Objective: To explore the ultrastructure and function of mitochondria in idiopathic asthenospermia and the role thereof in the sperm activity.
Methods: Samples of sperm were collected from 151 idiopathic asthenospermia patients, 25% of whose sperms were classified as lower than grade A, were subdivided into 3 groups: Group A with the proportion of grade A sperms between 15% and 25%, Group B, with the proportion of grade A sperm between 15% and 5%, and Group C with the proportion of grade A sperm < 5%. Transmission electron microscopy was used to observe the ultrastructure of the mitochondria in the sperms. Samples of sperm were collected from 53 normal patients as control group. The levels of succinate dehydrogenase (SDH) and mitochondrial membrane potential (MMP) were detected.
Results: The expression rates of SDH and MMP were decreased according to the sequence of the control group, group A, Group B, and Group C with significant between any two groups (all P < 0.01). Various mitochondrial pathological changes (MPCs) emerged in Groups A, B and C, however with different frequencies of occurrence for specific MPC in specific group (chi2 = 60.85, P < 0.01). The amount of abnormal mitochondria increased significantly according to the sequence of the control group, Groups A, B and C (chi2 = 479.72, b = 0.86, P < 0.01). The severity degree of MPC increased along with the decrease of sperm viability (chi2 = 435.89, b = 0.80, P < 0.01).
Conclusion: Various MPCs exist in idiopathic asthenospermia. There is a close association between the sperm viability and mitochondrial ultrastructure and mitochondrial function.