Ultrastructural alterations in sperm heads under influence of several implementors to ram semen

Abstract

In our study we tested effects of chosen implementors on the acrosomal status of ram sperm heads on the basis of ultrastructure of sperm membranes and acrosome. Fresh sperm, diluted in a commercial diluent – Biladyl, was divided into five groups according to individual implementor: IGF-I, EGF, glutathione, caffeine and control (no additions). Individual sperm heads were classified as belonging to one of four categories according to the state of sperm membranes and acrosome: grade I – sperm with intact plasma membrane of the head and intact acrosome; grade II – sperm with waved or cracked plasma membrane; grade III – sperm with swollen or damaged acrosome; grade IV – sperm with pseudoacrosomal reaction formed by exocytotic vesicles and accompanied with a loss of acrosomal content. Our results show that the occurrence of sperm classified to the grade I was mostly increased when IGF-I or EGF were added to sperm samples. Oppositely, caffeine did not affect frequency of the grade I sperm, but increased the occurrence of grade III and IV sperm, i.e. induced pseudoacrosomal reaction. Glutathione did not influence the frequency of the grade I and II sperm but decreased the grade III sperm occurrence. In conclusion, IGF-I, EGF and glutathione were able to maintain the sperm membrane stability, which is important in increasing sperm fertilizing potential. Caffeine, although increased sperm motility, but caused damages in sperm head membranes and induced pseudoacrosomal reaction. Our results suggest that the categorization of sperm head into four morphological grades may serve to the evaluation of the membrane status of ram sperm.