A modified method for the differential staining of spermatozoa using alcoholic acidic silver nitrate.

Differential silver staining patterns have been demonstrated in mammalian spermatozoa, using an aqueous silver nitrate reagent. In the present study, mouse, rabbit, and human spermatozoa were stained using a modification of the earlier method. In the modified method, an alcoholic acidic silver nitrate stain, with subsequent differentiation in alcoholic ammonia, was used. This method enhanced the intensity of staining of the head, mid-piece, and tail. In particular, marked differentiation of the acrosomal, subacrosomal, and postacrosomal regions was obtained, which facilitated determination of acrosomal integrity. Moreover, background interference was reduced, yielding better clarity of the stained smears. The staining was carried out in the cold. This modified technique offers an advantage in the assessment of sperm morphological anomalies and membrane and acrosomal integrity, and is a simple, reliable, and useful method for the evaluation of sperm function.