Testicular morphological and biochemical perturbations in experimental animals under antiretroviral therapy and the role of Naringenin, a bioactive flavonoid.

Abstract

Declining male fertility is one of the neglected concerns of people living with HIV/AIDS in spite of a dual outlook of a social and a health dilemma. This issue of infertility is particularly relevant as majority of affected individuals are in their reproductive years. This thesis examines the impacts of the Fixed Dose Combination (FDC) of Highly Active Antiretroviral Therapy (HAART) Tenofovir/ Emtricitabine and Efavirenz (TDF/FTC/EFV) on the male reproductive capacity. It also explores the protective potentials of a bioactive flavonoid, Naringenin in testicular perturbations. The study was motivated by two major research questions namely: (1) what are the impacts of the recently approved first line antiretroviral therapy for adults FDC, TDF/FTC/EFV on the testes? (2) What is the role of Naringenin in alleviating testicular perturbations induced by HAART? Previous studies point to the negative impacts of the older generation of FDC of HAART on the semen quality and histomorphometry of the testes following a long-term use. The study addresses both the long-term and short-term use of antiretroviral drugs as observed in pre-exposure prophylaxis (PrEP) and post exposure prophylaxis (PEP). The research assesses the impacts of the drugs on the reproductive capability as well. Findings from this study support the argument that the negative effects of the drugs were consequent upon both the short-term and long-term use. To illustrate this hypothesis, the study was conducted in two distinct phases. The first phase which lasted a total of 28 days considered the duration of PEP or PrEP. The second phase which lasted a total of ten weeks captured all the stages of spermatogenesis in rats. In this phase male Sprague Dawley rats were exposed to fertile females after the treatments. The study thus advances an understanding of the mechanism of HAART-induced testicular injury. A therapeutic dose of TDF/FTC/EFV adjusted for animal weight was aministered on a total of 48 animals randomly divided into 6 equal groups each with a different treatment as follows; Group A: Control (Distilled water); Group B: HAART (TDF/FTC/EFV), Group C: Naringenin, 40 mg/kg; Group D: Naringenin, 80 mg/kg; Group E: HAART + Naringenin, 40 mg/kg; Group F: HAART+ Naringenin, 80 mg/kg. At the end of each phase, harvested testes were subjected to histomorphometry and ultrastructural analysis. The caudal epididymis was assessed for semen parameters and sperm mitochondrial DNA (mtDNA) fragmentation. Biochemical parameters such as serum levels of reproductive hormones (Luteinizing hormone and Testosterone) and intratesticular antioxidant enzyme activities were assayed. Contrary to prior beliefs, this research reveals that the immediate effects following short-term use of HAART are far more deleterious. This finding is consequent upon the significant drop in the sperm count (p˂0.001) and sperms with normal morphology (p˂0.001) compared to (p˂0.01) in the long-term. Histomorphometric analysis also revealed a significantly shrunken seminiferous tubule following a short-term use. These outcomes were associated with an increase in the mtDNA fragmentation in group B when compared to control (p˂0.05). Naringenin reversed abnormalities in groups E and F, displaying better semen parameters in both count and motility. Serum levels of testosterone were altered in both phases. The overall effects of all these changes were observed in the pregnancy rate which reduced in group B when compared to all the other groups. This study established that HAART has deleterious effects on the testicular microanatomy and function. These effects may impact on steroidogenesis and ultimately spermatogenesis. It consequently impairs fertility while Naringenin promises to be a potential complimentary adjuvant especially in the short term therapies. Keywords: HAART, semen parameters, reproductive hormones, testicular ultrastructure, 3 beta hydroxysteroid dehydrogenase.