ABSTRACT
Cathepsin D (CTSD), the major lysosomal aspartic protease that is widely expressed in different tissues, potentially regulates the biological behaviors of various cells. Follicular granulosa cells are responsive to the increase of ovulation number, hence indirectly influencing litter size. However, the mechanism underlying the effect of CTSD on the behaviors of goat granulosa cells has not been fully elucidated. This study used immunohistochemistry to analyze CTSD localization in goat ovarian tissues. Moreover, western blotting was applied to examine the differential expression of CTSD in the ovarian tissues of monotocous and polytocous goats. Subsequently, the effects of CTSD knockdown on cell proliferation, apoptosis, cell cycle, and the expression of candidate genes of the prolific traits, including bone morphogenetic protein receptor IB (