Anti-diabetic effect of betulinic acid on streptozotocin-nicotinamide induced diabetic male mouse model

ABSTRACT Diabetes is a metabolic disease caused by abnormal insulin secretion or action. In the present study, the effects of betulinic acid (BA, a triterpene) are evaluated on glucose, α-amylase and plasma insulin levels, insulin resistance and the histopathology of pancreatic islets in streptozotocin-nicotinamide (STZ-NA) diabetic mice. Seventy adult male NMRI mice were randomly divided into seven groups: control, sham, diabetic, diabetic treated with BA (10, 20 and 40 mg/kg) and diabetic treated with metformin (200 mg/kg). Diabetes was induced in mice by intraperitoneal injection of streptozotocin 50 mg/kg after a dose of nicotinamide 120 mg/kg. Two weeks after treatment with BA, blood samples were collected for measuring glucose, α-amylase and insulin levels, and the pancreas was isolated for histopathology evaluation. Diabetes reduced the number and diameter of pancreatic islets, and increased α-amylase and insulin resistance. BA treatment reduced blood glucose, α-amylase and improved insulin sensitivity as well as pancreas histopathology. In addition, BA showed stronger effects on the pancreatic histology and insulin resistance compared to the metformin group

Effects of Betulinic Acid on the Male Reproductive System of a Streptozotocin-Nicotinamide-Induced Diabetic Mouse Model

PURPOSE: The present study was conducted to evaluate the favorable or harmful effects of betulinic acid (BA) on a diabetic reproductive system. MATERIALS AND METHODS: In this experimental study, 60 male Naval Medical Research Institute mice (20∼25 g) were randomly divided into 6 groups: control, diabetes, diabetes+BA (10, 20, and 40 mg/kg), and diabetes+ metformin (200 mg/kg). A diabetic model was induced by a single dose of streptozotocin (STZ) (65 mg/kg) injection intraperitoneally 15 minutes after an intraperitoneal administration of nicotinamide (NA) (120 mg/kg). BA and metformin were gavaged for 2 weeks after confirmed diabetes induction in the treatment groups. One day after the last treatment, plasma luteinizing hormone (LH), follicle-stimulating hormone (FSH), and testosterone levels were evaluated. The cauda epididymis and testis were removed to analyze the sperm count and testis histopathology. RESULTS: LH levels increased in diabetic (p<0.001) and diabetic BA-treated mice (p=0.009). Plasma levels of testosterone (p< 0.001) and sperm count (p=0.04) decreased in these groups when compared to the control group. Furthermore, administration of 10 mg/kg (p=0.001), 20 mg/kg (p=0.004), or 40 mg/kg (p<0.001) of BA led to a greater reduction in plasma testosterone levels compared to the diabetes group. Seminiferous tubule vacuole numbers increased in diabetic and diabetic BA-treated mice, but testis morphology and FSH level assessment revealed no significant differences between the groups. CONCLUSIONS: STZ-NA can induce diabetic alterations in the male reproductive system and the administration of BA in diabetic treated mice resulted in a worse outcome.