# Comparative Analysis of mRNA and lncRNA Expression Profiles in Testicular Tissue of Sexually Immature and Sexually Mature Mongolian Horses

## TL;DR

This study compares gene activity in testes of young and adult Mongolian horses to understand how genes control testicular development and sperm production.

## Contribution

The study identifies and compares mRNA and lncRNA expression profiles in testicular tissues of sexually immature and mature Mongolian horses.

## Key findings

- 16,582 mRNAs and 2128 unknown lncRNAs are commonly expressed in both immature and mature horse testes.
- 9217 mRNAs and 2191 lncRNAs show differential expression between the two age groups.
- Genes in immature horses relate to cell structure, while those in mature horses relate to hormones, metabolism, and sperm production.

## Abstract

This study explored how genes control the testicular development and sperm production in Mongolian horses. We examined the testes of sexually immature and sexually mature Mongolian horses, focusing on two types of genes: mRNA and lncRNA. Using advanced technology, we found 16,582 mRNAs and 2128 unknown lncRNAs active in both sexually immature and sexually mature Mongolian horses. And 9217 mRNAs and 2191 unknown lncRNAs behaved differently between the two age groups. Our further tests showed that young horses’ genes mostly affected basic cell structures, while those of adult horses influenced hormones, metabolism, and sperm production. These findings deepen our understanding of horse testicular development and may guide future research.

Testicular development and spermatogenesis are tightly regulated by both coding and non-coding genes, with mRNA and lncRNA playing crucial roles in post-transcriptional gene expression regulation. However, there are significant differences in regulatory mechanisms before and after sexual maturity. Nevertheless, the mRNAs and lncRNAs in the testes of Mongolian horses have not been systematically identified. In this study, we first identified the testicular tissues of sexually immature and sexually mature Mongolian horses at the tissue and protein levels, and comprehensively analyzed the expression profiles of mRNA and lncRNA in the testes of 1-year-old (12 months, n = 3) and 10-year-old (n = 3) Mongolian horses using RNA sequencing technology. Through gene expression analysis, we identified 16,582 mRNAs and 2128 unknown lncRNAs that are commonly expressed in both sexually immature and sexually mature Mongolian horses. Meanwhile, 9217 mRNAs (p < 0.05) and 2191 unknown lncRNAs (p < 0.05) were identified as differentially expressed between the two stages, which were further validated by real-time fluorescent quantitative PCR and analyzed using Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG). The analysis results showed that genes in the sexually immature stage were mainly enriched in terms related to cellular infrastructure, while genes in the sexually mature stage were enriched in terms associated with hormones, metabolism, and spermatogenesis. In summary, the findings of this study provide valuable resources for a deeper understanding of the molecular mechanisms underlying testicular development and spermatogenesis in Mongolian horses and offer new perspectives for future related research.