Intravasal contraception with styrene maleic anhydride and its noninvasive reversal in langur monkeys (Presbytis entellus entellus).

PMID 9773267


In male langurs with azoospermia induced by vas occlusion with styrene maleic anhydride (SMA), the exploratory feasibility of azoospermia reversal by a new noninvasive reversal procedure has been assessed. Palpation, percutaneous electrical stimulation of the vas deferens, forced vibratory movement, suprapubic percussion, and per rectal digital massage of the vas deferens are the components of the multimodal noninvasive reversal procedure. The exploratory investigation reveals that a single application of the procedure leads to reversal of azoospermia. Normospermia with normal motility and viability appears after third ejaculation onwards after reversal manipulations. Ultrastructure of the spermatozoa, using scanning and transmission electron microscopy, revealed that the spermatozoa attained normalcy and sperm functional tests (i.e., hypo-osmotic swelling test, slide test for acrosome intactness, and test for sperm mitochondrial activity index) further confirmed the normalcy of the spermatozoa toward their fertilizing ability. Semen biochemistry appeared normal throughout the course of investigation. The morphology of the vas deferens, which showed exfoliation of the epithelium, was in the process of regaining normalcy after 90 days of reversal manipulations. The results suggest that noninvasive reversal technique offers the possibility of the functional azoospermia reversal within a short period of time.

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Poly(styrene-alt-maleic acid) sodium salt solution, 13 wt. % in H2O