Ácidos graxos ômega-3 e ômega-6, dimetilsulfóxido e ternatina na regeneração hepática e no estresse oxidativo em ratos

Abstract

The liver exhibits a remarkable regenerative capacity after tissue damage, including partial hepatectomy. Reactive oxygen species and lipid peroxidation have been implicated as control mechanisms of cellular growth and proliferation. Dimethylsulfoxide (DMSO) and ternatin (TRT), known free radical scanvengers, and the w-3 and w-6 polyunsaturated fatty acids (PUFA) were evaluated in an experimental model to assess their influence on rat liver regeneration and oxidative stress. One hundred and eight male Wistar rats were randomly assigned to six groups which contained 18 animals each. Group 01 (G1) was the control group: rats were just submitted to laparotomy (without partial hepatectomy) at the time T0. All the others groups, besides Higgins-Anderson partial hepatectomy (HP) at time T0, received daily for fourteen days, by intraperitoneal (i.p.) route, one of the following exogenous drug: G2 got NaCl 0.9% (saline) 0.1mL/kg,, G3 receveid w-3 PUFA 0.1g/kg, G4 TRT 1.0mg/kg, G5 DMSO 3.3mg/kg, and G6 w-6 PUFA 0.1g/kg. In each group, at the time 36h(T1), 168h(T2) and 336h(T3) post-HP, a subgroup of six rats was chosen in a randomized way to complementary hepatectomy (in G1 a total hepatectomy was performed), when blood and the liver residual posterior lobes were taken to studies and exams. All surgical procedures were performed under inhalatory ether anesthesia. Thiobarbituric acid reactive substances (TBARS) and reduced glutathione (GSH) were measured in plasma and in liver tissue. Blood concentrations of glucose, total bilirubin, and serum glutamic pyruvic transaminase (SGPT,alanine transaminase) were also evaluated as indicators of hepatic damage and organic homeostasis liver-dependent. Data were first submitted to Kruskal-Wallis test to verify the approximate normality of the distributions and then they were analyzed: liver weight evolution via analysis of regression and t test of Student and all others parameters by mean + S.E.M. and comparative test of Dunnett: p<0.05 was accepted as statistically significant. TRT, DMSO and PUFA w-3 inhibited the liver regeneration. PUFA w-6, on the contrary, did not show inhibitory effect. Lipid peroxidation got higher in blood and in liver after the administration of w-6. DMSO, TRT, and PUFA w-3 induced a reduction on hepatic GSH concentration 7 days post-HP. The results of the present study reinforce the hypothesis that oxidative stress plays an important role on rat liver regeneration phenomenon after partial hepatectomy.