Comparing ovarian expression of sperm acrosome associated 3 protein in young and adult queens

The purpose of this research was to quantify sperm acrosome associated 3 protein expression in the ovaries of young (3.0 ± 0.9 months, n = 11) and adult (10.4 ± 2.8 months, n = 11) queens. Immunohistochemistry was performed on formalin-fixed, paraffin-embedded feline ovarian sections. Ovaries were obtained following routine ovariohysterectomy of queens. Cellular expression of sperm acrosome associated 3 protein was measured in primordial, primary, secondary, and tertiary follicles using an image-analysis software's red, green, and blue stack and manual thresholding functions. The oocyte nucleus, ooplasm, granulosa cells, and theca cells were outlined using the freehand selection tool and mean grey value was recorded. Results from each cellular location were compared between age groups using a Student's t-test and between follicle stages using an analysis of variance. Compared to adult queens, younger queens had significantly greater sperm acrosome associated 3 protein expression in granulosa cells of primary, secondary, and tertiary follicles. Also, theca cells of secondary and tertiary follicles had significantly greater sperm acrosome associated 3 protein expression in younger queens compared to adult queens. The oocyte nucleus of primordial, primary, and secondary follicles had significantly greater sperm acrosome associated 3 protein expression in younger queens compared to adult queens. However, sperm acrosome associated 3 protein expression within the ooplasm did not differ significantly between age groups of any follicle type. More research is needed to determine what role sperm acrosome associated 3 protein may play in female fertility in animals as well as what mechanisms regulate ovarian sperm acrosome associated 3 protein expression over time.