The protective in vivo effects of
melatonin or
pinoline on
carbon tetrachloride (CCl(4))-induced oxidative damage were investigated in liver of rats and compared to rats injected only with CCl(4) (5 mL/kg
body weight). Hepatic cell membrane fluidity, monitored using fluorescence spectroscopy, exhibited a significant decrease in animals exposed to CCl(4) compared to control rats. Increases in
lipid and
protein oxidation, as assessed by concentrations of
malondialdehyde (MDA) and 4-hydroxyalkenals (4-HDA), and protein carbonylation, respectively, were also seen in hepatic homogenates of animals exposed to CCl(4). The administration of
melatonin (10 mg/kg
body weight) or
pinoline injected 30 min before and 1 hr after CCl(4), fully prevented membrane rigidity and
protein oxidation. However, treatment with
melatonin was more effective in terms of reducing lipid peroxidation than
pinoline, as the increases in MDA+4-HDA levels because of CCl(4) were reduced by 93.4% and 34.4% for
melatonin or
pinoline, respectively. Livers from CCl(4)-injected rats showed several histopathological alterations; above all, there were signs of
necrosis and ballooning degeneration. The concurrent administration of
melatonin or
pinoline reduced the severity of these morphological changes. On the basis of the biochemical and histopathological findings, we conclude that both
melatonin and
pinoline were highly effective in protecting the liver against oxidative damage and membrane rigidity because of CCl(4). Therefore, these
indoles may be useful as cotreatments for patients with hepatic intoxication induced by CCl(4).