Expression of Bax/Bcl-2, TGF-β1, and Type III Collagen Fiber in Congenital Muscular Torticollis

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/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-β1, 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.