Improvement in buffalo (Bubalus bubalis) spermatozoa functional parameters and fertility in vitro: Effect of insulin-like growth factor-I

Abstract 

The aim of the current study was to assess the effect of insulin-like growth factor-I (IGF-I; 100 ng/mL) on buffalo (Bubalus Bubalis) sperm functional parameters related to in vitro fertilization. The acrosin activity (the mean diameter of halo formation in micrometers) was significantly higher in the IGF-I group (14.17 ± 1.51) compared with that in the control group (9.50±0.36) at 2h incubation. The mitochondrial membrane potential (per cent) was significantly higher in the IGF-I group compared with that in the control group at 30min (33.27±2.62 vs. 26.71±1.02), 60min (24.24±3.45 vs. 18.77±2.09), and 90min (22.86±3.02 vs. 16.92±1.24) incubation. The percentage of spermatozoa positive for sperm nuclear chromatin decondensation (NCD) differed significantly between the groups at 90 and 120min incubation. The comet length was significantly lower in the IGF-I group compared with that in the control group at 2h incubation. The percentage of fragmented DNA in the tail did not differ significantly between the groups at 2h incubation. The percentage of acrosomal-reacted spermatozoa did not differ significantly between the IGF-I and the control groups at 4h (41.12±6.44 vs. 43.53±5.05) incubation. The cleavage rate (per cent) was significantly higher in the IGF-I–treated group (56.73±3.70) compared with that in the control group (44.85±2.15). The current study suggests that the addition of IGF-I prevents deterioration of sperm functional parameters and fertility.

Keywords: IGF-I, Acrosin proteolytic activity, Acrosomal reaction, Mitochondrial membrane potential, Sperm-zona binding, Cleavage rate