UTERINE SECRETIONS FROM DIFFERENT ENDOMETRIAL CLASSIFICATIONS AFFECT THE VIABILITY OF EARLY MURINE EMBRYOS CULTURED IN-VITRO

An interspecies (murine-equine) bioassay system was employed to invest igate the effect of equine endometrial secretions on embryonic surviva l. Uterine fluid was obtained from 15 diestrous mares by lavage with 1 50 ml of sterile Whitten's medium. Samples were grouped according to t heir Kenney score for endometrial type. Samples were sterilized and pr otein concentration was standardized to 4 mg/ml protein with BSA. Cont rols consisted of either 4 mg/ml BSA in Whitten's medium or 50% BSA-50 % heat-treated equine serum. One hundred 2-cell mouse embryos were cul tured in each sample and controls. Embryonic development was evaluated for 5 days and was expressed as the percent reaching the 4-cell, 8-ce ll, morula, blastocyst, expanded blastocyst, and hatched blastocyst st ages. Embryonic development in Type I mare uterine fluid did not diffe r from controls. Development to the 4 cell, 8 cell, morula, blastocyst and expanded blastocyst stages in the Type II mare media was less (p< .01) than the controls and other endometrial types. Development to all these stages was also lower than controls and Type I incubates in Typ e III mare media (p<.05), although development was higher in Type III compared with Type II. Leukocyte infiltration in the endometrium was a ssessed to determine the level of inflammation present in these mares. Basophil and neutrophil numbers were not different (p>.05) between en dometrial types. Lymphocyte numbers were significantly different (p<.0 5) between each endometrial type. The quantity of lymphocyte infiltrat ion was inversely proportional to the rate of in vitro embryo developm ent in Type I, Type II and Type III endometria.