Antifertility Effects of Neem (Azadirachta indica) Oil in Male Rats by Single Intra‐Vas Administration: An Alternate Approach to Vasectomy

Abstract

ABSTRACT: An alternate approach to vasectomy for long‐term male contraception following a single intra‐vas application of a traditional plant (Azadirachta indica) product having immunomodulatory properties is described. Male Wistar rats of proven fertility were given a single dose (50 μl) of neem oil in the lumen of the vas deferens on each side; control animals received the same volume of peanut oil. Animals were put on continuous mating 4 weeks after the treatment, with females of proven fertility. While the control animals impregnated the female partners, all males treated with neem oil remained infertile throughout the 8 months of observation period. Epididymal and vas histology were normal without any inflammatory changes or obstruction. The intra‐vas administration of neem oil resulted in a block of spermatogenesis without affecting testosterone production; the seminiferous tubules, although reduced in diameter, appeared normal and contained mostly early spermatogenic cells. No anti‐sperm antibody could be detected in the serum. Unilateral administration of neem oil in the vas resulted in a significant reduction of testicular size and spermatogenic block only on the side of application; the draining lymph node cells of the treated side also showed enhanced proliferative response to in vitro mitogen challenge. These results indicate that the testicular effects following intra‐vas application of neem oil may possibly be mediated by a local immune mechanism. 1993 American Society of Andrology