361 OVIDUCT CILIARY CURRENTS IN BOVINE AND BUFFALO AT DAY 1 AFTER OVULATION

Abstract

Buffalo present a low embryo recovery rate after superovulation, due to failure of oocyte entry into the oviduct. The aim of this study was to evaluate the effect of the estradiol-17² on oviduct ciliary currents in bovine and buffalo at Day 1 after ovulation. Six Nelore cows and six Murrah buffalo cows were synchronized with an intravaginal progesterone device (DIB^®; Syntex, Argentina) plus 2 mg of estradiol benzoate intramuscular (i.m.) on Day 0 (D0). After eight days (D8) the device was removed and the animals received prostaglandin F2± analogue (0.15 mg i.m.; Prolise^®; Tecnopec, Sao Paulo, Brazil) plus 400 IU of eCG (i.m.; Novormon^®; Syntex). On D9, ovulation was induced with GnRH (25 ¼g i.m.; Gestran Plus^®; Tecnopec). After 48 h the animals were slaughtered and the oviducts were removed and rinsed in a solution of Dulbeccos's phosphate-buffered saline with 1% gentamicin (DPBS + gentamicin). The oviduct was lavaged with Hank's balanced salt solution supplemented with 25 mM HEPES (HBSS), and the mesosalpinx and fimbria were removed. The oviduct was then carefully incised along its entire length. After the luminal surface was exposed, the oviduct was secured with the luminal surface exposed in a 150 × 20-mm dish containing a layer of paraffin. The oviduct was then completely submerged in 100 mL HBSS (Group 1 - G1, n = 5 bovine; G2, n = 7 buffalo) or 100 mL HBSS with 10 ng/mL estradiol-17² (G3, n = 6 bovine; G4, n = 4 buffalo; factorial 2 × 2) that had been prewarmed to 38.5°C. The dish containing the oviduct was incubated for 30 min at 38.5°C to allow equilibration of temperature and culture medium. After equilibration, the oviduct in the culture dish was placed on a stereomicroscope (SMZ-1T) and the luminal epithelium was observed (×30). To assess ciliary beat, 450 black microspheres (10 ¼m; Polybead^®; Polysciences, Inc., Warrington, PA, USA) were applied to the luminal surface of the oviduct. The microspheres were applied dropwise (10 ¼L) to one portion of the infundibulum and the area of application was immediately observed to determine the direction of microsphere motion over approximately 1 min. The direction of motion was graduated in scale (0 = none, 1 = uterine, 2 = ovarian-uterine, and 3 = ovarian). Two-way analyses of variance was used to compare the effects of species (bovine × buffalo) and treatments (without estradiol × with estradiol) and the species-by-treatment interaction. The data were analyzed by General Linear Models procedure of SAS/STAT (SAS Institute, Inc., Cary, NC, USA) and the direction of motion was compared by the t test's LSD. There was no effect of species and treatment, and no species-by-treatment interaction. The direction of motion of microspheres was consistently toward the uterus (pro-uterine) for G1 (0.80 ± 0.20), G2 (1.00 ± 0.00), G3 (1.00 ± 0.00), and G4 (1.00 ± 0.33; P > 0.05). Analyzing the main effects, bovine presented score (0.94 ± 0.05) similar to that of buffalo (1.00 ± 0.17; P > 0.05). Animals treated without estradiol (0.92 ± 0.08) showed the same score as animals treated with estradiol (1.00 ± 0.12). In conclusion, the presence of estradiol-17² in culture medium had no effect on the oviduct ciliary currents in bovine and buffalo.

This work was supported by FAPESP (02/03245-1; 03/00798-1), SPVS, Syntex, Cultilab, and Tecnopec.