Protective Effects of the Aqueous Extract of Tribulus cistoides (Zygophyllaceae) Against Nicotine-Induced Fertility Impairment in Male Wistar Rats

Infertility affects a substantial proportion of couples worldwide and is defined as the failure to achieve pregnancy after 1 year of regular, unprotected sexual intercourse. Growing interest has been directed toward ethnobotanical approaches for the management of male infertility. This study evaluated the therapeutic potential of the aqueous extract of Tribulus cistoides against nicotine-induced infertility in male Wistar rats. Thirty adult male rats were randomly allocated into six groups (n = 5). Group 1 received distilled water (5 mL/kg), Group 2 received nicotine alone (1 mg/kg), and Group 3 received nicotine plus testosterone enanthate (5 mg/kg), while Groups 4–6 were administered nicotine in combination with T. cistoides aqueous extract at doses of 50, 100, and 150 mg/kg, respectively, for a period of 60 days. Evaluated parameters included body and reproductive organ weights, testicular oxidative stress markers, seminal vesicle fructose, total testicular protein, sperm density and motility, serum testosterone, follicle-stimulating hormone (FSH), luteinizing hormone (LH), and testicular histoarchitecture. Nicotine administration resulted in a significant reduction in sperm density (15.00 ± 1.05 × 10⁶/g vs. 43.05 ± 3.06 × 10⁶/g), sperm motility (35.73% ± 0.72% vs. 56.44% ± 2.17%), and serum testosterone levels (0.124 ± 0.002 ng/mL vs. 0.521 ± 0.048 ng/mL) compared with the normal control group. Conversely, treatment with T. cistoides extract at 150 mg/kg significantly improved sperm density (50.15 ± 1.46 × 10⁶/g), motility (71.16% ± 4.15%), and testosterone levels (0.411 ± 0.016 ng/mL). In contrast, testosterone enanthate did not produce significant improvements in the fertility parameters assessed when compared with the nicotine-treated group. The extract also enhanced testicular antioxidant status, reproductive hormone profiles, seminal fructose levels, testicular protein content, and reproductive organ weights, likely due to its androgenic and antioxidant properties. Histological examination further revealed increased sperm density in the extract-treated groups like in the normal control group. In conclusion, the aqueous extract of T. cistoides exhibited notable protective and restorative effects against nicotine-induced male infertility, highlighting its potential as a natural therapeutic agent for improving male reproductive function.