Human Sperm Anatomy: Different Expression and Localization of Phosphatidylinositol 3-Kinase in Normal and Varicocele Human Spermatozoa

Recent reports support the possible role of PI3K in sperm capacitation and acrosome reaction, although studies regarding PI3K identity in human sperm, under certain disease states such as varicocele, are still lacking. The authors, therefore, examined the expression profile and ultrastructural localization of PI3K in human semen samples, comparing healthy donors and patients with varicocele. The results obtained performing western blotting assay showed decreased PI3K expression in varicocele with respect to the "healthy" sperm. Immunogold labeling revealed human sperm cellular compartments containing PI3K, evidencing it in the head at both the membrane and nucleus and the entire tail, from the middle to the end piece of normal sperm. In varicocele PI3K label was confined to the head, with a strong reduction of specific reaction in the neck, middle piece, and tail. In conclusion, the data suggest that PI3K may play a role in the maintenance of male factor infertility associated with varicocele, and it may be further exploited as an additional molecular marker for the diagnosis of male infertility disorders.