| Objective To explore the differences and pathogenesis ofhepatotoxicity induced by chronic treatment of valproic acid (VPA) ininfant age, and in combination administration with inducers of liverenzyme, as well to investigate their protection of L-carnitine andmitochondrial targeted antioxidants against the side effect. Methods Animal model was established by oral administrationchronically with VPA at doses of 200 or 500 mg/kg/day in 30 days for 112infant(21 days) and adult Wistar rats. The rats were grouping as following:T0 = controls, T1 = low dose VPA, T2 = low dose VPA + PB( Phenobarbital ,PB 20mg/Kg), T3 = high dose VPA , T4= high dose VPA +PB, T5= high dose VPA + L-carnitine (200mg/kg/day), T6= high dose VPA+ PB + L-carnitine, T7= high dose VPA + VitE (100mg/kg/day) + CoQ10(20mg/kg/day) and T8 = high dose VPA+ PB+VitE+CoQ10. Mitochondriaof hepatocytes was obtained by differential centrifugation. (1) The levels ofliver enzymes, serum lipid, coagulation factors, plasma ammonia andL-carnitine in sera as well as the changes of respiratory enzymes and lipidperoxidation in hepatic mitochondria were detected by chromatometry; (2)VPA and PB serum levels, MMP and mRNA expression of CYP450reductase in mitochondria were determined by HPLC, flow cytometer or insitu hybridization respectively; (3) Morphology of hepatocytes wasobserved by microscopy with HE & Oil-Red-O staining, and theirmitochondria by electron microscopy. Results (1) The range of VPA serum levels in most rats was within52 to 87.7μg/ml and the maximum was 160μg/ml, which was comparablewith therapeutic concentration in clinic. VPA serum levels were loweddown by 30.88% to 47.02% due to the combination with PB. It wasindicated that the metabolism of VPA was accelerated by PB; (2) In all ratstreated with high dose VPA added with PB or not, there were no significantelevations of liver enzymes (ALT and AST), total cholesterol (CHO),triglycerides (TG), high density lipoprotein(HDL) or low densitylipoprotein cholesterol (LDLc). However significant abnormalities infunction of blood coagulation and serum fibrinogen were shown, and thelevels of plasma ammonia and L-carnitine also changed significantly. 7Furthermore, compared with controls, no alteration of coagulation functionand ammonia level in blood had been found in T5or T6 since L-carnitinesupplementation, while only liver coagulation function was effectivelyprotected with VitE+CoQ10 from high dose VPA added with PB or not inthe two age groups either; (3) Average content of cytochrome aa3 in livermitochondria of infant rats were reduced by 58.80% and 61.80% becauseof administration of high dose VPA and high dose VPA added with PB, butwere reduced by 37.55% and 46.53% in adults. The protection against theloss of cytochrome aa3 by coadministration of VitE and CoQ10 was obvious,yet there appeared no protection with L-carnitine supplementation. As foractivities of SDH, which affected by high dose VPA in infants, weresignificant decreased by 44.8% and 57.9%, respectively, but still in normalrange in adult groups. Activities of CCO in liver mitochondria weresignificantly lowered by high dose VPA or added with PB in T3 and T4compared with T0(P<0.01)in both age groups. However activities of SDHand CCO were effectively protected by L-carnitine or coadministration ofVitE and CoQ10; (4) Compared with T0, levels of glotathione-SH (GSH) inliver mitochondria were significantly decreased both in infant and adultrats treated with high dose VPA or added with PB(P<0.01), whereas thelevels of malondialdehyde(MDA) were significantly increased in both agegroups(P<0.05).There was much severe in infant either GSH or MDA. The 8levels of GSH and MDA in mitochondria were still normal in T7and T8dueto treatment with VitE and CoQ10;(5) MMP of mito...
|
PDF Full Text Request