Ascorbic acid concentrations in dimethylnitrosamine-induced hepatic fibrosis in rats

Ascorbic acid is a potent antioxidant and is involved in many metabolic activities including collagen biosynthesis. In the present investigation, ascorbic acid and lipid peroxides were monitored in the blood and liver samples during the progression of experimentally induced hepatic fibrosis.

Liver injury was induced by intraperitoneal injections of dimethylnitrosamine (DMN) on three consecutive days of every week over a period of 21 days. The progression of fibrosis was assessed by histopathological examination and by monitoring of the collagen content of the liver tissue. Ascorbic acid and lipid peroxides were monitored in both blood and liver samples on days 0, 7, 14, and 21 after the start of DMN administration. The liver total protein was also measured during the investigation.

Histopathological examination demonstrated centrilobular necrosis, fibrosis, and early cirrhosis during DMN treatment. The collagen content increased four-fold on the 21st day of investigation. Lipid peroxides were elevated significantly in both blood and liver specimens on days 7, 14, and 21. A drastic decrease was observed in the ascorbic acid concentrations in both liver and blood samples on all days after the start of DMN administration. Liver total protein concentrations were significantly reduced during DMN administration.

The exact mechanism of the decrease of ascorbic acid during DMN-induced hepatic fibrosis is not clear. The most probable reason for the decreased blood and liver ascorbic acid during DMN-induced hepatic fibrosis is the increased utilization of ascorbic acid for free radical scavenging in order to reduce the highly elevated oxidative stress.