Effects of dietary corn bran hemicellulose and neomycin on hepatic caspase-3 activity and glycoprotein concentration in rats treated with or without D-galactosamine.

The effects of dietary corn bran hemicellulose (CBH) and neomycin (Neo) on hepatic caspase-3 activity and glycoprotein concentration were investigated to explore the possible mechanism of the alleviative action of dietary CBH and Neo on the development of D-galactosamine (GalN)-hepatitis. Rats were fed a diet containing 5% CBH with or without neomycin (Neo) for 7 or 14 d. On the last day of feeding, the rats were treated with GalN (400 mg/kg body weight, i.p.), and their plasma transaminase activities, hepatic glycoprotein concentrations and hepatic caspase-3 activities were determined 6 or 24 h later. Although the elevations of plasma transaminase activities were suppressed by CBH or Neo 24 h after GalN-treatment, the activities were not affected by CBH or Neo at an early stage (6 h) of GalN action. At 6 h, hepatic caspase-3 activity was elevated by CBH diet alone as high as that of the GalN-injected control-diet group, and the activity was not elevated further by GalN. At the same time, both GalN-treatment and CBH feeding reduced the hepatic glycoprotein (Mw. 64,000-74,000) concentration, but Neo did not affect the caspase activity or the glycoprotein concentration. These results suggest that dietary CBH elevates hepatic caspase-3 activity and reduces hepatic glycoprotein concentration, and may imply that CBH would suppress GalN-hepatitis not at the early- or middle-step of apoptosis but at the late-step of apoptosis or necrosis, although the relation between these phenomena and the alleviative effects of CBH and Neo on GalN-induced hepatitis is yet to be clarified.