Evaluation of Juanbi Tongluo Oral Liquid on Improving Sciatic Neuronal Apoptosis in Type 2 Diabetic Model Mice

OBJECTIVE To evaluate the ameliorative effect of Juanbi Tongluo Oral Liquid on sciatic neuronal apoptosis in Type 2 diabetic model mice.

METHODS The Type 2 diabetes mouse model was established by feeding with high-fat and high-sugar diet combined with intraperitoneal injection of streptozotocin (STZ). The mice were treated with metformin (200 mg ·kg^-1·d^-1), low dose (3.9 g ·kg^-1·d^-1) and high dose (7.8 g ·kg^-1·d^-1) Juanbi Tongluo Oral Liquid for 35 days. The latency of response to thermal stimulation was detected by hot plate, and the values of blood glucose insulin and glycosylated hemoglobin were determined. Biochemical kits were used to detect the expression of serum total cholesterol (T-CHO), triglyceride (TG), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) and oxidation product malondialdehyde (MDA). The expression of tumor cytokine α (TNF-α), interleukin (IL)-1β, IL-6 and IL-10 in serum of mice were detected by ELISA method; the injury of sciatic nerve of model mice was detected by HE staining; the apoptosis of sciatic nerve was detected by TUNEL method; and the expression of neurofilament protein NF-L, apoptosis (cleaved Caspase-3, Caspase-3) and oxidative stress (Nrf2, HO-1) signal pathway proteins in sciatic nerve of model mice were detected by Western blot method.

RESULTS High-dose Juanbi Tongluo Oral Liquid shortened the latent period of heat pain response in model mice (P < 0.01); downregulated fasting blood glucose and glycated hemoglobin (P < 0.01), and upregulated fasting plasma insulin in model mice (P < 0.01); downregulated serum T-CHO, TG, and LDL-C levels (P < 0.01), upregulated HDL-C levels (P < 0.01); downregulated serum pro-inflammatory factors TNF-α, IL-1β and IL-6 levels (P < 0.05), upregulated the anti-inflammatory cytokine IL-10 level (P < 0.01); inhibited sciatic nerve structural damage and apoptosis (P < 0.05); downregulated the ratio of cleaved Caspase-3 to Caspase-3 in the apoptosis pathway (P < 0.01); upregulated the expression of neurofilament proteins NF-L and NF-H in sciatic nerve tissue (P < 0.05, P < 0.01); and upregulated the expression of antioxidant stress proteins Nrf2 and HO-1 (P < 0.01).

CONCLUSION Juanbi Tongluo Oral Liquid can improve sciatic neuronal apoptosis of Type 2 diabetic mice, which may be related to its effect on improving oxidative stress and inflammatory stress.