Histomorphometric Evaluation Of Type I And III Collagen in the Anterior Cruciate Ligament of Human Fetuses
A.F. Leitao Junior, J.A.D. Leite, V.T.F. Leitão, P.G.T. De Sousa Filho, M.L.C. CavalcanteObjective:
To evaluate the histomorphometry of type I and type III collagen in the anterior cruciate ligament (ACL) of human fetuses, comparing the tibial insertion, ligament body, and femoral insertion regions.
Methods:
Ten anterior cruciate ligaments from six human fetuses, with gestational ages ranging from 21 to 37 weeks, were analyzed. Each ligament was divided into three regions: tibial insertion (field I), ligament body (field II), and femoral insertion (field III). Samples were stained with Picrosirius Red and evaluated using polarized light microscopy. Quantification of type I and III collagen was performed via digital histomorphometry using ImageJ® software. Statistical analysis employed the Friedman test followed by Dunn’s post-test, with a significance level of 5% adopted.
Results:
Type I collagen was predominant in all analyzed regions. In field I, mean values were 65.51% for type I collagen and 21.03% for type III collagen. In field II, mean values of 56.75% and 25.44% were observed, respectively. In field III, mean values were 60.59% for type I collagen and 23.54% for type III collagen. A statistically significant difference was found in the distribution of type I collagen between fields I and II (p < 0.05), with greater predominance at the tibial insertion. No significant difference was observed for type III collagen.
Conclusion:
The fetal ACL exhibits a distinct regional distribution of type I and III collagen, suggesting structural differences associated with the ligament’s biomechanical properties as early as the fetal period.