The effect of rapid freezing on the expression of SPAG5 and SPAG9 in human spermatozoa

Sperm associated antigens (SPAGs) play an important role in the incidence of various cancers including breast, lung, liver, and bladder. SPAGs are also important in sperm functions, such as motility. However, it seems that sperm cryopreservation as one of the assisted reproductive techniques (ART), can affect the expression of these genes. This study aimed to evaluate the effect of freezing on the expression of human SPAG 5 and 9 in human spermatozoa.

In the present experimental study, twelve semen samples in terms of normozoospermic parameters were collected from individuals referred to the Royan Institute, and progressive motile sperms were isolated by density gradient centrifugation (DGC). Each sample was divided into two, non-frozen (control) and frozen groups. After rapid freezing and three-day storage in liquid nitrogen, samples were thawed in tap water and incubated for 2 hours of recovery-time in a CO2 incubator. RNA extraction in both groups was performed using TRIzol; and SPAG5 and 9 were evaluated by Real-time PCR technique.

Based on statistical analysis, the expression of SPAG5 decreased significantly in the frozen group compared to the control group (P≤0.05); In contrast, there was no significant difference in the expression of SPAG9 between the control and frozen groups.

Considering the cold shock in the future of cell, a significant reduction in SPAG5 expression in the frozen group may indicate probable influences in the derived fetus.