OBJECTIVETo explore the influences of di-(2-ethylhexyl)phthalate (DEHP) and its principle metabolite mono(2-ethylhexyl)phthalate (MEHP) on spermatogenic cell apoptosis in young male Wistar rats.

METHODSNinety-eight 2-week-old male Wistar rats were randomly divided into 14 equal groups to receive daily intragastric administration of 0.2 ml/kg normal saline for 3 weeks (normal control), 100 mg/kg cyclophosphamide (CTX) for 1 week (positive control), 100, 200, and 300 mg/kg DEHP or MEHP for 1 week, or 100 mg/kg DEHP or MEHP for 1, 2, and 3 weeks. After the treatments, the pathological changes of the testicular tissues were examined, spermatogenic cell apoptosis was detected, and serum sex hormones levels were measured using TUNEL assay or radioimmunoassays.

RESULTSCTX, DEHP, and MEHP all caused shrinkage, development retardation and quantitative reduction of spermatogenic cells with and mitochondrial swelling vacuolar changes. The damage of spermatogenic cells increased significantly with the increment of DEHP and MEHP doses and exposure time. Both DEHP and MEHP treatments resulted in significantly increased cell apoptosis index (AI) in close correlation with the exposure doses and duration (P<0.01). DEHP and MEHP treatments also significantly increased serum levels of follicle stimulating hormone and luteinizing hormone and decreased testosterone levels in a dose- and time-dependent manner (P<0.05).

CONCLUSIONDEHP and MEHP can induce obvious apoptosis of spermatogenic cells in young male rats with a dose- and time-dependent effect.