Background
Spermatogenic maturation arrest is thought to be caused by epigenetic defects, specifically in chromatin remodeling and histone modification. This study evaluated the status of chromatin remodeling chromodomain helicase DNA binding protein 5 (CHD5) and histone modifications histone 4 lys-12 acetylation (H4K12ac) and histone 3 lys-9 trimethylation (H3K9me3) in human testicular biopsies, based on maturation arrest type. Materials and
Conclusion
The expressions of CHD5, H3K9me3, and H4K12ac in different spermatogenic cell types produce similar results, indicating that they cannot be used as markers to determine the type of spermatogenic maturation arrest in humans. The significant finding in this research is the expression of CHD5 in human spermatogonia cells, which requires further study for elaboration.
Methods
The cross-sectional study utilized 18 Bouin-fixed paraffin-embedded (BFPE) specimens prepared from residual tissue from routine laboratory tests of infertile patients. The expression of CHD5, H4K12ac, and H3K9me3 was examined through immunohistochemistry (IHC). The intensity was measured using ImageJ with IHC Profiler and StarDist plugins. Statistical analysis was performed using Python with Scipy.Stats module. The data were tested with Shapiro- Wilk for normality and Levene test for homogeneity. The differences in the intensity of spermatogenic cells were assessed using Kruskal-Wallis and Mann-Whitney tests. A difference was considered statistically significant if P<0.05.
Results
We found three types of maturation arrest, including Sertoli cell only (n=5), spermatocyte arrest (n=4), and spermatid arrest (n=9). CHD5 was positive in spermatogonia and round spermatids but absent in spermatocytes. The mean grey value (MGV) of CHD5 in spermatogonia was generally weak in spermatocyte arrest (157.4 ± 16.6) and spermatid arrest (155.3 ± 16.8), and there was no significant difference between them [P=0.49, 95% confidence interval (CI): (-4.3, 6), effect size (r): 0.02]. Although there was a significant difference in the expression of H3K9me3 and H4K12ac (P<0.001), both histone modifications were found in all observed spermatogenic cells.