h en n ecessary , w ith th e lev el o f
sig n ifican ce set at p < 0 .0 5 .
R E S U L T S
N o m o rtality w as o b serv ed in g ro u p A an im als,
w h ereas m o rtality w as' 6 0 % in g ro u p B , w ith a b ip h asic
p attern : th e first p eak o ccu rred d u rin g th e first tw o d ay s
(3 5 % o f all an im als) an d a seco n d p eak o ccu rred d u rin g
T a b le 1
B o d y a n d liv e r w e ig h ts (g ) a n d liv e r w e ig h t/b o d y w e ig h t ra tio a t th e tim e o f s a c rific e in g ro u p A a n im a ls
B o d y w e ig h t
2 2 7 .2
2 2 1 .2
2 0 3 .6
2 0 2 .8
2 0 1 .2
2 1 5
1 8 2 .5
2 0 0 .4
1 9 4 .5
2 1 5 .4
M e a n
S E M
L iv e r w e ig h t
6 .0 6 4
5 .2 4 2
5 .2 7 1
5 .6 2 5
5 .5 2 6
4 .9 9 0
4 .3 1 3
5 .5 4 4
4 .6 5 5
5 .2 6 3
L iv e r w e ig h t/B o d y w e ig h t
0 .0 2 6 6
0 .0 2 3 6
0 .0 2 5 8
0 .0 2 7 7
0 .0 2 7 4
0 .0 2 3 2
0 .0 2 3 6
0 .0 2 7 6
0 .0 2 3 9
0 .0 2 4 4
0 .0 2 5 4
:t 0 .0 0 0 5
T a b le 2
B o d y a n d liv e r w e ig h ts (g ), liv e r w e ig h t/b o d y w e ig h t ra tio a n d e n h a n c e m e n t o f h e p a tic s iz e (% ) a t th e tim e o f
s a c rific e in g ro u p B a n im a ls
B o d y w e ig h t L iv e r w e ig h t L iv e r w e ig h t/b o d y w e ig h t E n h a n c e m e n t o f liv e r s iz e
2 4 1 .2 1 0 .7 9 3 0 .0 4 4 7 7 6 .1 7
2 0 5 .2 1 0 .5 3 4 0 .0 5 1 3 1 0 2 .1 1
2 0 1 1 0 .3 2 9 0 .0 5 1 4 1 0 2 .3 2
1 9 3 .5 1 0 .3 0 4 0 .0 5 3 3 1 0 9 .6 5
2 0 5 .1 1 1 .1 9 9 0 .0 5 4 6 1 1 4 .9 7
2 1 2 .4 1 1 .9 6 0 0 .0 5 6 3 1 2 1 .6 9
2 2 7 .4 1 3 .9 5 1 0 .0 6 1 4 1 4 1 .5 4
2 0 0 1 2 .4 3 7 0 .0 6 2 2 1 4 4 .8 2
M e a n 0 .0 5 4 4 1 1 4 .1 6
S E M :to .0 0 2 0 :t7 .9 0
P A R R A , a .M .; S IL V A , R .A .P .S .; S IL V A , J .R .M .C . e c o ls . - E n h a n c e m e n t o f liv e r b y s tim u la tio n o f in ta c t ra t liv e r w ith e x o g e n o u s h e p a to tro p h ic fa c to rs
c a lc u la te th e liv e r w e ig h t/b o d y w e ig h t in d e x to b e u s e d
f o r th e d e te r m in a tio n o f e x p e c te d liv e r w e ig h t in g r o u p B
a n im a ls .
T a b le 2 s h o w s th e in d iv id u a l v a lu e s f o r b o d y w e ig h t,
liv e r w e ig h t, liv e r w e ig h t/b o d y w e ig h t r a tio a n d
e n h a n c e m e n t o f h e p a tic s iz e in g r o u p B s u r v iv o r s .
I t s h o u ld b e e m p h a s iz e d th a t tw o o f th e a n im a ls w h o
d ie d , o n e o n th e 6 th a n d th e o th e r o n th e 7 th d a y a f te r th e
b e g in n in g o f th e in je c tio n s , h a v in g e s c a p e d c a n n ib a lis m
o n th e p a r t o f th e s u r v iv o r s , c o u ld b e s u b m itte d to a u to p s y
a n d to th e c a lc u la tio n o f e n h a n c e m e n t o f liv e r s iz e ( T a b le 3 ) .
