Electric stimulation and decimeter wave therapy improve the recovery of injured sciatic nerves

Evaluation of peripheral nerve injury according to the severity of damage using 18F-FDG PET/MRI in a rat Model of sciatic nerve injury

OBJECTIVES

We ascertained that the PET scan may be a valuable imaging modality for the noninvasive, objective diagnosis of neuropathic pain caused by peripheral nerve injury through the previous study. This study aimed to assess peripheral nerve damage according to severity using18F-FDG PET/MRI of the rat sciatic nerve.

METHODS

Eighteen rats were divided into three groups: 30-second (G1), 2-minute (G2), and 5-minute (G3) crushing injuries. The severity of nerve damage was measured in the third week after the crushing injury using three methods: the paw withdrawal threshold test (RevWT), standardized uptake values on PET (SUVR), and intensity analysis on immunohistochemistry (IntR).

RESULTS

There were significant differences between G1 and G3 in both SUVR and IntR (p = 0.012 and 0.029, respectively), and no significant differences in RevWT among the three groups (p = 0.438). There was a significant difference in SUVR (p = 0.012), but no significant difference in IntR between G1 and G2 (p = 0.202). There was no significant difference between G2 and G3 in SUVR and IntR (p = 0.810 and 0.544, respectively).

DISCUSSION

Although PET did not show results consistent with those of immunohistochemistry in all respects, this study demonstrated that PET uptake tended to increase with severe nerve damage. If this research is supplemented by further experiments, PET/MRI can be used as an effective diagnostic modality.

Application and underlying mechanism of acupuncture for the nerve repair after peripheral nerve injury: remodeling of nerve system

Peripheral nerve injury (PNI) is a structural event with harmful consequences worldwide. Due to the limited intrinsic regenerative capacity of the peripheral nerve in adults, neural restoration after PNI is difficult. Neurological remodeling has a crucial effect on the repair of the form and function during the regeneration of the peripheral nerve after the peripheral nerve is injured. Several studies have demonstrated that acupuncture is effective for PNI-induced neurologic deficits, and the potential mechanisms responsible for its effects involve the nervous system remodeling in the process of nerve repair. Moreover, acupuncture promotes neural regeneration and axon sprouting by activating related neurotrophins retrograde transport, such as nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), glial cell-derived neurotrophic factor (GDNF), N-cadherin, and MicroRNAs. Peripheral nerve injury enhances the perceptual response of the central nervous system to pain, causing central sensitization and accelerating neuronal cell apoptosis. Together with this, the remodeling of synaptic transmission function would worsen pain discomfort. Neuroimaging studies have shown remodeling changes in both gray and white matter after peripheral nerve injury. Acupuncture not only reverses the poor remodeling of the nervous system but also stimulates the release of neurotrophic substances such as nerve growth factors in the nervous system to ameliorate pain and promote the regeneration and repair of nerve fibers. In conclusion, the neurological remodeling at the peripheral and central levels in the process of acupuncture treatment accelerates nerve regeneration and repair. These findings provide novel insights enabling the clinical application of acupuncture in the treatment of PNI.

Role of shortwave and microwave diathermy in peripheral neuropathy

Objective

This study was performed to review the current evidence for the efficacy of shortwave and microwave diathermy in promoting nerve regeneration after peripheral nerve injuries in both animal models and human patients.

Methods

An extensive literature search was conducted without publication data restrictions. Studies including the intervention and outcome in animal or human models were selected. Non-English studies, reviews, letters, and case reports were excluded.

Results

Eleven articles were included in this study. Shortwave diathermy at the frequency of 27.12 or 40.68 MHz was used in six of seven animal studies, while only one study utilized microwave diathermy at 915 MHz. Seven animal experiments demonstrated that shortwave or microwave diathermy produces an increased myelinated nerve fiber number, myelin sheath thickness, and axon diameter as well as improved electrophysiological parameters and locomotion. A total of 128 patients (207 wrists) were enrolled in four clinical studies. The clinical use of diathermy in human patients with carpal tunnel syndrome showed positive effects on pain, hand function, and electrophysiological findings.

Conclusions

Shortwave or microwave diathermy can improve the electrophysiological parameters, myelinated fiber number, and axon diameter of the injured nerve.

Electroacupuncture and moxibustion promote regeneration of injured sciatic nerve through Schwann cell proliferation and nerve growth factor secretion

Using electroacupuncture and moxibustion to treat peripheral nerve injury is highly efficient with low side effects. However, the electroacupuncture- and moxibustion-based mechanisms underlying nerve repair are still unclear. Here, in vivo and in vitro experiments uncovered one mechanism through which electroacupuncture and moxibustion affect regeneration after peripheral nerve injury. We first established rat models of sciatic nerve injury using neurotomy. Rats were treated with electroacupuncture or moxibustion at acupoints Huantiao (GB30) and Zusanli (ST36). Each treatment lasted 15 minutes, and treatments were given six times a week for 4 consecutive weeks. Behavioral testing was used to determine the sciatic functional index. We used electrophysiological detection to measure sciatic nerve conduction velocity and performed hematoxylin-eosin staining to determine any changes in the gastrocnemius muscle. We used immunohistochemistry to observe changes in the expression of S100—a specific marker for Schwann cells—and an enzyme-linked immunosorbent assay to detect serum level of nerve growth factor. Results showed that compared with the model-only group, sciatic functional index, recovery rate of conduction velocity, diameter recovery of the gastrocnemius muscle fibers, number of S100-immunoreactive cells, and level of nerve growth factor were greater in the electroacupuncture and moxibustion groups. The efficacy did not differ between treatment groups. The serum from treated rats was collected and used to stimulate Schwann cells cultured in vitro. Results showed that the viability of Schwann cells was much higher in the treatment groups than in the model group at 3 and 5 days after treatment. These findings indicate that electroacupuncture and moxibustion promoted nerve regeneration and functional recovery; its mechanism might be associated with the enhancement of Schwann cell proliferation and upregulation of nerve growth factor.

Biological conduit small gap sleeve bridging method for peripheral nerve injury: regeneration law of nerve fibers in the conduit

The clinical effects of 2-mm small gap sleeve bridging of the biological conduit to repair peripheral nerve injury are better than in the traditional epineurium suture, so it is possible to replace the epineurium suture in the treatment of peripheral nerve injury. This study sought to identify the regeneration law of nerve fibers in the biological conduit. A nerve regeneration chamber was constructed in models of sciatic nerve injury using 2-mm small gap sleeve bridging of a biodegradable biological conduit. The results showed that the biological conduit had good histocompatibility. Tissue and cell apoptosis in the conduit apparently lessened, and regenerating nerve fibers were common. The degeneration regeneration law of Schwann cells and axons in the conduit was quite different from that in traditional epineurium suture. During the prime period for nerve fiber regeneration (2-8 weeks), the number of Schwann cells and nerve fibers was higher in both proximal and distal ends, and the effects of the small gap sleeve bridging method were better than those of the traditional epineurium suture. The above results provide an objective and reliable theoretical basis for the clinical application of the biological conduit small gap sleeve bridging method to repair peripheral nerve injury.