Studies on the hyperplasia (‘regeneration’) of the rat liver following partial hepatectomy. Changes in lipid peroxidation and general biochemical aspects

Abstract

Using the experimental model of partial hepatectomy in the rat, we have examined the relationship between cell division and lipid peroxidation activity. In rats entrained to a regime of 12 h light/12 h dark and with a fixed 8 h feeding period in the dark phase, partial hepatectomy is followed by a rapid regeneration of liver mass with cycles of synchronized cell division at 24 h intervals. The latter phenomenon is indicated in this study by pulses of thymidine kinase activity having maxima at 24 h, 48 h and 72 h after partial hepatectomy. Microsomes prepared from regenerating livers show changes in lipid peroxidation activity (induced by NADPH/ADP/iron or by ascorbate/iron), which is significantly decreased relative to that in microsomes from sham-operated controls, again at 24 h, 48 h and 72 h after the operation. This phenomenon has been investigated with regard to possible underlying changes in the content of microsomal fatty acids, the microsomal enzymes NADPH:cytochrome c reductase and cytochrome P-450, and the physiological microsomal antioxidant alpha-tocopherol. The cycles of decreased lipid peroxidation activity are apparently due, at least in part, to changes in microsomal alpha-tocopherol content that are closely associated in time with thymidine kinase activity.

Inhibitory Effect of Vitamin E Administration on the Progression of Liver Regeneration Induced by Partial Hepatectomy in Rats

“…1B). Microsomal LP was decreased at early PH times as previously found (Aguilar-Delfín et al, 1996;Slater et al, 1990). Vitamin E treatment of these animals promoted a drastic de-…”

“…Previous reports indicate that the reduced microsomal LP rate coincides with an increased content of ␣-tocopherol, and the latter is also associated in time with higher activity of thymidine kinase in livers obtained from PH rats (Cheeseman et al, 1986b;Slater et al, 1990). Increased LP content has been shown in the regenerating liver of rats maintained on a vitamin E-deficient diet, suggesting that vitamin E plays a leading role in the defense system and that LP is largely concerned with liver regeneration (Tanaka et al, 1996).…”

“…Plasma membranes from regenerating liver have an increased content of lipid-soluble chain-breaking antioxidants, such as ␣-tocopherol (Slater et al, 1990). An analogous situation has been observed to occur in active proliferating liver tumors (Cheeseman et al, 1986a).…”

Természetes hatóanyagok a májterápiában

“…Slater munkásságához kötődik a májterápiában alkalmazott (+)-cianidanol-3 katechin típusú antioxidáns vegyület, amely Catergen néven hazánkban is forgalomban volt [18]. A gyógyszert később, halálos kimenetelű haemolyticus anaemiát okozó hatása miatt bevonták.…”

The effects of quercetin on liver regeneration after liver resection in rats

“…Hepatic lipid peroxidation peaks at 24 h after PH when GSH content is minimum [1,14,16]. It has also been addressed that oxidative stress is reduced before cell division [2,6,46]. Increased oxidative stress could diminish the regeneration process.…”