Effects of Orlistat on Testicular Redox Markers and Reproductive Parameters in High-Fat-Fed Male Rats

Abstract

Dietary fat intake can modify the nutritional, hormonal, and oxidative environment supporting male reproduction. Orlistat reduces fat absorption, but its effects on testicular function and sperm characteristics require evaluation alongside these metabolic changes. This study investigated testicular redox markers, serum testosterone, epididymal sperm characteristics, and testicular histology during
concurrent high-fat feeding and orlistat administration. Forty male rats were assigned to five groups receiving a standard diet, a high-fat diet, or a high-fat diet with oral orlistat at reported doses of 360, 480, or 600 mg/kg/day for 60 days. Compared with the untreated high-fat group, all orlistat groups showed lower testicular malondialdehyde and thiobarbituric acid-reactive substances, indicating lower measured lipid peroxidation markers. Testosterone decreased progressively across treatment doses, reaching 1.44 ng/mL at the highest dose, compared with 2.50 ng/mL in the high-fat control and 1.43 ng/mL in the standard-diet control. Mean sperm viability declined from 75.6% in the high-fat control to 62.8% at the highest dose, although this remained an exploratory observation. Motility showed no clear between-group difference. Histological appearances varied across doses, with apparently preserved spermatogenic architecture at the highest dose despite lower mean sperm viability. These findings suggest that biochemical, hormonal, and sperm responses to orlistat do not necessarily change in parallel. Altered nutrient availability and endocrine–redox interactions provide a plausible framework for interpreting this pattern. Measurements of energy substrates, sperm ATP, reproductive hormones,
and functional fertility are needed to determine the underlying pathways and clarify whether lower lipid peroxidation markers translate into improved reproductive function under comparable conditions.