Abstract
Oxidants have been shown to be involved in alcoholinduced
liver injury. This study was designed to test
the hypothesis that the antioxidant polyphenolic extract
of green tea, comprised predominantly of epigallocatechin
gallate, protects against early alcoholinduced
liver injury in rats. Male Wistar rats were fed
highfat liquid diets with or without ethanol (10 14 g
kg 1 day 1) and green tea (300 mg kg 1 day 1) continuously
for 4 weeks using an intragastric enteral feeding
protocol. Mean body weight gains (~4 g/day) were
not significantly different between treatment groups,
and green tea extract did not the affect average concentration
or the cycling of urine ethanol concentrations
(0 550 mg dl 1 day 1). After 4 weeks, serum ALT
levels were increased significantly about 4-fold over
control values (35±3 IU/l) by enteral ethanol (114±18);
inclusion of green tea extract in the diet significantly
blunted this increase (65±10). Enteral ethanol also
caused severe fatty accumulation, mild inflammation,
and necrosis in the liver. While not affecting fat accumulation
or inflammation, green tea extract significantly
blunted increases in necrosis caused by
ethanol. Furthermore, ethanol significantly increased
the accumulation of protein adducts of 4-hydroxynonenal,
a product of lipid peroxidation and an index
of oxidative stress; green tea extract blocked this effect
almost completely. TNFa protein levels were increased
in liver by alcohol; this phenomenon was also
blunted by green tea extract. These results indicate
that simple dietary antioxidants, such as those found
in green tea, prevent early alcoholinduced liver injury,
most likely by preventing oxidative stress.
Attenuation of sepsis-induced rat liver injury by epigallocatechin gallate via suppression of oxidative stress-related inflammation
