Factors that influence fertility after vasovasostomy in rats.

OBJECTIVE

To determine if fertility after vasovasostomy of immunologically responsive Lewis rats differs from that of the less responsive Sprague-Dawley strain and to relate fertility to antisperm antibodies, fluid flow in the vas deferens, and testicular structure.

DESIGN

Male rats received: (1) bilateral vasectomies; (2) vasectomies followed 3 months later by vasovasostomy; or (3) sham operations.

SETTING

Research laboratory.

MAIN OUTCOME MEASURES

Fertility was assessed by caging males with three females for 2 weeks and subsequently counting implantation sites. Antisperm antibodies were measured with an enzyme-linked immunosorbent assay, fluid flow through vas deferens segments was tested in vitro, and testicular structure was studied microscopically.

RESULTS

Nearly all vasovasostomized Lewis rats were infertile (33 of 34), whereas 62% (18 of 29) Sprague-Dawley rats were fertile after vasovasostomy (P less than 0.001). In fertile Sprague-Dawley males, significant correlations existed between: (1) implantation sites or females impregnated; and (2) antisperm antibodies early after vasectomy, vas flow, and testicular morphology.

CONCLUSIONS

Genetic differences affect fertility after vasovasostomy. Fertility after vasovasostomy is also influenced in a multifactorial manner by the immune response, mechanical elements, and structural changes in the reproductive tract.