The effects of the wild african potato (hypoxis hemerocallidea) supplementation on streptozotocin-induced diabetic wistar rats reproductive function

Abstract

Diabetes mellitus (DM) has been reported to be one of the greatest global public health threats. Statistics of the fertility status of modern society has linked increased DM to a decrease in fertility rates. Hyperglycaemia is characteristic of DM that results in a disturbance of proteins, lipids and carbohydrate metabolism leading to an increase production of reactive oxygen species (ROS). In the case where ROS overwhelms antioxidant mechanisms, the body goes into state of oxidative stress (OS). OS plays a vital role in the progression of DM which leads to dysfunction and damage of various organs including that of the reproductive system. Os has shown to cause damage to the sperm membraneby oxidation of polyunsaturated fatty acids (PUFA’s) as the sperm membrane are rich in PUFA’s. This damage contributes to reduced sperm motility, concentration, morphological abnormalities and the sperms ability to fuse with the ZP of the oocyte. DM has been observed to cause testicular degeneration by interrupting sertoli cell production and maintenance thus resulting in a disturbance of the normal functioning of the reproductive system. Experimental studies have targeted more natural sources for treating DM and its complications of the reproductive system. Plants and natural dietary substances have shown to have high antioxidant contents that combat DM induced oxidative stress. This study explored the effect the Hypoxis hemerocallidea (H. hemerocallidea) supplementation on testicular and epididymal tissue, sperm motility and reproductive hormones in male wistar rats. The experiment were conducted for 6 weeks and the rats (230-260 grams) were randomly divided into 5 groups (n=12 per group). Diabetes was induced in 3 of the 5 groups. The first group was the normal control group (A), second the diabetic control group (B), third was the diabetic group treated with 800mg/kg H. hemerocallidea (group C), fourth the diabetic group treated with 200mg/kg H. hemerocallidea (group D) and fifth the non-diabetic group supplemented with 800mg/kg H. hemerocallidea (group E). Blood glucose showed a significant increase in the diabetic group when compared to the normal control and treated groups. H. hemerocallidea showed improvement in sperm motility and sperm morphology more at 800mg/kg when compared to diabetic group and diabetic group treated with 200mg/kg. Body, testicular and epipidymal weights of diabetic control were significantly lower when compared to the other groups. Testicular and epididymal Malondialdehyde levels were decreased in normal control, diabetic groups treated with different doses of H. hemerocallidea and the non-diabetic group supplemented with H. hemerocallideaon comparing with the diabetic control group. Antioxidants such as Superoxide dismutase, Catalase and total Glutathione activity was observed to be dosage dependent in certin groups but most showed a significant increase when compared to the diabetic control group. The total antioxidant capacity was measured using Oxygen radical absorbance capacity (ORAC) and Ferric ion reducing antioxidant power (FRAP); increase was observed when normal control group and treated groups were compared to the diabetic group. Testosterone and estradiol levels were also increased when the normal control group and treated groups were compared to the diabetic control group. Based on our findings it can be concluded that H. hemerocallidea supplementation can potentially be used to counteract deleterious effects of DM on the male reproductive system.