The effect of carboxymethyl cellulose on gene expression related to apoptosis, cold shock, motility, and reactive oxygen species of cryopreserved dog sperm

BACKGROUND: Carboxymethyl cellulose (CMC), a cellulose derivative, is osmotically inert and has low viscosity compared with other non-permeating cryoprotectants. OBJECTIVE: To assess whether a combination of CMC with glycerol can improve the efficiency of freezing extender for dog sperm cryopreservation. MATERIALS AND METHODS: 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), plasma membrane integrity (SYBR14/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. RESULTS: 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 the 0.1% CMC group compared to the control, whereas the gene expression of BAX and SMOX exhibited lower levels in the 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. 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.