Effect of aqueous extract of Anchomanes difformis on testes and epididymis of streptozotocin-induced diabetic male Wistar rats

Abstract

Diabetes mellitus (DM) is a chronic metabolic disease characterized by hyperglycemia, and its prevalence continues to rise worldwide. Hyperglycemia is accompanied by oxidative stress, which consequently leads to the damage of macromolecules in the body. Due to oxidative stress, the male reproductive organs are compromised, which interferes with sperm production and storage, and leads to male infertility. Increase in the prevalence of DM is associated with the increase in the prevalence of male infertility. Synthetic drugs have been produced as treatment of DM complications. Most of these drugs cause side effects which include hypoglycemic in DM patients. Due to the side effects, cost of production and unaffordability of these synthetic DM drugs, scientists have found alternative and complementary medicine in plants / plant products. Oxidative stress is alleviated by antioxidants, both endogenous and exogenous. Some plants have been found to contain antioxidant compounds and this has led to the interest in using medicinal plants to increase antioxidant capacity where oxidative stress is increased in diabetic models. This has yielded findings that suggest the potential benefits of medicinal plants in ailments accompanying DM, including male infertility. Anchomanes difformis (A. difformis) is one of the plants found to contain antioxidant compounds and has been reported for its benefits in health. A. difformis has however, limited studies related to the treatment of male infertility. This study investigated the ameliorative effect of A. difformis extract on oxidative stress-induced testes and epididymis in a DM model, to find this extract’s potential benefits on the treatment of male infertility. Sixty-four (64) male Wistar rats weighing approximately 180±10g were randomly grouped into 7 groups namely, normal control (NC), control treated with 200 mg/kg dosage (C200), control treated with 400 mg/kg (C400), diabetic control (DC), diabetic treated with 200 mg/kg (D200), diabetic treated with 400 mg/kg (D400) and diabetic treated with glibenclamide (GLB), with 8 rats in each group of non-diabetic (normal) rats, and 10 rats per group of diabetic rats. Type 2 diabetes mellitus (T2DM) was induced after 14 days by 10% fructose administration and intraperitoneal injection with 40 mg/kg body weight dose of streptozotocin (STZ). Treatment with A. difformis aqueous extract commenced 5 days after the induction which lasted for 42 days. Both the testes and epididymis were weighed to assess weight relative to body weight and antioxidant and oxidative stress assays were performed on both organs to determine the effect of A. difformis aqueous extract. Oxidative stress was determined by measuring the level of malondialdehyde (MDA), a biomarker of lipid peroxidation. Catalase (CAT) and superoxide dismutase (SOD) activities, and reduced glutathione (GSH) concentration were measured to determine antioxidant status. Furthermore, antioxidant capacity of A. difformis against free radical such as 2, 2-diphenyl-1-picrylhydrazyl and metal chelating property were also investigated by performing ferric reducing antioxidant power (FRAP) and 2, 2-diphenyl-1-picrylhydrazyl (DPPH) assays. The relative testes weight was increased with DM induction while A. difformis extract showed no effect on the relative testes weight. However, relative epididymis weight was lower in the diabetic group, and increased with A. difformis extract treatment. MDA was higher in the diabetic control group compared to the normal control group. A. difformis extract lowered MDA levels in diabetic rats. Both CAT and SOD activities were reduced in the diabetic testes and restored back to normal with the administration of the extract. GSH level remained unchanged in the testes of all groups. All the antioxidants enzymes and GSH showed no significant difference in the epididymis with induced diabetes and treatment with the plant extract. Similarly, FRAP and DPPH showed no significant change in the epididymis. The testes also showed no change in DPPH. FRAP capacity was reduced in the testes of diabetic control compared to the control group, and the plant extract showed no effect in this reduction. T2DM model was established with observed symptoms such as elevated glucose levels and a decrease in body weight in diabetic control rats. Diabetes-mediated hyperglycemia caused oxidative stress in the testes, although it was not observed in the epididymis. A. difformis extract showed a protective effect against oxidative stress on the testes. With these in vivo experimental findings, A. difformis extract looks promising for the development of potential agent for the treatment of male infertility associated with DM. Thus, further studies on the isolation of the pure compounds and their mechanism of actions are worthy of investigation.