T a b le 4 s u m m a r iz e s th e r e s u lts a n d th e s ta tis tic a l
c o m p a r is o n s o f D N A m e a s u r e m e n ts in a n im a ls f r o m th e
tw o g r o u p s a t th e tim e o f s a c r if ic e in te r m s o f
c o n c e n tr a tio n s in h e p a tic tis s u e ( m g /g liv e r ) a n d to ta l
D N A /liv e r ( m g ) .
te c to m iz e d ) liv e r s b y s tim u la tio n w ith e x o g e n o u s
h e p a to tr o p h ic f a c to r s h a s b e e n d e m o n s tr a te d in p r e v io u s
s tu d ie s ( 1 9 ,2 0 ) a n d h a s b e e n a ttr ib u te d to a r e g e n e r a tiv e
m e c h a n is m in v o lv in g a n in c r e a s e in h e p a to c y te n u m b e r .
T h e m a jo r d if f ic u lty in th e s tu d y o f in c r e a s e d liv e r
s iz e in e x p e r im e n ts in w h ic h e s tim a te d s iz e is c o m p a r e d
to o b s e r v e d m a s s is to d e te r m in e e s tim a te d s iz e in liv e
a n im a ls . T h is is d o n e in d ir e c tly b y d e f in in g th e liv e r
w e ig h t/b o d y w e ig h t r a tio in a g r o u p o f c o n tr o l a n im a ls .
T h is p r o c e d u r e a ls o tie s th e c a lc u la tio n o f I i v e r g r o w th to
f in a l b o d y w e ig h t, a f a c t th a t e lim in a te s th e p o s s ib le
in f lu e n c e o f tr e a tm e n t w ith g lu c o s e , a m in o a c id s a n d
h o r m o n e s o n v a r ia tio n s in a n im a l a p p e tite , f o o d
c o n s u m p tio n a n d b o d y g r o w th r a te ( 2 0 ) . T h e d if f e r e n c e
b e tw e e n th e m e a n p e r c e n t e n h a n c e m e n t o f liv e r s iz e
o b ta in e d in th e p r e s e n t s tu d y ( 1 1 4 .1 6 : t 7 .9 0 % ) a n d th a t
T a b le 3
B o d y a n d liv e r w e ig h ts (g ) a n d e n h a n c e m e n t o f liv e r s iz e (% ) o f tw o a n im a ls s u b m itte d to n e c ro p s y .
D a y o f d e a th
6 th
7 th
B o d y w e ig h t
1 9 6 .9
1 9 9 .2
L iv e r w e ig h t
1 2 .3 4 5
1 1 .1 6 0
E n h a n c e m e n t o f liv e r s iz e
1 4 6 .8 4
1 2 0 .5 7
T a b le 4
D N A c o n c e n tra tio n s in h e p a tic tis s u e
(mg/g
liv e r) a n d to ta l D N A /liv e r (m g ) a t th e tim e o f s a c rific eG ro u p D N A c o n c e n tra tio n T o ta l D N A
A 2 .4 7 7 1 2 .9 9
:to .0 6 0 :to .4 6
B 1 .7 6 5 2 0 .1 7
:to .1 2 0 :t1 .4 4
p = 0 .0 0 0 5 p = 0 .0 0 0 2
945
FIGURE 1 -
A n im a l m o r t a lit y p r e s e n t in g a b ip h a s ic p r o f ile .o b ta in e d in th e p re v io u s stu d y (6 7 .5 4 :t 1 0 .1 8 % ) (2 0 ) is e sse n tia lly d u e to th e u tiliz a tio n o f a n e w fa c to r fo r th e liv e r w e ig h t/b o d y w e ig h t ra tio (0 .0 2 5 4 ) d e te rm in e d in a sp e c ific g ro u p o f c o n tro l a n im a ls a lso su b je c te d to in tra p e rito n e a l in je c tio n s o f sa lin e so lu tio n . T h e p a in a n d stre ss o f th is p ro c e d u re p ro b a b ly m o d ifie d th ro u g h a n e u ro -h o rm o n a l p a th w a y th is ra tio w h ic h h a d b e e n p re v io u sly c a lc u la te d to b e 0 .0 3 3 in in ta c t a n im a ls( 1 8 ). If th e e n h a n c e m e n t in liv e r m a ss o b ta in e d in th e p re se n t stu d y w e re c a lc u la te d a s a fu n c tio n o f th e 0 .0 3 3 fa c to r (c a lc u la tio n s n o t sh o w n ), th e m e a n w o u ld b e 6 4 .8 4 : t
0 .0 8 % , sim ila r to th a t o b ta in e d p re v io u sly (2 0 ). T h is c h a n g e d e fin ite ly p ro v id e d a c o n tro l g ro u p o f g re a te r sc ie n tific n g o r.
T h e a sso c ia tio n o f th e fa c to rs u se d h e re w ith p o w e rfu l m ito g e n s fo r h e p a to c y te s su c h a s e p id e rm a l g ro w th fa c to r (E G F ) a n d h e p a to c y te g ro w th fa c to r (H G F ), w h ic h h a v e p ro v e d to b e a b le to in d u c e b y th e m se lv e s a n in c re a se in th e siz e o f in ta c t liv e rs in a n im a ls(6 ,1 6 ), m a y p o ssib ly in d u c e a b e tte r re sp o n se , p e rh a p s w ith in a sh o rte r p e rio d o f tim e .
