Expressions of calpain-1, ubiquitin and 20S proteasome in congenital muscular torticollis

Abstract

Objective To detect the expressions of calpain-1,ubiquitin and 20S proteasome in sternocleidomastoid muscle (SCM) of the patients with congenital muscular torticollis (CMT).Methods CMT group consisted of 40 patients aged from 4 months to 16 years old who were randomly chosen from 188 CMT patients.According to their age,these patients were divided into 4 groups with 10 in each:group 1 included patients aged from 4 to 6 months old; group 2 was 7 to 12 months old;group 3 was 1 to 3 years old; and group 4 was 4 to 16 years old.Five specimens collected from adductor muscle,including 1 from the patient with cerebral palsy and the other 4 from development dysplasia of the hip,were taken as control group.All resected surgical specimens vere processed for H&.E staining,Masson and immunohistochemical staining for calpain 1,ubiquitin and 20S proteasome.Results Atrophic muscle fibers were noted in all 40 CMT patients.Adipose hyperplasia was noted in 29patients with CMT.The percentage of strongly calpain-1-positive fibers in CMT group was significantly higher than that of controls (40.7％±13.8％ vs.0.52％± 0.54％,P＜0.001 ),and was positively correlated with the level of fibrosis (r=0.750,P＜0.001 ).The percentage of strongly ubiquitin and 20S proteasome positive fibers in CMT group was significantly higher than that of controls (43.7％±14.7％,32.4％±12.5％ vs.1.1％±0.63％,0.62％±0.40％,P＜0.001,respectively),and was positively correlated with the level of fibrosis (r=0.758,P＜0.001 ; r=0.571,P＜0.001,respectively).The level of calpain-1 was positively correlated with ubiquitin (r=0.956,P＜0.001 ).The level of ubiquitin was positive correlated with 20S proteasome (r=0.786,P＜0.001 ).Conclusions Muscle atrophy and adipose hyperplasia are the basic pathological changes in CMT.The calpain and ubiquitin-proteasome dependent proteolytic pathway may play a role in muscle atrophy of CMT. Key words: Torticollis; Muscular atrophy