Abstract
Overexpression of growth hormone (GH) in gh-transgenic zebrafish of a highly studied lineage F0104 has earlier been reported to cause increased muscle growth. In addition to this, GH affects a broad range of cellular processes in transgenic fish, such as morphology, physiology, and behavior. Reports show changes such as decreased sperm quality and reduced reproductive performance in transgenic males. It is hypothesized that microRNAs are directly involved in the regulation of fertility potential during spermatogenesis. The primary aim of our study was to verify whether gh overexpression disturbs the sperm miRNA profile and influences the sperm quality in transgenic zebrafish. We report a significant increase in body weight of gh-transgenic males along with associated reduced sperm motility and other kinetic parameters in comparison to the non-transgenic group. MicroRNA transcriptome sequencing of gh-transgenic zebrafish sperms revealed expressions of 186 miRNAs, among which six miRNA were up-regulated (miR-146b, miR-200a-5p, miR-146a, miR-726, miR-184, and miR-738) and sixteen were down-regulated (miR-19d-3p, miR-126a-5p, miR-126b-5p, miR-22a-5p, miR-16c-5p, miR-20a-5p, miR-126b-3p, miR-107a-3p, miR-93, miR-2189, miR-202–5p, miR-221–3p, miR-125a, miR-125b-5p, miR-126a-3p, and miR-30c-5p) in comparison to non-transgenic zebrafish. Some of the dysregulated miRNAs were previously reported to be related to abnormalities in sperm quality and reduced reproduction ability in other species. In this study, an average of 134 differentially expressed miRNAs-targeted genes were predicted using the in silico approach. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis demonstrated that the genes of affected pathways were primarily related to spermatogenesis, sperm motility, and cell apoptosis. Our results suggested that excess GH caused a detrimental effect on sperm microRNAome, consequently reducing the sperm quality and reproductive potential of zebrafish males.
Highlights
Since the first proposal to use zebrafish (Danio rerio) in research (Creaser, 1934), the species have attained global popularity as an experimental model organism (Streisinger et al, 1981), and its use in science has grown and continues to grow rapidly (Kinth et al, 2013; Teame et al, 2019)
The results obtained through the Computer Assisted Sperm Analysis (CASA) to evaluate sperm motility demonstrated that gh + individuals had low total motility (Figure 1C) and lesser duration of spermatozoa motility (Figure 1D) when compared to the NT individuals (P < 0.0001)
To the best of our knowledge, the present study is the first to demonstrate the effects of growth hormone (GH) overexpression on the microRNAome profile of sperm cells in gh + transgenic zebrafish
Summary
Since the first proposal to use zebrafish (Danio rerio) in research (Creaser, 1934), the species have attained global popularity as an experimental model organism (Streisinger et al, 1981), and its use in science has grown and continues to grow rapidly (Kinth et al, 2013; Teame et al, 2019). 32 wild strains, such as AB, Tübingen long-fin, and Tüpfel longFin, are currently used (which excludes the local pet shop variants) in various studies (van den Bos et al, 2020; Silveira et al, 2021).. 32 wild strains, such as AB, Tübingen long-fin, and Tüpfel longFin, are currently used (which excludes the local pet shop variants) in various studies (van den Bos et al, 2020; Silveira et al, 2021).1 These reports show more than 115,000 genetic alterations done in zebrafish, of which more than 47,000 are transgenic insertions (Ruzicka et al, 2019). Animal cells can be artificially labeled for easy visualization (Ingham, 2009)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