H o w e v e r, th e in c re a se in liv e r g ro w th a c h ie v e d w ith th e m e th o d o lo g ic a l m o d ific a tio n s se q u e n tia lly in tro d u c e d in o u r p re v io u s stu d ie s(1 9 ,2 0 ) w a s a c c o m p a n ie d b y a n a lso in c re a sin g m o rta lity ra te , w ith a b ip h a sic b e h a v io r(2 0 ), i.e ., a first p e a k d u rin g th e first tw o d a y s a fte r th e b e g in n in g o f th e in je c tio n s a n d a se c o n d p e a k d u rin g th e la st tw o d a y s. T h is b e h a v io r w a s re p e a te d in th e p re se n t e x p e rim e n t (F ig . 1 ). T h e tw o p e a k s w e re a ttrib u te d to d iffe re n t c a u se s, th e first b e in g re la te d to a p o ssib le in itia l to x ic ity o f th e
so lu tio n s e m p lo y e d , sin c e it h a d b e e n o b se rv e d th a t a h u m a n m ilk e x tra c t a d d e d to th e so lu tio n a s th e v e h ic le fo r g ro w th fa c to rs p ro te c te d th e a n im a ls(2 0 ). T h is p ro te c tiv e a c tio n w a s c o n firm e d b y th e u se o f d e fa tte d a n d ly o p h iliz e d c o w 's m ilk , b u t w a s a c c o m p a n ie d b y th e o n se t o f n o n -fa ta l c h e m ic a l p e rito n itis in th e a n im a ls th u s tre a te d (u n p u b lish e d d a ta ). F o r th is re a so n , in th e p re se n t stu d y w e trie d c a rb o x y m e th y lc e llu lo se (C M C ) fo r its p ro te c tiv e a c tio n , b u t n o e ffe c tiv e re su lts w e re o b ta in e d . T h e a d m in istra tio n o f th e so lu tio n s in a m o re p h y sio lo g ic a l m a n n e r b y c o n tin u o u s in fu sio n in to th e p o rta l sy ste m , e sp e c ia lly in la rg e r a n im a ls, in to th e p e rito n e a l c a v ity itse lf a n d e v e n fra c tio n a tio n o f th e d o se e m p lo y e d in to m o re th a n o n e d a ily in tra p e rito n e a l in je c tio n m a y p o ssib ly re d u c e th e in itia l m o rta lity o f th e e x p e rim e n ta l a n im a ls.
T h e se c o n d m o rta lity p e a k w ith a n in c re a sin g p a tte rn o b se rv e d d u rin g th e la st d a y s o f th e p re v io u s e x p e rim e n t(2 0 ) a n d a lso in th e p re se n t stu d y , w a s m in im iz e d h e re b y th e re d u c tio n o f th e n u m b e r o f in je c tio n d a y s fro m 1 0 to 7 , so a s to o b ta in a n u m b e r o f su rv iv in g a n im a ls w h o se re su lts c o u ld b e a n a ly z e d sta tistic a lly w ith o u t im p a irm e n t o f liv e r siz e e n h a n c e m e n t. A h ig h ra te o f liv e r g ro w th w a s a lso o b se rv e d in th e a n im a ls th a t d ie d (T a b le 3 ). S tu d ie s a re c u rre n tly u n d e rw a y in o u r la b o ra to ry to d e te rm in e w h e th e r th is la te m o rta lity is re la te d to th e in c re a se in liv e r siz e , a ssu m in g th a t a m a x im u m lim it e x ists fo r re g e n e ra tiv e liv e r g ro w th a n d th a t th is lim it w a s c o n tin u o u sly fo rc e d b y th e e x o g e n o u s h e p a to tro p h ic sti m u l u s a g a i n s t th e b io lo g ic a lly p re d e te rm i n e d e q u ilib riu m .
