Abstract: Objective: To explore the protective effect of flaxseed oil in comparison with fish oil on streptozotocin (STZ)-induced diabetic nephropathy (DN) in rats. Methods: An animal model of DN was established by a single intraperitoneal injection of STZ in rats. The experimental rats were divided into one negative control group, one model group, three flaxseed oil groups (0.3, 0.6, and 0.9 mL/100 g mb), and one fish oil group (0.6 mL/100 g mb). Glucose metabolism indexes including fasting blood glucose, glucose tolerance and glycosylated serum protein (GSP), renal function indexes including urine volume, urine protein, creatinine and urea nitrogen, as well as cytokines and oxidative stress status were determined in all the animals. Histological changes of pancreas and kidney tissues were observed. Results: Compared with the model group, flaxseed oil and fish oil could significantly reduce fasting blood glucose level, improve glucose tolerance and GSP, decrease urine volume and urine protein, improve renal function and reduce inflammatory reactions. Both of them could enhance antioxidant capacity and significantly increase the expression of glucose transporter-4, insulin, pyruvate kinase and hexokinase in liver (P < 0.05 or P < 0.01). Moreover, histopathological observation showed that flaxseed oil could alleviate pancreas and kidney injury in DN rats. Conclusion: Both flaxseed oil and fish oil have a protective effect on STZ-induced DN. The underlying mechanism may be related to the regulation of glucose metabolism, and the anti-inflammatory and antioxidant capacity. Comparatively, fish oil is more effective in regulating carbohydrate metabolism, while flaxseed oil has a better protective effect on the kidney.

Key words: flaxseed oil, streptozotocin, diabetic nephropathy, protective effect