Análise microtomográfica e de expressão gênica do crescimento craniofacial após supressão de testosterona : um estudo in vivo

Abstract

Craniofacial bone development is influenced by various factors, including sex hormones. Changes in testosterone levels affect craniofacial growth, and consequently, facial aesthetics and masticatory function. The aim of this study was to evaluate the impact of testosterone suppression on cranial growth and development in rats during puberty. Testosterone suppression was induced by orchiectomy (ORX) in male Wistar rats in the experimental group (n=18), while a sham operation (SHAM) was performed in the control group (n=18), both on the 23rd day of life. The groups were euthanized at 45 and 73 days of life. Micro-computed tomography (micro-CT) analysis and molecular marker expression assays were conducted on samples from both experimental time points. Data from the micro-CT analyses were compared using the Mann-Whitney test, with IBM SPSS Statistics software. Gene expression analysis of biomarkers related to OC, OPN, RUNK2, MMP2 and MMP9, involved in osteogenesis, was performed in the retro molar region, condylar region, and palatal suture using the RT-PCR technique. Values were compared between groups using ANOVA followed by Bonferroni post-test. All results were considered statistically significant at p<0.05. Micro-CT analysis revealed no significant differences in bone volume/total volume (BV/TV), trabecular connectivity (Conn. D), trabecular thickness (Tb. Th), or trabecular spacing (Tb. Sp.) in the condylar and palatal regions (p>0.05). Linear and angular measurements showed differences between the ORX and SHAM groups, such as an increase in maxillary bone length in the ORX group (45-day sample) and an increase in mandibular width in the SHAM group (73-day sample) (p<0.05). In RT-PCR analysis, the ORX group exhibited the following: in the retro molar region, higher expression of OC, MMP2, and RUNX2 genes, lower expression of OPN and MMP9 in the 45-day sample, and lower expression of OC, OPN, RUNX2, MMP2, and MMP9 in the 73-day sample (p<0.05); in the condylar region, only lower RUNX2 expression was observed (p<0.05) in the 45-day sample; in the palatal suture region, there was lower expression of OC, OPN, RUNX2, MMP2, and MMP9 in the 45-day sample, and lower expression of OC, RUNX2, MMP2, and MMP9 in the 73- day sample (p<0.05). The results indicate that testosterone suppression alters cranial linear/angular measurements and suggests more expressive changes in the direction of bone growth than in bone size and quality. It also alters the gene expression of osteogenic biomarkers in cranial bone growth centers.