Morphological, biochemical, and histopathological alterations in the paraspinal skeletal muscle of patients with adolescent idiopathic scoliosis (AIS) have been extensively reported. We evaluated rotator muscle fibers from the apex vertebra of AIS patients through histological and immunohistochemical analysis.A population of 21 female AIS patients who underwent corrective surgery between 2010 and 2013 had biopsies taken from the paraspinal muscle in the convex and concave sides of the thoracic curve apical vertebra. Serial sections were stained following routine protocols for hematoxylin and eosin (HE), Sudan red, Gomori trichrome, NADH, ATPase, and cytochrome oxidase. We assessed muscular atrophy and hypertrophy, fatty proliferation, endomysial and perimysial fibrosis, the presence of hyaline fibers, mitochondrial proliferation, muscular necrosis, nuclear centralization, and inflammation. Two independent professionals evaluated the slices.The thoracic curves had an average Cobb angle of 68 degree. Comparative analysis of the concave and convex sides was performed with McNemar test at a significance level of 5%. Results showed significant differences in both endomysial and perimysial fibrosis and fatty involution between the two sides of the apex vertebra.Paraspinal muscles in the concave side of the scoliosis apex had significantly more fibrosis and fatty involution. However, both sides showed signs of myopathy, muscular atrophy due to necrosis, presence of hyaline fibers, and mitochondrial proliferation.

OBJECTIVE: The I/D polymorphism of angiotensin-converting enzyme (ACE) and R577X of the α-actinin-3 (ACTN3) is related to changes in skeletal muscle function. The aim of this study was to evaluate the distribution of these polymorphisms in a family with multiple members with adolescent idiopathic scoliosis (AIS). METHODS: Evaluated 25 subjects from a family with multiple members with AIS, by collecting 10mL of blood for DNA isolation. The genotyping of the I/D polymorphism of the ACE gene and the R577X of the ACTN3 gene was performed using two specific primers to classify individuals as homozygous or heterozygous. RESULTS: Regarding the ACE polymorphism it was found that 19 (76%) subjects were DD and 6 (24%) ID. The prevalence of the D allele was 88% and the I allele was 12%. Regarding the ACTN3 polymorphism there were 6 subjects RR (24%), 11 RX (44%) and 8 XX (32%). The prevalence of the R allele was 23 (46%) and the X allele was 27 (54%). CONCLUSION: There was a difference between the distribution of the polymorphism of ACE and ACTN3 in the family studied. When assessing the ACE polymorphism a higher prevalence of the D allele was observed as compared with the I allele. Level of Evidence III, Cross-sectional, Clinical Trial.