Abstract: Objective To study the effects of Jinmaitong Capsule (JMT) on the expressions of nuclear factor-E2-related factor 2 (Nrf2) and haem oxygenase-1 (HO-1) and their mRNAs in dorsal root ganglion (DRG) and the level of plasma carbon monoxide (CO) in STZ-induced diabetic rats. Method STZ-induced diabetic rats were randomly divided into 5 groups including model group, low-dose JMT group, middle-dose JMT group, high-dose JMT groupand Thioctic Acid Capsule (TAC) group. Ten normal rats matching with weight and age served as the control group. All rats were given intragastric administration for 12 weeks and then culled. The mechanical withdrawal threshold was tested by electronic Von Frey instrument before death. The expressions of Nrf2 and HO-1 and their mRNAs in DRG were detected by SABC immunohistochemical method and real-time fluorogenetic quantitative PCR respectively. And the content of plasma COHb was also measured. Result Compared with the control group, the mechanical withdrawal threshold, the content of plasma CO and the expressions of Nrf2 and HO-1 and their mRNAs in DRG of all the diabetic rats groups decreased significantly (p<0.01). All the above-mentioned indexes in treatment groups raised strikingly (p<0.05 or p<0.01). The middle-dose JMT group was more effective than the TAC group in enhancing the expression of HO-1 in DRG (p<0.05). Conclusion Jinmaitong Capsule can ameliorate the peripheral neuropathic pain of STZ-DM rats by enhancing the expressions of Nrf2, HO-1 and CO in DRG.

Key words: diabetic peripheral neuropathy, nuclear factor-E2-related factor 2, haem oxygenase-1, carbon monoxide, Jinmaitong capsule