The effects of green tea (Camellia sinensis) extract on mouse semen quality after scrotal heat stress

The objective of this study was to investigate whether or not the adverse effects of heat on sperm quality could be prevented by green tea extract (GTE) administration. Ninety adult male mice were randomly divided to two groups. The scrotum of each animal in the first group was immersed once for 20 min in a water bath maintained at 42 oC (heat group, H) and the second group (control group, C) was maintained at 23oC. Heat-treated and control groups were allocated randomly into three subgroups. The first subgroup from heat-treated mice was administered sterile saline (heat saline, HS) and the two other subgroups were administered orally with two different doses of GTE including 500 and 750 mg kg-1 (HG500 and HG750) for 49 consecutive days. Likewise, the first subgroup from control mice was administered sterile saline (control saline, CS) and the two other subgroups were administered orally with 500 and 750 mg kg-1 of GTE (CG500 and CG750), respectively. Heat stress significantly reduced (P < 0.05) sperm concentration, total sperm motility, progressive sperm motility and hypo-osmotic swelling-water test positive spermatozoa at the first 14 days after the heat treatment. However, a partial recovery was observed at the day 42, which was still significantly lower than that of the CS group. Administration of GTE in two doses (HG500 and HG750 treatment groups) following heat treatment could significantly recover adverse effects of heat on above-mentioned parameters during the first 28 days. The present study demonstrates that the adverse effects of hyperthermia on semen parameters might be recovered following administration of green tea extract in a short period of time.