Genome-wide transcriptome analysis reveals differentially expressed genes and key signalling pathways associated with cryptorchidism in pigs.

Cryptorchidism, a prevalent congenital defect in pigs, raises animal welfare and economic concerns in the breeding industry. This study utilized a genome-wide transcriptome analysis, examining samples from the pituitary gland, cremaster muscle and testis of one-week-old piglets. In the cremaster muscle of cryptorchid piglets,1225 genes exhibited significant differential expression (log2FoldChange = |2.0|, p-adjusted value ≤ 0.01). Downregulated genes were linked to biological processes like muscle tissue development and actin cytoskeleton organization. Pathway analysis further revealed the suppression of metabolic pathways including 'Oxidative phosphorylation', 'TCA cycle' and 'Motor Proteins'. Notably, several genes integral to the motor protein pathway were significantly downregulated. Additionally, crucial genes in the noncanonical Wnt signalling pathway that regulates tissue morphogenesis and repair during the embryonic stage, were also suppressed. Our results indicate that a disruption in the normal testicular descent is accompanied by the suppression of major genes in the motor protein pathway, potentially hampering the presumed role of the cremaster muscle in testicular descent. However, we propose this to be a consequence of the down regulation of key genes in the noncanonical Wnt signalling pathway. Based on our findings, future research might be able to uncover causal mutations related to the expression of these genes.