Bacterial contamination is unavoidable during the storage of boar semen. Antibiotics or chemicals in the semen extender do not clear lipopolysaccharide (LPS) released from the Gram-negative bacteria. LPS undermines sperm functionality and efficacy of semen preservation in vitro. Spermine and spermidine, natural polyamines in seminal plasma, are considered to be a class of immunomodulatory factors. In the present study, we found, for the first time, that spermine and spermidine alleviate LPS-induced boar sperm mitochondrial dysfunction and apoptosis in a casein kinase 2-dependent manner. Spermine and spermidine also maintain sperm quality during liquid preservation in vitro. The data from the present study provide novel insights into the protection of porcine sperm against LPS-induced injury and improvement of the efficiency of semen preservation in pigs and potentially in other domestic animals.

Read the full article in the Journal of Animal Science.