OBJECTIVETo investigate the effect of sympathectomy on the development and progression of scoliosis in bipedal C57BL/6J mice model.

METHODSSixty female 3-week-old C57BL/6J mice were selected to establish bipedal scoliotic mice model after amputations of forelimbs and tails. All mice were randomly divided into three groups, 20 mice for each group. Group 1 received daily intraperitoneal injection of 0.9% saline (5 mg/kg); while Group 2 and 3 received sympathectomy by daily intraperitoneal injection of propranolol (20 mg/kg) and guanethidine sulfate (40 mg/kg), respectively. Posteroanterior X-rays were obtained at 20th week. Curves were measured using Cobb method and scoliosis was defined as a Cobb angle of > 10°. Incidence of scoliosis and severity of curves were compared among groups using Chi-square test and One-way analysis of variance, respectively.

RESULTSThere were 17 (85.0%) mice presented scoliosis in Group 1; whereas 11 (55.0%) and 10 (50.0%) mice presented scoliosis in Group 2 and 3, respectively. The incidence of scoliosis was found to be higher in Group 1, and the difference was statistically significant (χ(2) = 6.172, P = 0.046). As for curve magnitudes, the mean Cobb angle was 20° ± 9° in Group 1, 10° ± 7° in Group 2, and 12° ± 8° in Group 3. The mean Cobb angle of Group 1 was significantly greater than those of Group 2 and 3 (F = 9.545, P < 0.001), but there was no significant difference in mean Cobb angle between Group 2 and 3.

CONCLUSIONSSympathetic nervous system may be involved in the development and progression of scoliosis in bipedal C57BL/6J mice model. Sympathectomy do not seem to dramatically decrease the incidence of scoliosis, probably due to that bipedalism itself may also be a cause of scoliosis in this animal model.