Abstract
BACKGROUND This study investigated the expression of Bax/Bcl-2, TGF-β1 and type III collagen fiber in sternocleidomastoid of congenital muscular torticollis (CMT), and explored the possible mechanisms of fibrosis in sternocleidomastoid of CMT. MATERIAL AND METHODS The localization and expression of Bax, Bcl-2, TGF-β1, and type III collagen were detected in the control group and experimental group by using immunohistochemical staining method. The RT-PCR assay was used to measure the expression of TGF-β1 in the control group and experimental group. RESULTS HE staining results showed that the collagen fiber in the experimental group had more abundant hyperplasia compared to the control group (p<0.05). Immunohistochemical staining results showed that the expression of Bax, Bax/Bcl-2, TGF-β1, and type III collagen in the experimental group was significantly increased compared to the control group (p<0.01). There were positive correlations between expression of Bax/Bcl-2 and TGF-b1, and between expression of TGF-β1 and type III collagen fiber (p<0.05, r=0.32 and 0.83, respectively). The RT-PCR results showed that the expression of TGF-β1 mRNA was also significantly elevated in the experimental group compared to the control group (p<0.05). CONCLUSIONS Increased muscular apoptosis may aggravate the formation of muscular fibrosis, which may be involved in the pathogenesis of sternocleidomastoid of CMT.