Is there a relationship between infertility and fertilin β protein distribution?

Introduction: Fertilin β is a sperm surface protein that can mediate sperm-egg membrane interaction. This study was conducted to determine whether the expression of fertilin β after intrauterine insemination (IUI) in donors with normal parameters after standard semen analysis is related to low success rate or failure of fertilization.

Methods: We examined the sperm of 30 male donors who have normal as controls, oligozoospermia, and unexplained infertility as the clinically indication for IUI. Fertilin β has been labeled with the ADAM2 antibody by indirect immunofluorescence (IF) assay. To evaluate the reproducibility of the test, we selected four sperm samples scale of 0 to +++ according to the distribution of fluorescence label.

Results: The results were highly correlated with the corrected total cell fluorescence (CTCF) (R=0.9972, P<0.05). We suggest that the relationship between infertility and fertilin β may be due to the distribution of this protein on the sperm surface. Male partners of couples with unexplained infertility showed a low distribution of fertilin β by a decrease of the fluorescence signal in the IF labeling (scale of +++ by 7.4±10.32%, P<0.0001, ±SD).

Discussion: Abnormal fertilin β function may be a potential mechanism that could lead to fertilization failure.