[Treatment of type 2 diabetes mellitus with the stem and leaf of blacktartary buckwheat and its effects on the pancreas and spleen].

To investigate the therapeutic effects of the black buckwheat leaf (BBL) in type 2 diabetes mellitus mice and its effects on pancreas and spleen.

Forty male C57 / B16 mice (SPF) were randomly divided into normal control (NC) group (n=10) and the experimental group (n=30), the experimental group were fed with high sugar and high fat, combined with intraperitoneal injection of streptozotocin in small dose to establish the model of type 2 diabetes mellitus (T2DM). Those thirty model mice were randomly divided into 3 groups (n=10), diabetes mellitus group (DM), low dose of BBL (DM+L) treated group, high dose of BBL (DM+H) treated group. The mice in the NC group and the DM group were given normal saline per day, and the DM+L group and DM+H group were treated with black tartary buckwheat at the doses of 0.21g/kg·d^-1 and 0.42g/kg·d^-1 respectively. After 14 days. All mice were executed by cervical dislocation, then blood samples were collected, pancreas and spleen were removed for subsequent experiments. The serum levels of fasting blood glucose (FBG), triglyceride (TG), total cholesterol (TCH) and insulin were detected. TNF-α protein in spleen tissue was detected by ELISA kit. The morphology of pancreas tissue was observed by HE staining, and the spleen coefficient was calculated. The expression levels of insulin receptor substrate-1(IRS-1) mRNA and IRS-1 protein in pancreatic tissue were detected.

Compared with the control group, the serum levels of FBG, TC and TCH in the model group were increased significantly, while the serum level of insulin was decreased significantly (P＜0.05), the expression of TNF-α protein in spleen tissues was obviously raised, the expressions of IRS-1 mRNA and IRS-1 protein in pancreatic tissue in model group were decreased significantly (P＜0.05). Compared with the model group, the serum levels of FBG, TC and TCH were decreased significantly in the BBL treated groups. The serum insulin level, spleen coefficient, TNF-α protein expression level in spleen tissue, IRS-1 mRNA expression and IRS-1 protein expression levels in pancreatic tissue in BBL treated group were increased significantly (P＜ 0.05). High-dose black tartary buckwheat leaves (0.42g/kg·d^-1) exerted a more significant effect.

Stem and leaf of black bitter buckwheat has significant therapeutic effects on reducing blood sugar and blood fat in type 2 diabetic mice, and has certain protective effects on pancreas and spleen of diabetic mice.