establishment of a rat chronic constriction injury model

Improving FSN Therapy in the Rat Model&amp;#58; Minimizing Discomfort and Maximizing Efficiency

Neuropathic pain, defined as pain caused by nerve damage, is estimated to affect 6.9%-10% of the world&#39;s population, and the reported lifetime prevalence is 49%-70%1,2. It is also considered to be one of the most difficult pain syndromes to manage. The use of pharmacological agents to manage neuropathic pain has yielded limited success as commonly prescribed pain medications like non-steroidal anti-inflammatory drugs and opioids have shown little efficacy in relieving this type of pain3,4. There is therefore a great need to explore new treatment options, especially non-pharmacological treatments. Acupuncture, as a non-pharmacological intervention, potentially alleviate neuropathic pain by exerting analgesic effects on the somatosensory system. Both clinical and preclinical studies have indicated that acupuncture is effective in relieving neuropathic pain symptoms without significant side effects5,6,7. However, the central mechanism of acupuncture treatment for pain relief in neuropathic pain remains to be further investigated.
In recent years, Fu&#39;s subcutaneous needling (FSN) has gained popularity for treating pain-related neurological disorders8. FSN originated from traditional Chinese acupuncture and was first described by traditional Chinese physician Zhonghua Fu in 19969,10. While originating from traditional acupuncture, FSN differs significantly in its techniques and theories from meridian-based acupuncture, yin and yang principles, and acupuncture point concepts. FSN places greater emphasis on neurophysiological and anatomical approaches to effectively address myofascial pain11. FSN therapy is applied in clinical practice to address various painful muscular disorders, targeting the connective tissues closely associated with the muscles, particularly focusing on the treatment of tightened muscles (TMs)12. As a complementary therapy for pain relief, there is also clinical evidence that FSN is effective in treating soft tissue injuries in addition to providing rapid pain management and significant improvement in soft tissue spasms13,14. FSN therapy involves specific techniques tailored to address the underlying myofascial trigger points (MTrPs) associated with the condition. The FSN needle insertion position is carefully chosen based on the location of these trigger points, allowing precise targeting of affected areas. During the procedure, the FSN needle is inserted into the subcutaneous layer, where it is intentionally stopped to optimize therapeutic effects. A distinctive technique known as the swaying movement is then employed, involving a gentle oscillating motion of the needle to stimulate the tissues and promote the therapeutic responses10. The development of MTrPs is associated with the energy crisis theory, which explains that factors such as chronic muscle overload, excessive exercise, improper exertional postures, muscle atrophy, and degeneration can contribute to the onset of muscle tissue ischemia and hypoxia. This oxygen and energy deficiency within the muscle tissue is believed to play a key role in the formation of MTrPs15,16. Previous animal studies have found that FSN treatment for chronic pain in rats improves the morphological structure and function of mitochondria in TMs to some extent, validating the potential of FSN therapy to promote the recovery of damaged nerves and muscles17.
Sciatica has been classified as neuropathic pain18. The origin of neuropathic pain is thought to lie anywhere between the motor endplate and the outer fibrous layer of the muscle, involving the microvascular system and neurotransmitters at the cellular level. Loss of muscle innervation and apoptosis of innervated nerve cells occurs when nerve damage occurs19, leading to pain-related gait in the affected limb. Additionally, chronic compression or irritation of the nerve can lead to a variety of changes in the way of nerve functions, which can further exacerbate the symptoms of sciatica20. However, the complexity of the nervous system makes it difficult to replicate it in vitro, thus necessitating the use of animal models for such studies. In the investigation of neuropathic pain disorders, model organisms are commonly employed, involving various methods of direct peripheral nerve injury, such as sciatic nerve ligature, transection, or compression21,22. The chronic constriction injury (CCI) model in Sprague-Dawley rats has been used to induce neuropathic pain. This model replicates the pain induced by nerve injury observed in humans through surgical constriction of a peripheral nerve, mimicking the compression or entrapment seen in conditions such as nerve compression syndromes and peripheral neuropathies.
In this study, we evaluated the analgesic effects of FSN therapy and low-frequency electrotherapy (transcutaneous electrical nerve stimulator, TENS) in rats with chronic constriction injury and neuropathic pain. As anesthesia slows or blocks nerve impulses and affects synaptic transmission and neuronal function23, animals cannot be anesthetized under all needling procedures and swaying movements. Therefore, an appropriate needle technique is required to reduce discomfort in rats. The steps for establishing a rat CCI model, the way the rats were treated with FSN combined swaying movement without anesthesia, feasible animal behavioral pattern tests, and electrophysiological investigations are described in detail.

