Influence of genistein aglycone on some male reproductive functions in pubertal Holtzman rats

Background: Genistein, a phytoestrogen found in abundance in soya has been known to adversely influence male reproductive system. The effects of genistein on some male reproductive functions were investigated in pubertal laboratory rats. Methods: Male Holtzman rats, 70-75 days old and weighing 200-250g were used for the study. They were grouped into five groups of ten rats each. Group 1 (control) received distilled water. Groups 2, 3, 4, and 5 were administered orally with 0.5, 1, 2, 4 mg/ kg body weight of genistein respectively for a period of 60 days. Daily feed consumption and final body weight were recorded. Sperm count and motility were analysed along with the serum testosterone, estradiol and leptin levels. Acrosome reaction (AcR) was assessed using PSA-FITC with calcium and progesterone as stimulants. Male potency and fertility index were also calculated. Results: There was significant decrease in feed consumption in the 2 and 4 mg/kg genistein groups within the first 15 days of the experiment with a corresponding decrease in final body weights in 0.5, 2 and 4 mg/kg groups. A significant decrease was recorded in the right and the left absolute testicular weights in 0.5, 2 and 4 mg/kg groups while the right and left absolute epididymal weight and the prostate gland were significantly reduced in 2 and 4 mg/kg groups. The result showed a significant decrease and increase in serum testosterone level in 0.5 and 1 mg/kg groups respectively. Estradiol level was significantly reduced in all the genistein treated groups. Serum leptin was significantly increased in 1 mg/kg group. Sperm count was significantly reduced in 4 mg/kg group while sperm motility was reduced in the 2, and 4 mg/kg groups. Sperm track speed; lateral amplitude and elongation were significantly increased in all the genistein groups. Sperm path velocity was increased in all genistein groups except in the 4 mg/kg group. Progesterone stimulated AcR resulted in largely intact acrosome in all genistein group while calcium significantly increased percentage of reacted acrosome in 0.5 mg/kg group. Combined stimulation with progesterone and calcium increased AcR when compared with either of the stimulators alone. Potency and fertility index were significantly reduced in both 2 and 4 mg/kg groups while days of cohabitation before successful mating were increased in the 2 and 4 mg/kg groups. Ploidy analysis showed a significant increase and decrease in the population of elongating spermatid (HCI) and round spermatid (IC) in 2 and 4 mg/kg respectively. Pre-leptotene spermatocytes and primary spermatozoa population were significantly decreased in 4 mg/kg group. Conclusion: Oral administration of genistein to pubertal Holtzman male rats adversely influenced some important male reproductive functions