T h e in c re a se in liv e r siz e w a s a c c o m p a n ie d b y a sig n ific a n t d ilu tio n in tissu e D N A c o n c e n tra tio n , a s in d ic a te d in T a b le 4 . S in c e th e re p o rt b y H IG G IN S & A N D E R S O N ( 1 1 ), it h a s b e e n k n o w n th a t th e p a re n c h y m a g a in s tlu id d u rin g th e la te sta g e s o f re g e n e ra tio n . S u c h a g re a t in c re a se in liv e r siz e , a lth o u g h a c c o m p a n ie d b y so m e d e g re e o f v a ria tio n in tissu e c o m p o sitio n , d o e s n o t se e m to in v a lid a te o u r in te rp re ta tio n th a t its c a u se is m a in ly th e fo rm a tio n o f n e w c e lls, in v ie w o f th e g re a t a n d sig n ific a n t in c re a se in to ta l D N A m a ss p e r liv e r (fro m 1 2 .9 9 m g to 2 0 .1 7 m g , p
=
0 .0 0 0 2 ). A stu d y o f th e v a ria tio n s in tissu e c o m p o sitio n m a y b e tte r e lu c id a te th is d e ta il.T h e d iffic u lty in m a in ta in in g th e p o rta l v e in c a th e te riz e d fo r o n e w e e k in sm a ll a n im a ls w a s o b v ia te d b y a p p ly in g th e so lu tio n s u n d e r stu d y in tra p e rito n e a lly , a lth o u g h a c c e p tin g so m e sy ste m ic a b so rp tio n th ro u g h th e a b d o m in a l w a ll. It h a s b e e n d e m o n stra te d th a t e x o g e n o u s h e p a to tro p h ic fa c to rs h a v e th e h ig h e st e ffe c t w h e n in tro d u c e d th ro u g h th e p o rta l v e in , m im ic k in g th e ir p h y sio lo g ic a l ro u te , w h e n c o m p a re d to a d m in istra tio n th ro u g h a p e rip h e ra l v e in ( 1 9 ). W e c o n sid e r th is o b se rv a tio n
7
6
5
4 3
2
D a y s a f t e r 1 s t in je c t io n
2 5
2 0
~
e -
1 5~
:E
0 1 0
:E
5
0
0
P A R R A , a . M . ; S I L V A , R . A . P . S . ; S I L V A , J . R . M . C . e c o ls . - E n h a n c e m e n t o f liv e r b y s t im u la t io n
o f in t a c t r a t liv e r w it h e x o g e n o u s h e p a t o t r o p h ic f a c t o r s
re g e n e ra tiv e s tim u lu s (l ,5 ,8 , 1 5 ,2 3 ).
W e b e lie v e th a t th e p e rs p e c tiv e o f s tim u la tin g liv e r re g e n e ra tio n b y th e a d m in is tra tio n o f h e p a to tro p h ic fa c to rs b y th e p o rta l ro u te h a s g re a t c lin ic a l a p p lic a b ility b o th in s itu a tio n s o f re d u c e d liv e r s iz e a fte r h e p a te c to m y o r h e p a to c y te n e c ro s is (h e p a titis a n d a b s c e s s e s ) a n d in
a g re a te r re s id u a l liv e r m a s s . A ls o , p a tie n ts w ith c irrh o s is , in w h o m re g e n e ra tiv e s tim u la tio n b y p a rtia l h e p a te c to m y h a s b e e n s h o w n to p ro d u c e a h is to lo g ic a l a n d fu n c tio n a l im p ro v e m e n t(4 ,9 ,1 0 ,1 2 ,1 3 ,1 7 ,2 2 ) m a y b e n e fit fro m th is m e th o d w ith o u t th e in c o n v e n ie n c e o f re d u c e d fu n c tio n b ro u g h t a b o u t b y h e p a te c to m y .
RESUMO
O bjetivos: C onfirm ar observayoes anteriores (P A R R A e col. 1 9 .2 0 ) que sugeriam a possibilidade de fazer crescer 0 ffgado em
anim ais intactos, por estfm ulo hepatotr6fico ex6geno, ultrapassando seu tam anho biologicam ente pre-determ inado. M aterial
e M etodos: D ois grupos de fem eas de ratos W istar, foram injetadas diariam ente na cavidade peritoneal (40 m l/kg) por sete
dias consecutivos com as seguintes soluyoes: G R U P O A (controle) - soluyao salina com carboxim etilcelulose (C M C ) a 0.25% ;
G R U P O B - soluyao de fatores hepatotr6ficos ex6genos constitufda de glicose, am inockidos, insulina, glucagon, vitam ins,
eletr6litos, triiodotironina e C M C na m esm a concentrayao do grupo controle. N o oitavo dia os anim ais foram sacrificados e
avaliados os seguintes param etros: variayao da m assa hepatica e D N A total do ffgado dos anim ais do grupo experim ental em
relayao ao grupo controle. R esultados: Foi observado crescim ento da m assa hepatica de 114,16:t 7,9% acim a do esperado
e aum ento do D N A total hepatico de 12,99 :t 0,46 m g para 20,17 por ffgado (p=0.0002). C onclusao: 0 aum ento do tam anho
do ffgado a partir de sua m assa prim itiva, estim ulada por fatores hepatotr6ficos ex6genos, pode vir a ter aplicayoes em
hepatologia, com o em casos de cirroses revertendo parcialm ente as alterayoes, histol6gicas e funcionais, ou em transplantes
intre-vivos, criando m aior m assa hepatica a ser dividida entre doador e receptor.
947
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