Effect of Co-administration of Astragalus hamosus L. ethanolic Extract and Metformin on Reproductive Parameters in Diabetic Male Rats

Background and purpose: The seeds of Astragalus hamosus L. are prescribed for many therapeutic purposes in Traditional Persian Medicine. The present study aimed to investigate the combined effects of metformin and ethanolic extract of Astragalus hamosus L. (AH) on glucose and reproductive parameters in diabetic male rats. Materials and methods: Ethanolic extract of AH was prepared using maceration method. Diabetic male Wistar rats were orally treated with 500 mg/kg metformin (MET500), 150 mg/kg AH, (AH150), 300 mg/kg AH (AH300), and combination of metformin and AH (MET+AH150 and MET+AH300) for 28 consecutive days. Then, fasting blood glucose (FBG), plasma testosterone, sperm quality (count, motility, and viability), testis histopathology, and testicular lipid peroxidation (MDA) were evaluated. Results: Compared with the untreated diabetic group, AH treatment significantly improved testosterone level, sperm count, motility, and viability and decreased testicular MDA (all P<0.01) but it could not change glucose level (P>0.05). AH co-administration with metformin significantly potentiated the beneficial effects of metformin on testosterone (P<0.01) and testicular lipid peroxidation at both doses (P<0.001). While AH co-therapy with metformin at the maximum dose (300 mg/kg) synergistically improved metformin effects on testis morphology (all P<0.05), it could not show a positive combined effect on sperm parameters. Conclusion: AH has no antidiabetic effect and its co-therapy with metformin does not alter the hypoglycemic effect of metformin. However, this combination therapy has a synergistic effect on regulating lipid peroxidation, testosterone level, and testicular histological alterations in diabetic rats.