Browsing by Author "Plessis, Stefan S. Du"

Now showing 1 - 2 of 2

The efect of streptozotocin induced diabetes on sperm function: a closer look at AGEs, RAGEs, MAPKs and activation of the apoptotic pathway
(2020) Plessis, Stefan S. Du
Abstract: This study was designed to (1) investigate the possible mechanisms through which diabetes-induced advanced glycation end products (AGEs) and receptor for AGEs (RAGE) activation can afect male reproductive function; and (2) corroborate the interaction of previously established independent pathways. Male albino Wistar rats (14-weeks old) weighing 250–300 g received either a single intraperitoneal injection of streptozotocin (30 mg/kg or 60 mg/kg), represented as STZ30 or STZ60 respectively, or citrate bufer (control). Diabetes mellitus (DM) was confrmed if plasma glucose levels were ≥14 mmol/L after 1 week. Animals were sacrifced after 8 weeks of treatment by an overdose of sodium pentobarbital (160 mg/kg body weight). The testes and epididymides were harvested. The testes were used for biochemical and Western blot analysis, while sperm was retrieved from the epididymis and analysed with computer-aided sperm analysis. The blood glucose levels of STZ60 animals were above the cut-of point and hence these animals were regarded as diabetic. Diabetic animals presented with a non-signifcant increase in AGE and RAGE expression. Diabetic animals showed a signifcant increase in the expression of cleaved caspase 3 compared to control (p<0.001), and these animals also presented with an increase in the expression of JNK (p<0.05), PARP (p=0.059) and p38 MAPK (p=0.1). Diabetic animals also displayed decreased catalase activity accompanied by a non-signifcant increase in malondialdehyde levels. Additionally, there was a signifcant decrease in the percentage of progressively motile spermatozoa (p<0.05) in diabetic animals. This study has shed some light on the interplay between DM, AGE, RAGE and mitogen-activated protein kinase signalling in the testes of diabetic rats, which can result in altered sperm function and contribute to male infertility. However, more studies are needed to better understand this complicated process.
The effects of Lepidium meyenii on MSG-induced subfertility in male Wistar rats: Targeting oxidative stress, pro-inflammatory cytokines, steroidogenic enzymes, and reproductive hormones regulation
(Elsevier BV, 2025-01) Omolaoye, Temidayo S.; Rawat, Surendra Singh; Plessis, Stefan S. Du
Objective and rationale: Although monosodium glutamate (MSG), commonly used to enrich food flavour, is generally considered safe for consumption, evidence has shown its adverse effects on physiological functions, including male reproduction, when consumed excessively. Lepidium meyenii (Maca), on the other hand, a plant belonging to the Brassicaceae family, has been shown to have diverse health benefits. The current study investigated pathways through which MSG could induce subfertility, and whether treatment with Maca root extract would proffer amelioration via those routes. Methods: Eighteen male Wistar rats were randomly divided into three groups. Animals were orally (oral gavage) administered MSG (900 mg/kg/day for 45days), MSG and Maca (900 mg/kg/day of MSG and 500 mg/kg/day of black Lepidium meyenii root extract), or water only (control group), for a total period of 80 days. MSG was administered for the first 45 days, followed by Maca or water for the subsequent 35 days. Spermatozoa were collected from the caudal epididymis for sperm assessments. The testis and prostate were used for biochemical assays and immunofluorescent localization of biomarkers of interest. Results: MSG administration significantly reduced total and progressive sperm motility (p < 0.05), decreased total antioxidant capacity (TAC) (p < 0.001), increased mRNA expression of TNF-α, IL-6, IL-1β in the testis and prostate (p < 0.05), protein expression of GP130 in the testis, reduced serum testosterone, and altered expression of steroidogenic markers. These adverse effects were mildly ameliorated upon treatment with Maca. Conclusion: Findings highlights how MSG could cause male reproductive dysfunction via reduction of TAC, increase in pro-inflammatory cytokines, alter reproductive hormones and reduced protein expression of steroidogenic markers. Treatment with Maca significantly improved sperm motility, possibly by enhancing TAC levels and reducing proinflammatory cytokines. However, this hypothesis needs further investigation.