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[Effect of HFMC injection of various concentrations on patency of vas deferens and resumption of fertility in rats].

Great efforts have been made to develop non-occlusive or non-ever-lasting-occlusive contraception devices in vas deferens during the recent decade at home and abroad. In our previous studies both in vivo and in vitro, polymer HFMC was found to have a spermicidal effect. In this investigation in SD rats, the relationship between the concentration of HFMC injected into the vas deferens and the resumption of fertility was studied by means of continual observations on the existence of sperms in vaginal smears from the caged female and on pup-birth delaying, so as to determine occlusion of the vas lumen and the effect of HFMC on contraception in male. The histopathological changes in the vas deferens and caudal epididymis of the HFMC-injected male rats were also observed. The results indicated: (1) HFMC in concentration over 7.5% could show temporary contraception effect by its slow releasing of H+; (2) HFMC could induce definite contraception effect which lasted longer as the concentration of HFMC given increased; (3) HFMC had no effect on the descendents in number, mortality, sex ratio, body weight and appearance; (4) the bilateral internal reproductive structures were identified normal after resumption of fertility, but 20% HFMC induced vas deferens occlusion and spermatoceles; (5) moderate concentration of HFMC was considered favorable for reversible intra-vas deferens contraception.