Effect of obesity on human sperm phospholipase C zeta activation

Obesity is associated with low fertility potential in men. Increased visceral adiposity affects steroidogenesis and spermatogenesis locally and peripherally. Ca2+ oscillations are known to be triggered after sperm oocyte membrane fusion, which allows entry of a sperm-specific PLC isoform, termed PLC-Zeta, into the oocyte cytoplasm. Obesity and sperm parameters, and obesity and sperm DNA damage have been shown in previous studies. Our aim was to examine sperm PLC-Zeta expression changes in obese and non-obese men along with sperm parameters. After obtaining consent from the patients who came to Pamukkale University Hospital Andrology Laboratory, the demographic characteristics of the patients were questioned. The patients included in the study were divided into two groups: Control group: Non-obese patients (BMI<30) who gave spermiogram analysis (n: 49) and the Obese Patient Group (BMI≥30) n=18). Semen analysis of the groups was performed. Semen samples were evaluated according to 2021 World Health Organization (WHO) criteria. rt-PCR analysis for PLC-Zeta expression and histopathologic evaluation by immunohistochemistry were performed. Testosterone levels in the control group were statistically higher than in the obese group (4.8±1.28; 3.6±1.61, respectively) (p<0.05). Prolactin levels were 12.6±7.2 in the control group and 17.15±9.28 in the obese group, which was statistically significant (p=0.031). No significant difference was detected between the groups in semen analysis. PCR determined that PLC-Zeta expression increased 1.69 times in obese patients compared to the control group. This increase was opposite of our findings by immunohistochemical staining which showed a decrease of PLC-Zeta in obese patients. In conclusion, our study showed that obesity may cause a defect in PLC-Zeta expression at the protein synthesis and translation stage, but not at the mRNA expression level. However, further studies with an increased number of patients are needed to obtain clear information