PubMed · 14269663
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J R HOFSTETTER. 1965. [LIVER TESTS].. https://pubmed.ncbi.nlm.nih.gov/14269663/
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Oxidative stress is involved in the pathogenesis of chemically mediated liver injury. Since glycosaminoglycans possess antioxidant activity, the aim of this work was to assess the protective effects of hyaluronic acid and chondroitin-4-sulphate treatment in a model of carbon tetrachloride-induced liver injury. Liver damage was induced in male rats by an intraperitoneal injection of carbon tetrachloride (1 ml/kg in vegetal oil). Serum alanine aminotransferase and aspartate aminotransferase, hepatic malondialdehyde, plasma TNF-alpha, hepatic reduced glutathione and catalase, and myeloperoxidase, an index of polymorphonuclear infiltration in the jeopardised hepatic tissue, were evaluated 24 h after carbon tetrachloride administration. Carbon tetrachloride produced a marked increase in serum alanine aminotransferase and aspartate aminotransferase activities, primed lipid peroxidation, enhanced plasma TNF-alpha levels, induced a severe depletion of reduced glutathione and catalase, and promoted neutrophil accumulation. Intraperitoneal treatment of rats with hyaluronic acid (25 mg/kg) or chondroitin-4-sulphate (25 mg/kg) failed to exert any effect in the considered parameter, while the combination treatment with both glycosaminoglycans (12,5 + 12,5 mg/kg) decreased the serum levels of alanine aminotransferase and aspartate aminotransferase, inhibited lipid peroxidation by reducing hepatic malondialdehyde, reduced plasma TNF-alpha, restored the endogenous antioxidants, and finally decreased myeloperoxidase activity. These results suggest that hyaluronic acid and chondroitin-4-sulphate possess a different antioxidant mechanism and consequently the combined administration of both glycosaminoglycans exerts a synergistic effect with respect to the single treatment.
AIM: Estradiol treatment regulates estrogen receptor (ER) level in normal rat liver. However, little information is available concerning the role of estrogen in regulating liver ER in hepatic fibrosis in rats. The present study was conducted to determine whether estradiol treatment in CCl4-induced liver fibrosis of female and ovariectomized rats altered liver ERalpha and its mRNA expression, and to investigate the possible mechanisms. METHODS: Seventy female rats were divided into seven groups with ten rats in each. The ovariectomy groups were initiated with ovariectomies and the sham operation groups were initiated with just sham operations. The CCl4 toxic fibrosis groups received 400 mL/L CCl4 subcutaneously at a dose of 2 mL/kg twice weekly. Estrogen groups were treated subcutaneously with estradiol 1 mg/kg, the normal control group and an ovariectomy group received injection of peanut oil vehicle twice weekly. At the end of 8 weeks, all the rats were killed to detect their serum and hepatic indicators, their hepatic collagen content, and liver ER and ER mRNA expression. RESULTS: Estradiol treatment in both ovariectomy and sham ovariectomy groups reduced liver levels of ALT (from 658 +/- 220 nkat/L to 311 +/- 146 nkat/L and 540 +/- 252 nkat/L to 314 +/- 163 nkat/L, P<0.05) and AST (from 697 +/- 240 nkat/L to 321 +/- 121 nkat/L and 631 +/- 268 nkat/L to 302 +/- 153 nkat/L, P<0.05), increased serum nitric oxide (NO) level (from 53.7 +/- 17.1 micromol/L to 93.3 +/- 24.2 micromol/L and 55.3 +/- 23.1 micromol/L to 87.5 +/- 23.6 micromol/L, P<0.05) and hepatic nitric oxide synthase (NOS) activity (from 1.73 +/- 0.71 KU/g to 2.49 +/- 1.20 KU/g and 1.65 +/- 0.46 KU/g to 2.68 +/- 1.17 KU/g, P<0.05), diminished the accumulation of hepatic collagen, decreased centrolobular necrotic areas as well as the inflammatory reaction in rats subjected to CCl4. The positive signal of ER and ER mRNA distributed in parenchymal and non-parenchymal hepatic cells, especially near the hepatic centrolobular and periportal areas. Ovariectomy decreased ER level (from 10.2 +/- 3.2 to 4.3 +/- 1.3) and ER mRNA expression (from 12.8 +/- 2.1 to 10.9 +/- 1.3) significantly (P<0.05). Hepatic ER and ER mRNA concentrations were elevated after treatment with estradiol in both ovariectomy (15.8 +/- 2.4, 20.8 +/- 3.1) and sham ovariectomy (18.7 +/- 3.8, 23.1 +/- 3.7) fibrotic groups (P<0.05). CONCLUSION: The increase in hepatic ER and mRNA expression may be part of the molecular mechanisms underlying the suppressive effect of estradiol on liver fibrosis induced by CCl4 administration.
This study investigated the protective effects of acteoside, a phenylethanoid glycoside, on the carbon tetrachloride-induced hepatotoxicity as well as the possible mechanisms involved in this protection in mice. Pretreatment with acteoside prior to the administration of carbon tetrachloride significantly prevented the increased serum enzymatic activities of alanine and aspartate aminotransferase in a dose-dependent manner. In addition, pretreatment with acteoside significantly prevented the increase in hepatic malondialdehyde formation and the depletion of the reduced glutathione content in the liver of carbon tetrachloride-intoxicated mice. Carbon tetrachloride-induced hepatotoxicity was also essentially prevented, as indicated by a liver histopathologic study. The effects of acteoside on cytochrome P450 (P450) 2E1, the major isozyme involved in carbon tetrachloride bioactivation were also investigated. Treatment of the mice with acteoside resulted in a significant decrease in the P450 2E1-dependent pnitrophenol and aniline hydroxylation in a dose-dependent manner. Consistent with these observations, the P450 2El protein levels were also lower. Acteoside exhibited anti-oxidant effects on FeCl2-ascorbate induced lipid peroxidation in a mouse liver homogenate, and on superoxide radical scavenging activity. These results suggest that the protective effects of acteoside against the carbon tetrachloride-induced hepatotoxicity possibly involve mechanisms related to its ability to block the P450-mediated carbon tetrachloride bioactivation and free radical scavenging effects.