Teratozoospermia with amorphous sperm head associate with abnormal chromatin condensation in a Chinese family.

ABSTRACT

Male infertility affects approximately 7% of the male population. In about 40% of affected patients, the etiology remains unknown. Here, we report the cases of two infertile brothers who have a uniquely prevalent sperm phenotype with completely amorphous sperm heads. To investigate the mechanisms of familial teratozoospermia with amorphous sperm heads, chromatin condensation was assessed by aniline blue staining, western blot, sperm chromatin structure assay and atomic force microscopy in both the two brothers and 40 control fertile donors. Our results showed an abnormal condensation of chromatin with amorphous headed sperm. We suggest that abnormal chromatin condensation which was induced by disturbances in the process of histone-protamine replacement may be a possible cause of familial teratozoospermia with amorphous head, and the elasticity of sperm nuclei could be a new index to assess sperm quality. Additionally, for the first time, the current study provided a new biomechanics strategy for evaluating pathological sperm contributes to our understanding of teratozoospermia.Abbreviations SCSA sperm chromatin structure assay; AFM atomic force microscopy; ICSI intracytoplasmic sperm injection; HDS high DNA stainability; DFI DNA fragmentation index; PBS phosphate-buffered saline; DTT dithiothreitol; FITC fluorescein isothiocyanate; DAPI 4',6-diamidino-2-pheneylindole; SSC standard saline citrate.