Author Spotlight: Unveiling the Therapeutic Effects of FSN Treatment &amp;#8211; Bridging Research and Clinical Applications in Neuropathic Pain

Efficacy of Fu's Subcutaneous Needling on Sciatic Nerve Pain: Behavioral and Electrophysiological Changes in a Chronic Constriction Injury Rat Model

1 This research investigates the analgesic effect<v>2 of Fu's subcutaneous needling therapy 3 and low-frequency electrotherapy in rats 4 with chronic constriction injury and neuropathic pain. 5 It explores nonpharmacological treatment options 6 for neuropathic pain 7 and examines the potential of FSN therapy 8 as an effective intervention. 9 The current experimental challenges include<v>10 developing appropriate needle techniques 11 to reduce discomfortable in rats 12 during Fu's subcutaneous needling therapy, 13 conducting needling procedures 14 and swaying movements without anesthesia, 15 establishing a reliable 16 and reproducible clinical constraint injury model in rats, 17 and accurately assessing behavior patterns 18 and electrophysiologic responses in neuropathic pain models.19 The significant finding from this study include<v>20 demonstrating the therapeutic effect of FSN treatment 21 on nerve pain in rat chronic constriction injury models, 22 and presenting a protocol 23 for evaluating the therapeutic effect using SFI 24 and the electrophysiological testing 25 after FSN intense treatment. 26 The findings of this study will advance research<v>27 in the field by providing a protocol 28 for evaluating FSN treatment, bridging basic research 29 and clinical application, improving patients'outcomes, 30 and enhancing understanding of disease mechanisms 31 for more effective treatments in neuropathic pain. 32 In the future, our laboratory aims<v>33 to incorporate immunohistochemistry 34 and morphological variation 35 to validate the effectiveness 36 of Fu's subcutaneous needling therapy 37 in nerve compression-related disease.38 We strive to deepen our understanding 39 of Fu's subcutaneous needling therapy, 40 contribute to pain management 41 and advance rehabilitation strategies.

Establishment of a Rat Chronic Constriction Injury Model

1 Begin by wearing a surgical mask, 2 disposable operating cap, and sterile gloves. 3 Clean the surgical table surface with 70%ethanol, 4 an autoclave, instruments, gauze, staples and cotton swabs. 5 Position the anesthetized rat on the operating table, 6 then shave.Its right hind leg hair. 7 Now disinfect the skin with Povidone-Iodine solution 8 and 75%Ethanol three times. 9 Make a 20 to 50-millimeter parallel skin incision 10 about three to four-millimeters below the femur.11 Cut through the subcutaneous fat 12 and superficial fascia layers using surgical scissors, 13 and locate and expose the gluteus maximus 14 and biceps femoris. 15 Using blunt scissors, sever the connective tissue 16 between the superficial gluteus 17 and biceps femoris muscles. 18 With the help of a retractor, expose the sciatic nerve 19 by widening the gap between the two muscles.20 Pick the sciatic nerve with a microneedle 21 through a good light source, 22 ensuring not to alter nerve morphology. 23 Ligate the sciatic nerve twice 24 using 3-0 chromic gut ligatures, 25 positioning the ligature points 26 approximately one-millimeter apart between the two sutures. 27 Create a loose loop for each ligature 28 and grasp the ends of the ligature close to the loop.29 Close the muscle with 4-0 suture lines 30 and then suture the skin layer.

establishment-of-a-rat-chronic-constriction-injury-model

Research

JoVE Journal

Medicine

154 Views. 1 Begin by wearing a surgical mask, 2 disposable operating cap, and sterile gloves. 3 Clean the surgical table surface with 70%ethanol, 4 an autoclave, instruments, gauze, staples and cotton swabs. 5 Position the anesthetized rat on the operating table, 6 then shave.Its right hind leg hair. 7 Now disinfect the skin with Povidone-Iodine solution 8 and 75%Ethanol three times. 9 Make a 20 to 50-millimeter parallel skin incision 10 about three to four-millimeters below the femur.11 ...

