Introduction
Extracorporeal shock wave therapy (ESWT) has been widely used in various clinical and experimental models for the treatment of painful conditions such as epicondylitis, plantar fascitis and also bone and wound healing. There is evidence that ESWT improves the metabolic activity of various cell types, (e.g. chondrocytes and endothelial cells) but little is known about its effects on nervous tissue. The injection of safe doses of botulinum neurotoxin A (BoNT/A) have been reported to be useful for the treatment of neuropathic pain, but it is still unknown how functional recovery is induced after peripheral nerve injury. The aim of this study is to investigate whether ESWT or BoNT/A improves the regeneration of injured nerves in an experimental rat model.
Methods
After sciatic nerve crush, intranerve delivery of BoNT/A or ESWT were applied, axonal regeneration was measured by gait analysis, electrophysiologic studies and morphological investigations at different days.
Two experimental groups were set up: the group 1 animals received intranerve delivery of BoNT/A(15pg) whereas group 2 animals received ESWT (400 impulses,4 Hz) immediately after nerve injury. A group 3(control group) received only nerve injury. The survival time was 3weeks.
Regeneration of myelinated fibers was assessed by immunofluorescence and western blot. The antibodies used were GFAP, GAP43, NF200, ATF3, S100.
Results
We observed a higher expression of S100 in the distal portion of BoNT/A-injected or ESWT received regenerated nerves 3 weeks after nerve injury. With respect to axonal regeneration, antibodies expressions in the experimental groups were also significantly higher than those in the control group. During 3 weeks’ clinical observation following BoNT/A or ESWs application, functional improvement of the hindlimb was observed without clinical deterioration by trials.
All antibodies used in the experiment were expressed with a statistically significant increase in the BoNT/A injection and ESWT groups compared to the control group.
A series of nerve conduction studies were conducted. When the mean of the first and third week amplitudes of the 5 rats in each group were compared, the amplitude increased by 2.64 times in the ESWT group. The amplitude was improved by 1.54 times in the BoNT/A injection group, and 1.18 times in the control group.
When comparing the first and third week of the Sciatic nerve Functional Index (SFI) results, ESWT group showed the greatest improvement +49.93 from -57.86 to -8.926. Secondly, the control group improved by +37.09, and the BoNT/A injection group showed a +31.00 improvement
CONCLUSIONS
Both the BoNT/A injection group and the ESWT group had an effect on nerve regeneration, but the ESWT group was more effective than the BoNT/A group. In addition, the ESWT group showed a relatively normal gait pattern than the BoNT/A injection group and the control group, so this is considered to be helpful for functional improvement.
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