Anti-diabetes effects and mechanisms of a Chinese herbal medicine preparation JQ-R in diabetic KKAy mice and in vitro

摘要

OBJECTIVE To investigate the effects and mechanisms by which JQ-R regulated the glucose metabolism and improves insulin sensitivity in diabetic KKAy mice and insulin-resistant L6 myotubes. JQ-R is a mixture of refined extracts from Coptis chinensis, Astragalus membranaceus and Lonicera japonica, three major herbs of JinQi-JiangTang tablet. METHODS Diabetic KKAy mice were adminis-tered JQ-R (100 mg·kg-1or 200 mg·kg-1BW) for 10 weeks. Levels of fasting plasma glucose, lipids, insulin and hemoglobin A1c were monitored.Systemic insulin sensitivity was quantified using the eugly-cemic clamp.The effect of JQ-R on the expressions of the enzymes involved in insulin signaling,oxidative stress and inflammation(Akt,NFκB,IΚBα, JNK, Erk, p38 MAPK) were measured in L6 insulin-resis-tant myotubes. RESULTS JQ-R showed beneficial effects on glucose homeostasis and insulin sensi-tivity in diabetic KKAy mice after 10 weeks treatment. JQ-R also ameliorated the plasma lipid profiles. Moreover,JQ-R can directly reverse the decreased activity of SOD and increased MDA levels as well as activity of iNOS in insulin resistant L6 cell induced with palmitic acid(PA).The expressions of phos-phorylation of NF-κB p65,IκBα,JNK1/2 and Erk1/2 were also decreased after JQ-R treatment.It was also shown that the insulin-stimulated glucose uptake increased significantly after JQ-R treatment,with upregulated expression of phosphorylation of Akt. CONCLUSION JQ-R ameliorated the glucose and lipid metabolism and insulin sensitivity in diabetic KKAy mice. In vitro treatment with JQ-R directly enhanced insulin stimulated glucose uptake in insulin resistant myotubes with improved insulin signal-ling and inflammatory response and oxidative stress state.