Lipid peroxidation and extracellular matrix in normal and cirrhotic rat livers following 70% hepatectomy

The aim was to measure the deposition of collagens and proteoglycans and the underlying mechanism leading to lipid peroxidation due to oxidative stress in partially hepatectomized normal and cirrhotic rats.

Four groups of adult Wistar rats were used comprising normal livers, regenerated normal livers, cirrhotic livers, and regenerated cirrhotic livers. Cirrhosis was induced by intragastric administration of carbon tetrachloride and phenobarbital in the drinking water of the rats. Hydroxyproline, as a constituent of collagens, uronic acid, as a constituent of proteoglycans, and malondealdehyde, an end-product of lipid peroxides, were measured in normal and cirrhotic rats, and following partial hepatectomy.

Hydroxyproline, uronic acid and malondealdehyde levels were 234.2 +/- 41.2, 11.82 +/- 1.92, 46.3 +/- 5.8 and 211.8 +/- 43.6, 9.16 +/- 1.41, 48.5 +/- 7.5 for normal and regenerated normal livers respectively. The values after partial hepatectomy in cirrhotic and regenerated cirrhotic livers were 396.9 +/- 48.5, 17.96 +/- 1.62, 144.5 +/- 25.1 and 309.6 +/- 43.2, 13.35 +/- 1.72, 229.9 +/- 24.4, respectively. When the cirrhotic liver group was compared with the normal liver group, the levels of hydroxyproline, uronic acid and malondealdehyde were significantly higher (p < 0.001). Uronic acid levels of regenerated normal and regenerated cirrhotic livers and hydroxyproline level of regenerated cirrhotic liver were significantly less than those of their non-regenerated states (p < 0.01). Although the malondealdehyde levels of normal and regenerated normal livers did not differ significantly (p > 0.05), the malondealdehyde levels of regenerated cirrhotic liver was significantly higher than cirrhotic liver (p < 0.01). The histopathological examination with light microscopy did not reveal any obvious difference between the groups other than between normal and cirrhotic.

Cirrhotic livers revealed a significantly higher amount of extracellular matrix constituents and lipid peroxidation than normal livers. Although partial hepatectomy in cirrhotic livers caused decreases in the tissue levels of collagens and proteoglycans, it did not actually lower the ongoing oxidative stress, known as physiological lipid peroxidation, in normal and cirrhotic livers following partial hepatectomy.