56 COMPARISON OF THE MORPHOLOGY OF VARIOUS REGIONS OF THE CATTLE OVIDUCT IN FOUR PHASES OF THE OVARIAN CYCLE

Abstract

The oviduct provides the environment necessary for the gamete transport, completion of spermatozoa capacitation, oocyte fertilization and the early development of embryos. In cattle, all of these processes take place between Day 0 to 4 of the ovarian cycle (Day 0 is the day of ovulation). In previous studies, temporal changes in the bovine oviduct morphology were evaluated by dividing the ovarian cycle into luteal and follicular phases. In order to understand the relation between the bovine oviduct morphology and processes occurring there, the ovarian cycle has been further divided into four phases: I (Day 0–4), II (Day 5–10), III (Day 11–17) and IV (Day 18–20), with the day of ovulation considered Day 0 (1980 J. Dairy Sci. 63, 155–160). The aim of the study was to evaluate the oviduct morphology of the infundibulum, ampulla and isthmus in 4 phases of the ovarian cycle. Research material comprised cattle oviducts (classified into 1 of the 4 phases of the cycle based on ovarian morphology), dissected into infundibulum, ampulla and isthmus and subsequently sectioned and processed for histological preparations (hematoxylin and eosin, H&E, staining). Diameters of transverse cross-sections of oviduct and its lumen and thickness of tunicas: mucosa, muscularis and serosa were evaluated in relation to the region of oviduct and the phase of ovarian cycle. Values are given in μm. Statistical analysis was carried out by 1-way analysis of variance and comparisons of mean values were made with the Tukey honestly significant difference test (Statgraphics Plus 5); P < 0.05 was considered to reflect the presence of statistical significance. The comparison of the diameters of transverse cross-sections (A) of oviduct and its lumen (B) shows significant statistical differences between ampulla and isthmus within the phases: A-I (4507.26 vs 2524.47), II (4510.53 vs 2540.67), III (4503.28 vs 2534.07), IV (4500.73 vs 2533.90); B-I (4191.10 vs 1950.88), II (4173.63 vs 1986.33), III (4198.53 vs 1966.88) and IV (4192.50 vs 1959.33). There are no differences among 4 phases of the ovarian cycle. The thickness of tunicas muscularis and serosa of infundibulum (I: 26.81 vs 196.85; II: 27.03 vs 201.80; III: 26.22 vs 199.45; IV: 23.97 vs 198.01), ampulla (I: 91.51 vs 214.50; II: 90.72 vs 212.55; III: 88.61 vs 213.30; IV: 89.65 vs 206.28) and isthmus (I: 202.29 vs 216.52; II: 199.24 vs 207.74; III: 200.90 vs 212.38; IV: 200.38 vs 210.86) show only statistically significant differences within the phases, whereas the tunica mucosa shows only statistically significant differences between phases and the term of the height of epithelium at the base of mucosal folds (I: 26.49; II: 25.20; III: 24.14; IV: 29.96) and their apical parts (I: 28.09; II: 26.01; III: 25.45; IV: 30.96). In conclusion, differences in oviduct morphology are mainly region specific, whereas the epithelium morphologically infundibulum, ampulla and isthmus show variation in the 4 phases of the ovarian cycle. Supported by Grant MNiSW N311236137.