The effects of a green rooibos extract on the reproductive function of obesity-induced insulin resistant or hypertensive male wistar rats
Year: 2019
Type: dissertation
Abstract: Diet-induced obesity (DIO) due to a high caloric diet (HCD) predisposes an individual to the development of diabetes and cardiovascular diseases, with high prevalence in young populations.Existing evidence supports the sentiment that insulin resistance and hypertension (HT) affect male reproduction.A greater understanding of the influence of insulin resistance and/or HT on male reproduction is required in order to prevent or treat male infertility.Due to the limitations of orthodox drugs, there is currently a strong movement towards and support for studies on phytomedicine.Rooibos (Aspalathus linearis) has been used in several studies and is known to have natural antioxidant effects and anti-obesogenic, antidiabetic, anti-hypertensive and anti-infertility activities.Currently, the company Afriplex (Pty) Ltd is producing an aspalathin-rich laboratory standardized extract prepared from green rooibos called Afriplex GRT TM (GRT).However, there is very little knowledge regarding the use of GRT in obesity-related insulin resistance and/or HT, and specifically, its effects on male reproductive health. AimThis study aimed to explore the effect of GRT on the reproductive function in obesity-induced insulin resistant and hypertensive male Wistar rats. MethodsA prospective randomized control and experimental animal study design was used.Two different diets were used to induce obesity-related insulin resistance with or without HT in male Wistar rats.Subsequently, the possible protective properties of GRT on the male reproductive system were evaluated.Animals (weighing 120 ±10 g, approximately 7 weeks old) were randomly assigned to seven groups with seven rats each.All rats had unrestricted access to their respective diets and water for 16 weeks.At baseline (week 0-10), we had three groups: 1) lean control (LC)animals that received standard rat chow; 2) obese (OB)animals that received a diet to induce obesity associated with insulin resistance; and 3) obese with hypertension (OBHT)animals were placed on a slightly modified DIO and additionally developed HT.From weeks 11 to 16, one LC, OB and OBHT group were each treated with GRT (prepared and supplied by Afriplex (Pty) Ltd) at 60 mg/kg/day as a dietary supplement in the form of jelly blocks.An additional group of OBHT animals was treated during the same period for 6 weeks with Captopril, an angiotensin-converting-enzyme (ACE) inhibitor (positive control for HT) at 60 mg/kg per day.Food and water intake were monitored on a daily basis.An oral glucose tolerance test was performed during the 10 th week after the onset of the respective diets and during the 16 th week, after which the Stellenbosch University https://scholar.sun.ac.za iv animals were sacrificed.Blood pressure measurements were taken once per week throughout the experimental period.After the 16-week period, animals were killed and blood, testis and epididymal tissue were harvested for further analysis.Body weight, intra-peritoneal fat, non-fasting glucose levels, IL-1β, IL-6, IL-12, IL-18 and TNFα, oxidative stress (OS) markers (superoxide dismutase and catalase activity, malondialdehyde), testosterone and estradiol, sperm concentration, viability, morphology, total motility, progressive motility and various velocity parameters were measured. Results and conclusionBoth diets successfully induced insulin resistance with or without hypertension and demonstrated detrimental effects on male reproductive function as evidenced by OS and hormone dysregulation.Treatment with GRT reversed OS and balanced the androgens.This study provided insight into the pharmacological effects of GRT in the treatment of pathophysiological changes that occur in DIO associated with insulin resistance or HT.These findings will hopefully inspire further research into the clinical setting related to the GRT and could possibly lead to the development of new drugs from this compound.
Author: Claudine Manirafasha
Language: English
Subfield: Reproductive Medicine
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W3003518407