Human protamines and male infertility
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K K Khara1, M Vlad, M Griffiths
1Molecular Medical Research Group, University of Warwick, Biological Sciences, Coventry, UK.
Purpose:
Our purpose was to determine the ratio of protamine 1 to protamine 2 in human spermatozoa and relate it to in vitro fertilization rates (IVF) and standard semen parameters.
Methods:
Couples who had been clinically diagnosed as having male-factor infertility and had undergone IVF treatment were grouped according to IVF rates and pregnancy outcome. Protamines were extracted and separated on acid urea polyacrylamide gels. The P1/P2 ratio correlation with semen parameters and IVF rates was investigated using nonparametric analysis.
Results:
The P1/P2 ratio ranged from 0.55 to 1.29 in the control group of patients, who had fertilization rates > or = 50% and had achieved a pregnancy in one IVF cycle. Of the test patients with IVF < 50%, three (14%) had P1/P2 ratios outside the range exhibited by the control group and their sperm possessed large heads.
Conclusions:
P1/P2 ratios were statistically negatively correlated with IVF rates in the control group and with progressive motile sperm concentration in the test group. We do not think that altered P1/P2 ratios are the primary cause of reduced fertilization.