OBJECTIVETo study the possible pathogenic mechanism of liver injury in type 2 diabetes mellitus (T2DM) and the intervening effect of puerarin on it.

METHODSMice with T2DM (KKAy) were randomly divided into two groups, the model group and the puerarin group. And the C57BL/J mice of the same age were set up as normal controls. They were sacrificed at 28 weeks old for observing serum fasting blood glucose (FBG), triglyceride (TG), total cholesterol (TC), alanine aminotransferase (ALT), aspartate aminotransferase (AST) by automatic biochemistry; liver cell apoptosis by flow cytometry; pathomorphology by electron microscope; and mRNA expressions of bcl-2 and bax genes by RT-PCR; as well as the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), Na(+)-K(+)-ATPase; and content of malondialdehyde (MDA) in liver tissue by spectrophotometer.

RESULTSIn KKAy mice, blood levels of FBG, TG, TC, ALT, AST and liver cell apoptosis rate were higher; the bax mRNA expression was higher and bcl-2 mRNA was lower markedly; the activities of SOD, GSH-Px, Na(+)-K(+)-ATPase in liver tissue were lower, and MDA content was higher than those in the normal control significantly (all P <0.01). Besides, mitochondria swelling and damage were found in liver tissue. While in the puerarin group after treatment, all the above-mentioned changes were alleviated to some extent.

CONCLUSIONSObvious liver injury emerges in KKAy mice. Puerarin shows a protective effect on the T2DM caused oxidative damage by way of up-regulating bcl-2 to inhibit oxidative stress, and improving the energy metabolic dysfunction in liver of mice.