Video: Establishment of a Rat Chronic Constriction Injury Model

Fu&#39;s subcutaneous needling (FSN), an invented acupuncture technique from traditional Chinese medicine, is used worldwide for pain relief. However, the mechanisms of action are still not fully understood. During FSN treatment, the FSN needle is inserted and retained in the subcutaneous tissues for a long duration with a swaying movement. However, challenges arise from maintaining a posture while manipulating FSN in animal models (e.g., rats) for researchers. Uncomfortable treatment can lead to fear and resistance to FSN needles, increasing the risk of injury and may even affect research data. Anesthesia may also affect the study results too. Hence, there is a need for strategies in FSN therapy on animals that minimize injury during the intervention. This study employs a chronic constriction injury model in Sprague-Dawley rats to induce neuropathic pain. This model replicates the pain induced by nerve injury observed in humans through surgical constriction of a peripheral nerve, mimicking the compression or entrapment seen in conditions such as nerve compression syndromes and peripheral neuropathies. We introduce an appropriate manipulation for easily inserting an FSN needle into the subcutaneous layer of the animal&#39;s body, including needle insertion and direction, needle retention, and swaying movement. Minimizing the rat&#39;s discomfort prevents the rat from being tense, which causes the muscle to contract and hinder the entry of the needle and improves the study efficiency.

We present a protocol for using Fu's subcutaneous needling in a chronic constriction injury model to induce sciatic nerve pain in rats.

Fu&#39;s subcutaneous needling (FSN), an invented acupuncture technique from traditional Chinese medicine, is used worldwide for pain relief. However, the ...

Administration of Fu&#39;s Subcutaneous Needling (FSN) Manipulation in a Chronic Constriction Injury Rat Model

1 Begin by securing the rat<v>2 from Fu's subcutaneous needling 3 or FSN treatment group in the rodent, restrained, 4 exposing the affected limb laterally. 5 Slowly and gradually extend the rat's hind limbs 6 until stretched tight without anesthesia. 7 Now, remove the protective sheath of the FSN needle.8 Insert the needle tip toward the tightened muscles 9 near the gluteus maximus muscle 10 on the lower back and rear, 11 position the needle flat entering the skin at a 12 15 degree angle. 13 Push it cautiously 14 and swiftly to avoid tension in the rat, 15 ensuring full insertion of the needle 16 and burying the soft tube under the skin. 17 Begin the swaying movement by smoothly 18 and softly fanning the FSN needle tip, using the thumb 19 as the fulcrum and keeping the index, middle, 20 and ring fingers aligned in a straight line.21 Hold the FSN needle between the middle finger 22 and thumb facing each other 23 and alternate the movement using the index 24 and ring fingers, upon completing the manipulation, 25 quickly withdraw the FSN needle. 26 The sciatic function index 27 or SFI in the chronic constriction injury, 28 FSN Group improved significantly 29 compared to the injury group alone. 30 The improvement was significant in the FSN group 31 relative to the transcutaneous electrical nerve stimulator 32 or TENS group.33 The SFI of the sham, FSN, and TENS groups 34 did not have any significant 35 difference from each other, 36 proving the safety of the treatment groups. 37 The amplitude of CMAP 38 and the latency peaks in the injury FSN treatment group 39 improved significantly compared to the injury group alone. 40 The CMAP and latency peaks 41 of the treatment groups did not differ 42 significantly from each other.43 The CMAP amplitudes, and latency 44 of all three groups were statistically similar.

Administration of Transcutaneous Electrical Nerve Stimulator (TENS) Manipulation in a Chronic Constriction Injury Rat Model

1 Begin by fixing the rat<v>2 from the transcutaneous electrical nerve stimulation, 3 or, TENS treatment group, in a rodent restraint, 4 exposing the affected limb laterally. 5 Administer a low-frequency electrical stimulation 6 with the electrode applied on the leg around the nerve, 7 and to the Zusanli and Sanyinjiao points 8 using the TENS device for 10 minutes. 9 The sciatic function index, or SFI, 10 in the injury with TENS group 11 improved significantly 12 compared to the injury group alone.13 The improvement was significant in the FSN group 14 relative to the TENS group. 15 The SFI of the Sham, FSN, and TENS groups 16 did not have any significant difference from each other, 17 proving the safety of the treatment groups. 18 Improved amplitude of CMAP 19 relative to the injury alone group was observed.20 Similar observations were observed 21 with the latency peak in the injury 22 with TENS treatment group. 23 The CMAP and latency peaks of the treatment groups 24 did not differ significantly from each other. 25 The CMAP amplitudes and latency of all three groups 26 were statistically similar.