The Effect of Carboxymethyl Cellulose on Gene Expression Related with Apoptosis, Cold Shock, Motility and Reactive Oxygen Species of Cryopreserved Dog Sperm

Carboxymethyl cellulose (CMC) can act as a nonpermeating cryoprotectant, reducing the toxicity of glycerol. The dog spermatozoa were diluted and frozen in freezing extender supplemented with 0 (control), 0.1, 0.25, 0.5, or 0.75 % (w/v) CMC. Post-thaw, the sperm kinematic parameters (CASA), viability (SYBR-14/PI), and acrosome integrity (FITC-PSA) were evaluated. The expression of genes related to apoptosis (BCL2, BAX, and ANAXA), motility (BACTIN), cold shock proteins (YBX3), and ROS (CAT, ROMO1, and SMOX) was evaluated using qPCR. The total motility was higher in the 0.1 % CMC group compared to the other groups (p<0.05). In addition, the expression of the antiapoptotic gene BCL2 was upregulated in 0.1 % CMC group compared to the control, whereas the gene expression of BAX and SMOX exhibited lower levels in 0.1 and 0.25 % CMC groups than the control group (p<0.05). The expression of YBX3 genes was significantly decreased with 0.25 % CMC supplementation. No significant differences were found in viability, acrosome integrity, or the relative expression of ANAXA, BACTIN, CAT, and ROMO1 genes between the groups. In conclusion, the addition of CMC to a freezing extender improved sperm motility and alleviated cryostress by regulating the gene expression of BCL2, BAX, SMOX, and YBX3.