Effects of myoinositol on sperm mitochondrial function in-vitro

BACKGROUND AND OBJECTIVES: Inositol is a component of the vitamin B complex. Myo-inositol (MYO) is the most biologically important form in nature. It is involved in several systemic processes and in mechanisms of signal transduction in the plasma membrane as precursor of second messengers. On the male reproductive function, MYO appears to regulate seminal plasma osmolarity and volume; the expression of proteins essential for embryogenetic development and sperm chemiotaxis; and sperm motility, capacitation, and acrosome reaction. Recently, a seminal antioxidant action has also been suggested. AIM OF THE STUDY: To evaluate the effects of MYO on sperm mitochondrial function and apoptosis. MATERIALS AND METHODS: Spermatozoa isolated from 5 normozoospermic men and from 7 patients with oligo-astheno-teratozoospermia (OAT) were incubated in-vitro with 2 mg/ml of MYO or placebo (control) for 2 hours. After this incubation period, the following sperm parameters were evaluated by flow cytometry: mitochondrial membrane potential (MMP) by JC-1 staining; phosphatidylserine (PS) externalization by annexin V and propidium iodide double staining; and chromatin compactness following propidium iodide staining. RESULTS: MYO did not affect the mitochondrial function of spermatozoa isolated from normozoospermic men, whereas it increased significantly the number of spermatozoa with high MMP and decreased significantly the number of those with low MMP in OAT patients. No effect of MYO was observed on PS externalization and chromatin compactness in both normozoospermic men and OAT patients. CONCLUSION: The data suggest that MYO is able to ameliorate mitochondrial function in OAT patients. We conclude that this compound may be useful for the treatment of male infertility.