Abundance of selected genes implicated in testicular functions in Camelus dromedarius with high and low epididymal semen quality.

Studying testicular genes' expression may give key insights into precise regulation of its functions that influence epididymal sperm quality. The current study aimed to investigate the abundance of candidate genes involved in the regulation of testicular functions specially those regulate sperm function (PLA2G4D, SPP1, and CLUAP1), testicular steroidogenic function (ESR1 and AR), materials transport (AQP12B and LCN15), and defense mechanisms (DEFB110, GPX5, SOCS3, and IL6). Therefore, blood samples and testes with epididymis were collected from mature middle-aged (5-10 years) dromedary camels (n = 45) directly prior and after their slaughtering, respectively, during breeding season. Sera were evaluated for testosterone level and testicular biometry was measured with caliper. The epididymal tail semen was evaluated manually. Samples were distinguished based on testosterone level, testicular biometry, as well as epididymal semen features into high and low fertile groups. Total RNA was isolated from testicular tissues and gene expression was done using Quantitative Reverse Transcription Polymerase Chain Reaction (qRT-PCR). Results revealed that testosterone levels were significantly (P < 0.005) higher in camels with good semen quality than those of low quality. There was a significant (P < 0.0001) increase in testicular weight, length, width, thickness, and volume in high fertile than low fertile camels. PLA2G4D, SPP1, CLUAP1, ESR1, AR, AQP12B, LCN15, DEFB110, GPX5, and SOCS3 genes were upregulated (P < 0.001), and IL6 gene was downregulated (P < 0.01) in the testes of high fertile camels compared to the low fertile one. Thus, it could be concluded that examined genes might be valuable monitors of testicular functional status and fertility in dromedary camels.

Region-specific gene expression profile in the epididymis of high- and low-fertile dromedary camels.

The scenario of the fertile spermatozoa with high fertilizing capability is basically dependent on gene expression-based epididymal function. The current investigation aimed to declare the varied expression of different candidate genes (PLA2G4D, LCN15, CLUAP1, SPP1, AQP12B, DEFB110 and ESR1) relevant to spermatozoa features between the different epididymal segments in the mature dromedary camels (n = 30). Scrotal contents were collected post-slaughtering, during the breeding season and the epididymis was separated from the testicles and divided into three segments (caput, corpus and cauda) based on its morphology and anatomical characteristics. Epididymal spermatozoa were harvested from each epididymal portion and evaluated for motility, count, viability and morphology. Samples were grouped depending on their epididymal sperm cells features into high-fertile (n = 15) and low-fertile (n = 15) groups. The gene expression of the candidate genes was defined in the isolated RNA from each epididymal portion tissue. The segmental sperm motion and count were significantly (p < .05 and p < .01) higher in the three epididymal parts of high-fertile camels than the lower ones. There were some candidate genes markedly up-regulated in its expression in epididymal head of high-fertile camels (PLA2G4D and LCN15) and low fertile (CLUAP1), while others in the body region of the high-fertile group (SPP1, AQP12B and DEFB110). Nevertheless, ER1 did not differ in the expression among the epididymal segments. In conclusion, the variant expression patterns of these epididymal genes in relation to the regional spermatozoa features might suggest important roles of these genes in sperm maturation process in the epididymis and focusing more interest on their potential utility as markers for male camel fertility prediction.