Effect of IGF-I on spermatozoa membrane protein profile and correlation between seminal plasma IGF-I and antioxidant enzymes in buffalo semen

Abstract

The present study assessed the effect of insulin like growth factor–I (IGF-I) on spermatozoa membrane protein profile and relationship between IGF-I and antioxidant levels in buffalo (Bubalus bubalis) semen. Immediately after semen collection (n = 8), the seminal plasma and spermatozoa cells were separated by centrifugation (5000 g/10 min) and the seminal plasma IGF-I and antioxidant enzymes estimations were carried out. The spermatozoa were diluted (20 million cells/ml) in a tris-egg yolk extender, IGF-I (100 ng/ml of the semen) was added and incubated at 37ºC for 2 h. Membrane proteins were extracted with 0.1% Triton X 100 and protein profile was carried out by denaturing gel electrophoresis. No change in membrane protein profile was observed in spermatozoa treated with IGF-I as compared to control. The mean buffalo seminal plasma IGF-I, superoxide dismutase (SOD) and glutathione peroxidise (GPx) concentrations were 139.07±23.61 ng/ml (range: 51.45 to 267.43), 0.38±0.03 Unit/mg of protein (range: 0.16 to 0.74) and was 168.15±35.54 IU/mg of protein (range: 77 to 401), respectively while the total protein concentration (G %) was 2.89±0.20 (range: 0.88 to 5.27). IGF-I had no significant, correlation with SOD (r = –0.17) and GPx (r = –0.38). The correlation between SOD and GPx was significant and positive (r = 0.77). The present study revealed that IGF-I had no correlation with SOD and GPx levels and its addition did not influence spermatozoa membrane protein profile in a spermatozoa incubated for 2 h