Protamine Ratio as Predictor of the Fertility Potential of Sperm by Couple Undergoing ICSI

The present study aimed to measure the protamines P1 and P2 concentrations, standard sperm parameters, and also DNA fragmentation and condensation. In addition, the correlations between the above-mentioned variables and the P1/P2 ratio were explored in order to find out whether the ratio could be used as a biomarker for semen quality. A total of 272 semen samples were divided into 3 P1/P2 ratio groups: G1 as low (<0.8), G2 as normal (0.8-1.2), and G3 as high (>1.2) ratios. DNA fragmentation and condensation were evaluated by TUNEL and CMA3 (chromomycinA3) assays and protamine levels (P1 and P2) were measured using acid urea polyacrylamide gel (AU-PAGE) electrophoresis and western blot (WB). In G1, CMA3 positive and DNA fragmentation index (DFI) were negatively correlated (r = -0.371, P = 0.001). In addition, P1/P2 ratio had a positive correlation with DFI (r = 0.652, P = 0.001);however it had a negative association with CMA3 (r = -0.623, P = 0.001). Moreover, G2 demonstrated positive correlations between sperm concentration and P1(r = 0.257, P = 0.011) and P2 (r = 0.277, P = 0.006), progressive motility, and P1 (r = 0.352, P = 0.001). The P2 was positively correlated with progressive motility (r = 0.380, P < 0.01). Besides, a positive relationship was found between P1/P2 ratio and CMA3 (r = 0.333, P = 0.001). In contrast, normal morphology showed a negative association (P < 0.05) with P1 (r = -0.206) and P2 (r = -0.208).Meanwhile, there was a negative correlation between P1 and DFI (r = -0.207, P = 0.041) as well. Finally, in G3, negative correlations were also observed between P1 and normal morphology (r = -.283, P = .027) and also P1/P2 ratio and P2 (r = -0.372, P = 0.003) while DFI showed a positive correlation with CMA3 (r = 0.299, P = 0.019). The results revealed that P1/P2 ratio affected DNA integrity. Therefore, it was found that it could play a crucial role in human sperm quality and function and thus might be used as a predictor of fertility in assisted reproductive technology (ART) treatments.