Lipid Peroxidation and Its Role in the Expression of NLRP1a and NLRP3 Genes in Testicular Tissue of Male Rats: a Model of Spinal Cord Injury

BAckground: The majority of male patients with spinal cord injury (SCI) suffer from infertility. Nucleotide-binding oligomerization domain-like receptors NOD-like receptors (NLRs) are a kind of receptors that corporate in the inflammasome complex. Recent studies have introduced the inflammasome as the responsible agent for secreting cytokines in semen. Reactive oxygen species (ROS) is one of the elements that trigger inflammasome activation. Genital infections in SCI can lead to ROS generation. We investigated the relation between lipid peroxidation and inflammasome complex activity in testicular tissue of SCI rats.

Methods: Adult male rats (n=20), weighting 200-250 g, were included and divided into four groups: three experimental groups, including SCI1, SCI3, and SCI7, i.e. the rats were subjected to SCI procedure and sacrificed after one, three, and seven days, respectively and a control group. We performed a moderate, midline spinal contusion injury at thoracic level 10. The animals were anesthetized, and testes were collected for measurement of gene expression by real-time PCR. Caudal parts of epididymis were collected for malondialdehyde (MDA) measurement.

Results: No NLRP1a mRNA over expression was seen in the testes of control and SCI groups. After seven days from SCI surgery, NLRP3 mRNA expression was significantly increased in SCI7 animals (P≤0.05). There was a significant difference in MDA level in SCI7 versus control group, as well as SCI1 and SCI3 animals (P≤0.05).

Conclusion: NLRP3 overexpression occurs due to the increased ROS production in testicular tissue of SCI rats.