Ciliogenesis in the Uterine Tube of Control and Superovulated Heifers

Abstract

Ciliogenesis was investigated in the uterine tube epithelium of control and superovulated heifers during day 1 to day 7 of the oestrous cycle. Seventy-two heifers were used, consisting of four control groups and four superovulated groups. All heifers received cloprostenol (PG) to induce oestrus (day 0). Superovulated heifers received 24 mg pFSH at doses of 4.5, 3.5, 2.5 and 1.5 mg given twice daily. Control and superovulated heifers were slaughtered on days 1, 3, 5 and 7 of the oestrous cycle. Samples from the ampulla, preisthmus and isthmus of the uterine tube were collected and processed for light and electron microscopy, following standard procedures. Both centriolar and acentriolar pathways were involved in the development of basal bodies. Formation of basal bodies and protrusion of ciliary shafts mostly occurred during days 1 and 3 of the oestrous cycle. The centriolar pathways, in which procentrioles generate with the aid of preexisting centrioles, played a minor role in the heifer uterine tube. In the acentriolar pathways, fibrous granules were the first structures which appeared in the course of ciliogenesis and they initially occurred in association with free ribosomes. Subsequently, deuterosomes arose in the aggregates of fibrous granules, and then procentrioles containing microtubules originated around deuterosomes or apart from deuterosomes. Newly formed centrioles migrated to the apical cytoplasm, and ciliary shafts extended first at the periphery of the luminal surface of ciliogenic cells. Deuterosomes as well as rootlet formation were considered to be related to the fibrous granules. Quantitative examinations by light microscopy showed that the number of ciliated cells in the ampullar, preisthmic and isthmic epithelium of the superovulated heifers was significantly higher than in the control heifers during day 1 and day 3 of the oestrous cycle.