Effect of Bu-Zhong-Yi-Qi-Tang on deficiency of N-glycan/ nitric oxide and islet damage induced by streptozotocin in diabetic rats

AIM： To investigate the effect of Bu-Zhong-Yi-Qi-Tang （Decoction for Reinforcing Middle Jiao and Replenishing Qi） on deficiency of N-glycan/nitric oxide （NO） and islet damage induced by injecting two medium doses of streptozotocin （STZ）. METHODS： Diabetes was induced by intraperitoneal injection of STZ at 55 mg/kg on day 1 and day 8. Islet damage was evaluated using a scoring system. Nitrite, nitrate, α-mannosidase and amylase activities were measured by colorimetry. N-glycan patterns of amylase were determined with lectin [ConA, pisum sativum agglutinin （PSA）, peanut agglutinin （PNA）, and lens culinaris agglutinin （LCA）] affinity precipitation method. RESULTS： Severe islet necrosis and mild islet atrophy were observed in diabetic rats. The number and size of islets, the activities of α-mannosidase, amylase and nitrite were decreased, while the binding of PNA and LCA to amylase was increased. All of which were improved after treatment with Bu-Zhong-Yi-Qi-Tang. Islet damage was significantly correlated with nitrite, nitrate, α-mannosidase, amylase and the binding of LCA, PNA, and PSA to amylase.CONCLUSION： STZ-induced islet damage is related to N-glycan deficiency in proteins by blocking α-mannosidase activity and No deficiency, accumulation of unfolded proteins, and endoplasmic reticulum stress and activation of cellular signals, all of which are improved after treatment with Bu-Zhong-Yi- Qi-Tang.