Effect of seminal plasma proteins on membrane cholesterol efflux of ram epididymal spermatozoa

This experiment was conducted to determine the effect of seminal plasma protein (SPP) on the membrane cholesterol efflux of ram epididymal spermatozoa. To obtain epididymal spermatozoa, testes of five healthy mature rams were collected from slaughterhouse in five times. Epididymal spermatozoa were split into three groups and it was added 0, 0.3 and 0.6 mg/ml SPP and control group (containing 0.6 mg/ml SPP without sperm) was included. Each group was split into three subgroups and incubated at 37 degrees C. Sperm motility, viability and functional membrane integrity were evaluated after 0, 2 and 4 h incubation. At 4h, a sample was centrifuged by 10,000 x g at 4 degrees C for 10 min and the concentration of cholesterol was determined in supernatant by gas chromatography. The main effect of seminal plasma protein showed that sperm motility was highest at 0 mg/ml SPP (66.33%; P < 0.05) and there was no difference between 0.3 (56.70%) and 0.6 mg/ml SPP (53.33%; P > 0.05). The highest and lowest functional membrane integrity were observed at 0 (84.00%) and 0.6 mg/ml SPP (77.13%), respectively (P < 0.05). Sperm viability was higher at 0 mg/ml SPP (87.27%) than 0.6 mg/ml SPP (84.47%; P < 0.05) and there was no difference between 0.3 (85.87%) and 0.6 mg/ml SPP (P > 0.05). The concentration of cholesterol was highest at 0.6 mg/ml SPP (3.95 mu g/100 x 10(6) sperm) and lowest at 0 mg/ml SPP (0.1 mg/100 x 10(6) sperm) and control (0.0 mg), respectively (P < 0.05). Therefore, seminal plasma proteins induced cholesterol efflux from ram epididymal spermatozoa. (C) 2015 Elsevier B.V. All rights reserved.