Tsubaki T1, Ozawa J2, Yakuwa T3, Inoue S3, Nomura M3,4, Wakimoto Y3, Li C3, Hatakeyama J1, Kinoshita S1, Wakigawa T1, Kito N2, Sakai Y5, Akisue T6, Moriyama H6
1Kobe University, School of Medicine Faculty of Health Sciences, Physical Therapy Major, Kobe, Japan, 2Hiroshima International University, Department of Rehabilitation, Faculty of Rehabilitation, Higashihiroshima, Japan, 3Kobe University, Graduate School of Health Sciences, Department of Rehabilitation Science, Kobe, Japan, 4Research Fellow of Japan Society for the Promotion of Science, Tokyo, Japan, 5Kobe University Graduate School of Medicine, Division of Rehabilitation Medicine, Kobe, Japan, 6Kobe University, Life and Medical Sciences Area, Health Sciences Discipline, Kobe, Japan
Background: Joint contractures are major complications of spinal cord injuries (SCI), and are characterized by limitations in the passive range of motion (ROM) of the affected joints. In clinical settings, BTX injection is effective for the treatment of spasticity, and is widely used in patients with contracture. However, the effect of BTX injection on muscles and periarticular structures have not been understood.
Purpose: Using an established rat model with SCI with knee flexion contractures, we aimed to verify whether the BTX injection affects structural changes in muscles and joint components responsible for contractures after SCI, and truly improves limitations of ROM in SCI.
Methods: Total 20 male Wistar rats, 10 weeks old, were randomly divided into 3 groups; a healthy group that had no intervention (control group), an untreated group with SCI (SCI group), and a BTX injections group after SCI (BTX group). We have reported previously that knee flexion contractures developed in rats with SCI for first 2 weeks postinjury. Therefore, in BTX group, the rats received BTX injections at 15th postoperative day of SCI. The rats at 2 and 4weeks after the injections were evaluated and compared with the age-matched animals in control group and SCI group. Knee extension motion was measured with a goniometer, and the muscular and articular factors responsible for contractures were calculated by measuring joint motion before and after the myotomies. We quantitatively measured the muscle atrophy, muscle fibrosis, and synovial intima length.
Results: All results showed a similar tendency, regardless of the duration of the intervention. The limitation in joint motion was developed after SCI. BTX injections significantly improved the limitation in motion. BTX injections were effective in improving the muscular factors, whereas there was little difference in the articular factors. SCI induced muscle atrophy and muscle fibrosis. BTX injections significantly accelerated muscle atrophy and muscle fibrosis. The synovial intima length decreased significantly after SCI, but BTX injections did not improve this shortening.
Conclusion(s): This animal study provides new evidence that BTX injections can improve limitations of ROM, but have adverse effects of muscle atrophy and fibrosis. In addition, BTX injections has no effect on articular factors.
Implications: Our study indicates that BTX may be less predictably true effective against contractures.
Keywords: Joint contracture, BTX injection, spinal cord injury
Funding acknowledgements: This study was supported by the Japan Society for the Promotion of Science (17K19908).
Purpose: Using an established rat model with SCI with knee flexion contractures, we aimed to verify whether the BTX injection affects structural changes in muscles and joint components responsible for contractures after SCI, and truly improves limitations of ROM in SCI.
Methods: Total 20 male Wistar rats, 10 weeks old, were randomly divided into 3 groups; a healthy group that had no intervention (control group), an untreated group with SCI (SCI group), and a BTX injections group after SCI (BTX group). We have reported previously that knee flexion contractures developed in rats with SCI for first 2 weeks postinjury. Therefore, in BTX group, the rats received BTX injections at 15th postoperative day of SCI. The rats at 2 and 4weeks after the injections were evaluated and compared with the age-matched animals in control group and SCI group. Knee extension motion was measured with a goniometer, and the muscular and articular factors responsible for contractures were calculated by measuring joint motion before and after the myotomies. We quantitatively measured the muscle atrophy, muscle fibrosis, and synovial intima length.
Results: All results showed a similar tendency, regardless of the duration of the intervention. The limitation in joint motion was developed after SCI. BTX injections significantly improved the limitation in motion. BTX injections were effective in improving the muscular factors, whereas there was little difference in the articular factors. SCI induced muscle atrophy and muscle fibrosis. BTX injections significantly accelerated muscle atrophy and muscle fibrosis. The synovial intima length decreased significantly after SCI, but BTX injections did not improve this shortening.
Conclusion(s): This animal study provides new evidence that BTX injections can improve limitations of ROM, but have adverse effects of muscle atrophy and fibrosis. In addition, BTX injections has no effect on articular factors.
Implications: Our study indicates that BTX may be less predictably true effective against contractures.
Keywords: Joint contracture, BTX injection, spinal cord injury
Funding acknowledgements: This study was supported by the Japan Society for the Promotion of Science (17K19908).
Topic: Neurology: spinal cord injury; Musculoskeletal: lower limb; Disability & rehabilitation
Ethics approval required: Yes
Institution: Kobe University
Ethics committee: Institutional Animal Care and Use Committee
Ethics number: P130408
All authors, affiliations and abstracts have been published as submitted.
