Hormone measurements and histomorphological observations in male Bactrian camels

The aim of this study was to investigate the effect of age on the hypothalamic-pituitary-gonadal (HPG) axis hormones and to determine the morphological changes of the testis. The Bactrian camels were divided into two groups based on their ages. The results showed that the testicular weight was significantly heavier in adult male camels than in pubertal male camels (P < 0.05). There were also significant differences between testicular length, testicular width, and testicular volume (P < 0.05). In the testes of both pubertal and adult male camels, Sertoli cells, spermatogonia, spermatocytes, round spermatids, and elongated spermatids were observed. Adult male camels had more Sertoli cells (P < 0.01) and elongated spermatids (P < 0.05). The concentrations of testosterone, follicle-stimulating hormone (FSH), and luteinizing hormone (LH) were higher in the plasma and testes of adult camels than in pubertal camels (P < 0.05). E2 concentrations were lower in adult camels than in pubertal camels (P < 0.05). The testosterone levels in testicular tissue were higher than in blood plasma in both adult and pubertal stage (P < 0.05). In conclusion, these findings provide supportive knowledge and show the significant differences in terms of testicular volume, testicular hormone concentrations, and testicular morphology between different developmental stages in Bactrian camels.

Differential expression and localisation of heat shock protein 70 (HSP70) and glutathione peroxidase 5 (GPX5) in the testis and epididymis of Sonid Bactrian camels

CONTEXT

Heat shock protein 70 (HSP70) and glutathione peroxidase 5 (GPX5) are biomarkers of oxidative stress and stress in temperate, tropical environments, which are crucial for male reproduction. Their expression and distribution patterns in the testis and epididymis of Bactrian camels are still unknown.

AIMS

This study aims to investigate the HSP70 and GPX5 expression and localisation in 3- and 6-year-old Bactrian camel testis and epididymis.

METHODS

Reverse transcription quantitative polymerase chain reaction (qRT-PCR), Western blot and immunohistochemistry were used to detect HSP70 in the testis and epididymis (caput, corpus and cauda) and GPX5 in the epididymis at two developmental stages (3-year-old puberty group and 6-year-old adult group).

KEY RESULTS

HSP70 was upregulated in the testis. Immunohistochemistry results indicated the HSP70 protein was mainly detected in spermatids and Leydig cells of testicular tissue. In the epididymis, HSP70 was located at the luminal spermatozoa, the epithelium lining the epididymal and the epididymal interstitium. GPX5 expression was significantly higher in the caput epididymis than in the corpus and cauda epididymis. GPX5 protein was observed in the epithelium lining the epididymal, interstitium and luminal spermatozoa in the epididymis by immunohistochemistry.

CONCLUSIONS

Bactrian camel HSP70 and GPX5 exhibited spatiotemporal expression specificity.

IMPLICATIONS

HSP70 and GPX5 may be essential for germ cell development and reproductive success after sexual maturation in Sonid Bactrian camels.

Whole transcriptome sequencing reveals core genes related to spermatogenesis in Bactrian camels

Bactrian camels survive and reproduce better in extreme climatic conditions than other domestic animals can. However, the reproductive efficiency of camels under their natural pastoral conditions is low. Several factors affect mammalian reproductive performance, including testicular development, semen quality, libido, and mating ability. Testis is a main reproductive organ of the male and is responsible for producing spermatozoa and hormones. However, our understanding of the expression patterns of the genes in camel testis is minimal. Thus, we performed total RNA-sequencing to investigate the gene expression pattern. As a result, 1,538 differential expressed mRNAs (DEmRNAs), 702 differential expressed long non-coding RNAs (DElncRNAs), and 61 differential expressed microRNAs (DEmiRNAs) were identified between pubertal and adult Bactrian camel testes. Then the genomic features, length distribution, and other characteristics of the lncRNAs and mRNAs in the Bactrian camel testis were investigated. Target genes of the DEmiRNAs and DEmRNAs were further subjected to gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses. Genes, such as AMHR2, FGF1, ACTL7A, GATA4, WNT4, ID2, LAMA1, IGF1, INHBB, and TLR2, were mainly involved in the TGF-β, PI3K-AKT, Wnt, GnRH, and Hippo signaling pathways which relate to spermatogenesis. Some of the DEmiRNAs were predicted to be associated with numerous DElncRNAs and DEmRNAs through competing endogenous RNA (ceRNA) regulatory network. At last, the candidate genes were validated by RT-qPCR, dual fluorescent reporter gene, and a fluorescence in situ hybridization (FISH) assay. This research provides high-throughput RNA sequencing data of the testes of Bactrian camels across different developmental stages. It lays the foundation for further investigations on lncRNAs, miRNAs, and mRNAs that involved in Bactrian camel spermatogenesis.