Effects of baicalin on diabetic neuropathic pain involving transient receptor potential vanilloid 1 in the dorsal root ganglia of rats.

Diabetic peripheral neuropathy is the most common complication of diabetes mellitus and leads to sensory symptoms, including diabetic neuropathic pain (DNP). DNP is a major public health problem because it has a considerable impact on life quality of diabetes mellitus patients. Therefore, development of novel effective analgesics for DNP relief and treatment is warranted. Transient receptor potential vanilloid 1 (TRPV1) has a crucial role in nociceptive transmission under pathological forms of pain. Baicalin is a flavonoid compound extracted from a medicinal herb, Huang Qin, it possesses antioxidant properties and has an analgesic effect on nitroglycerin-induced migraine in rats and neuropathic pain in spinal nerve ligation rats. However, the effects of baicalin on DNP are unclear. Therefore, the aim of this study is to examine the effects of baicalin on DNP. Our data show that a single dose of baicalin (40 µg/kg) had a transient analgesic effect on streptozotocin (STZ)-induced DNP rats. Moreover, cumulative injection of baicalin prevented the development of STZ-induced DNP in rats in a dose-dependent manner. In addition, baicalin dose-dependently suppressed the expression of TRPV1 in dorsal root ganglia of STZ-induced DNP rats. Therefore, the analgesic role of baicalin in DNP probably occurred through TRPV1. Baicalin may play an important analgesic role in DNP and might serve as a potential compound in clinical treatment and prevention of DNP.