Zhongguo quanke yixue (Dec 2023)
Effect and Mechanism of Pivot Meridian Massage on TLR8/ERK Signaling Pathway and LncRNA-GAS5 in Rats with Neuropathic Pain
Abstract
Background Pivotal meridian massage for neuropathic pain obtained favorable results in recent years, however, its specific mechanism of action has not been fully elucidated. Objective To observe the analgesic effect of pivotal meridian massage on rats according to the research indexes taking rat model of neuropathic pain induced by L5 spinal nerve ligation as the object of observation, to further investigate whether the analgesic effect is achieved by affecting LncRNA-GAS5 and then regulating the apoptosis of neurons in the dorsal horn of the spinal cord. Methods The experiment was conducted from January to June 2021 at the Experimental Center for Animal Medicine of Guangxi University of Chinese Medicine and Guangxi University. A total of 120 healthy female SD rats were randomly divided into the normal group, model group, sham-operated group, sham-manipulation group, and meridian manipulation group, with 24 rats in each group. Rat model of neuropathic pain was prepared by ligating the L5 spinal nerve in the model, sham-operated, sham-manipulation and meridian manipulation groups. After modeling for 24 hours, the L5 spinal nerve was exposed for a few minutes without ligation, and the wound was closed layer by layer in the sham-operated group; hind limbs of the rats in the sham-manipulation group were gently stroked for 18 minutes; a self-made massager was used to sequentially stimulate the three acupoints on the bilateral Foot Shaoyang Gallbladder Meridian of Huan Tiao, Yang Ling Quan, and Xuan Zhong, with a stimulation force of 5 N, frequency of 2 Hz, intervention of 1 minute for each acupoint and technique, totaling 18 minutes in the meridian manipulation group. The normal group and model group were fed and observed normally without any intervention. Behavioral tests (mechanical withdrawal threshold and thermal withdrawal latency) were performed before modeling and on days 1, 3, 7, and 14 after modeling. On days 7 and 14 of the intervention, 12 rats were randomly selected for tissue sampling to detect the expression of TLR8/ERK signaling pathway-related proteins (Bcl-2, Caspase-3, ERK, TLR8 protein levels) and the expression levels of LncRNA-GAS5 and miR-21 genes in the spinal cord tissue. Results (1) In terms of behavioral observations, the mechanical withdrawal threshold of the model group, sham-manipulation group, and meridian manipulation group was lower than the normal group on days 1, 3, 7, and 14 after modeling (P<0.05) . The mechanical withdrawal threshold of the sham-operated group, sham-manipulation group and meridian manipulation group was higher than the model group on day 14 after modeling (P<0.05) . The mechanical withdrawal threshold of the sham-operated group, meridian manipulation group was higher than the sham-manipulation group on days 7 and 14 after modeling (P<0.05) . The thermal withdrawal latency in the sham-manipulation group and meridian manipulation group was shorter than the normal group on days 1, 3, and 7 after modeling (P<0.05) . The thermal withdrawal latency in the sham-operated group, sham-manipulation group and meridian manipulation group was longer than the model group on days 7 and 14 after modeling (P<0.05) . The sham-operated group, meridian manipulation group had longer thermal withdrawal latency than the sham-manipulation group on day 14 after modeling (P<0.05) . (2) In terms of protein and gene expression levels related to the signaling pathway, on day 7 after modeling, the Bcl-2 protein expression level in the normal group was lower than the other groups (P<0.05) . The Bcl-2 protein expression level in the meridian manipulation group was higher than the model group, while the Caspase-3, ERK, and TLR8 protein expression levels were lower than the model group (P<0.05) . The Bcl-2, Caspase-3, ERK, and TLR8 protein expression levels in the meridian manipulation group were lower than the sham-operated group, sham-manipulation group (P<0.05) . On day 14 after modeling, the Bcl-2 protein expression level in the meridian manipulation group remained higher than the model group, while the Caspase-3 and TLR8 protein expression levels remained lower than the model group, and the ERK protein expression level was higher than the model group (P<0.05) . After 7 days of modeling, the expression level of LncRNA-GAS5 gene in the sham-manipulation group and meridian manipulation group was higher than the model group, while the expression level of miR-21 gene was lower than the model group (P<0.05) . The expression level of LncRNA-GAS5 gene in the meridian manipulation group was higher than the sham-manipulation group, while the expression level of miR-21 gene was lower than the sham-manipulation group (P<0.05) . After 14 days of modeling, the expression level of LncRNA-GAS5 gene in the model group was lower than the normal group, while the expression level of LncRNA-GAS5 gene in the meridian manipulation group and sham-manipulation group was higher than the model group (P<0.05) . The expression level of miR-21 gene in the meridian manipulation group and sham-manipulation group was higher than the model group (P<0.05) . Conclusion The meridian manipulation technique has a certain analgesic effect on rats with neuropathic pain. It is initially hypothesized that the analgesic mechanism may be achieved by upregulating the expression level of LncRNA-GAS5 to inhibit neuronal apoptosis by adsorbing miR-21 to mediate TLR8/ERK pathway-related proteins. Although the specific mechanism has not been conclusively confirmed, LncRNA-GAS5 is expected to be a new target for future treatment of neuropathic pain in the future.
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