Title : Mechanism of electro acupuncture to alleviate TRPV1 overexpression in chronic pain in the ascending pain pathway
Abstract:
TRPV1 (transient receptor potential vanilloid 1) is a nonselective cation channel that has been associated with the initiation of inflammatory pain. Previously, numerous mouse studies demonstrated the impact of TRPV1 on acute and inflammatory pain. This experiment, however, illustrates that TRPV1 had an impact on chronic neuropathic pain, which is defined to persist for more than three months in humans. Furthermore, the ICD-11 classifies chronic pain as a primary condition that requires different treatment than the pain caused by other conditions. Asa result, this experiment was motivated by a desire to study about the underlying mechanism of pain signaling to the central nervous system. Pain signals are transmitted through many important brain regions, particularly the thalamus, hippocampus, and somatosensory cortex, in second-order and third-order neurons. Acupuncture treatment is a thousands-year-old traditional medicine technique whose effects remain being investigated. Electroacupuncture is an acupuncture technique that incorporates electrical stimulation, with low-frequency EA (2Hz) having a stronger analgesic effect than high-frequency EA (100 Hz). Evidence showed that EA at 2 Hz at acupoint ST36 decreased neuropathic pain after 1 hour by depressing the C-long-term fiber (LTD). According to ancient documents, acupuncture manipulation causes numbness, pain, fullness, and heaviness in inpatient at the acupoint, while the acupuncturist feels tense, tight, and full like a fish biting a hook or the qi sensation comes like a bird flying, this is referred to as de-qi. The intermittent cold stress pain model in mice was used in our experiment to mimic chronic pain. After 2 weeks, the diseased mice in the CSP group (cold stress pain) had a dramatic reduction in the mechanical and thermal pain thresholds, whereas the 2Hz EAapplied mice also had an alteration after electroacupuncture, the pain threshold was reduced significantly. After one week of EA treatment, the response threshold of the EA group was gradually increased to a normal level. The mice in the Sham EA group, on the other hand, did not alter this. For comparison, we included the TRPV1 knock-out group, which then had no reduction in pain threshold when persistent pain was also induced. To better understand the molecular mechanism, we performed a western-blot experiment to look for upstream molecules like TRPV1 and downstream molecules like MAPK. The results showed that the percentage of TRPV1 was overexpressed in the CSP group, but there was a significant decrease in the 2Hz EA group. However, this reduction effect was not present in the Sham EA group, and the percentage of TRPV1 expression was significantly decreased in the TRPV1 knock-out group. In this experiment, we discovered a relation between brain structures and the presence of proteins that occur after chronic pain induction. Low-frequency electroacupuncture has been observed to be successful at inhibiting these pain-related proteins, establishing acupuncture as a potential treatment for chronic pain, and revealing the mechanism of chronic pain relief via TRPV1
