Improving the quality and the developmental competence of in vitro produced (IVP) embryos is an indispensable goal for assisted reproductive technology. Autophagy is a major protective mechanism for intracellular degradation of unnecessary cytoplasmic components. Autophagy ends by the fusion between autophagic vacuoles and lysosomes, allowing the degradation of the cargo by lysosomal enzymes, especially the cathepsins (CTSs). However, it is still unclear how autophagy and cathepsin K (CTSK) relate to embryo development. This study evaluated (1.) the activities of autophagy and CTSK in relation to bovine embryo quality and (2.) the effect of autophagy induction and/or CTSK inhibition on preimplantation embryo development and quality. We show here that good-quality embryos exhibited a greater autophagic activity and less CTSK activity compared to poor-quality embryos. Blastomeres of an individual embryo may vary in their quality. Good quality blastomeres showed an increased autophagic activity and decreased CTSK activity compared to poor-quality blastomeres within the same embryo at different developmental stages. Importantly, induction of autophagy and/or inhibition of CTSK improved the developmental rate (increased blastocyst and hatching rates) and the quality (increased total cell number and decreased the percentage of apoptotic cells) of IVP bovine embryos. These results demonstrate a promising approach to selectively isolate good-quality embryos and improve the efficiency of IVEP of cattle embryos.

The reproductive ability of male animal is dependent to a great extent on the effective functions of the genital glands. The present study was carried on the pelvic urethra of 32 sexually mature male donkeys. 5µm sections were prepared from the samples and stained with different stains to show the different structures of the pelvic urethra. Scanning electron microscopic studies were performed on the lumen of the pelvic urethra to show the different shape of the urethral gland opening on the surface layer of the lamina epithelialis of the pelvic urethra. The pelvic urethra of donkey is formed of prostatic and membranous parts. The lamina epithelialis of the pelvic urethra varied at its different regions. The urethral glands were observed along the entire length of the pelvic urethra within the lamina propria-submucosa. They were mostly of the branched tubulo-alveolar glands lined by high cuboidal or pyramidal-shaped epithelial cells. The activity of the urethral glands in donkey varied throughout the year. It was more pronounced during spring, which was manifested by increased epithelial height, decreased nuclear/cell ratio, decreasing interstitial connective tissue/glandular tissue ratio and increased cellular secretory activity. This activity decreased gradually during the summer and autumn to reach its minimal level during winter.