Defects in canine sperm motility associated with telomere shortening and changes in expression of shelterin genes

Abstract Background Motion quality is a critical property of sperm to do its essential functions. Several endogenous and exogenous factors are involved in sperm motility. Here, we, for the first time, measured the relative telomere length and evaluated the gene expression of its binding-proteins, as shelterin complex (TRF1, TRF2, RAP1, POT1, TIN2, and TPP1) in sperm of dogs using relative quantitative real-time PCR and compared them between two sperm subpopulations with low and high motion qualities (separated by swim-up method). Telomere shortening and alterations of shelterin gene expression result from ROS, genotoxic insults, and genetic predisposition. Results Sperm kinematic parameters were measured in two subpopulations and then telomeric index of each parameter was calculated. Telomeric index for linearity, VSL, VCL, STR, BCF, and ALH were significantly more in the up-sperms group (high quality) than the down-sperms (low quality) group. We demonstrated that low motion quality is associated with shorter telomere, higher expression of TRF2, POT1, and TIN2 genes, and lower expression of the RAP1 gene in dog sperm. Expression of TRF1 and TPP1 genes was stable with changing of sperm quality and telomere length. Conclusion Data provided evidence that there are considerable changes in gene expression of many shelterin components (TRF2, TIN2, POT1and RAP1) associated with shortening telomere in the spermatozoa with low motion quality. Possibly, the downward motion quality is the result of defects in the shelterin complex and telomere length. Our data suggests a new approach in the animal semen assessment and etiologic studies of animal male infertility.