1.Effect of Tuina at "Weizhong (BL 40)" on Spinal Microglial Activation-related Proteins and the IL-10/β-EP Pathway in a Rat Model of Chronic Sciatic Nerve Compression Injury
Tianwei ZHANG ; Xiangqian LYU ; Yani XING ; Liuchen ZHU ; Qingguang ZHU ; Lingjun KONG ; Yanbin CHENG ; Zhen YAN ; Wuquan SUN ; Min FANG ; Zhiwei WU
Journal of Traditional Chinese Medicine 2025;66(7):734-740
ObjectiveTo investigate the analgesic effect of Tuina at the "Weizhong (BL 40)" on neuropathic pain in a rat model of chronic constriction injury (CCI) of the sciatic nerve and its potential central spinal mechanisms. MethodsThirty-two Sprague-Dawley rats were randomly divided into four groups (8 rats in each group), sham-operated group, model group, Tuina group, and blockade group. The CCI model was established in the model group, Tuina group, and the blockade group by ligating the sciatic nerve with catgut, while the sham-operated group underwent only sciatic nerve exposure without ligation. From postoperative day 4 to day 14, rats in the Tuina group and the blockade group received Tuina manipulation at the "Weizhong (BL 40)" using a dynamic pressure distribution measurement system (5 N pressure, 2 Hz frequency, 10 min per session, once daily). The blockade group also received intraperitoneal injections of the microglial inhibitor minocycline (10 mg/kg) once daily. The sham-operated and the model group underwent the same handling and fixation as the Tuina group without actual Tuina. Mechanical withdrawal threshold (MWT) and paw withdrawal latency (PWL) were measured before surgery and on day 3, 7, 10, and 14 post-surgery. Transmission electron microscopy was used to evaluate sciatic nerve injury and repair, measuring axon diameter and total myelinated fiber diameter to calculate the g-ratio. Western Blotting was performed to detect the protein levels of ionized calcium-binding adapter molecule 1 (Iba-1), CD206, CD68, interleukin-10 (IL-10), and β-endorphin (β-EP) precursor pro-opiomelanocortin (POMC) in the ipsilateral spinal dorsal horn. ResultsCompared with the sham-operated group, the model group showed significantly reduced MWT and PWL on day 3, 7, 10, and 14 (P<0.01). Compared with the model group, the Tuina group and the blockade group showed increased MWT and PWL on day 10 and 14 (P<0.05). Compared with the Tuina group, the blockade group exhibited higher MWT on day 7, 10, and 14, and higher PWL on day 10 (P<0.05). Sciatic nerve pathological morphology revealed intact and well-structured myelin in the sham-operated group, while the model group exhibited myelin collapse, distortion, and myelin ovoid formation. The Tuina group displayed partially irregular myelin with occasional myelin collapse, whereas the blockade group exhibited partial myelin irregularities and phospholipid shedding. Compared with the sham-operated group, the model group showed a decreased g-ratio and increased levels of Iba-1 and CD68 in the spinal dorsal horn (P<0.05 or P<0.01). Compared with the model group, the Tuina group and the blockade group exhibited an increased g-ratio and reduced Iba-1 and CD68 levels. Additionally, the Tuina group showed elevated levels of CD206, IL-10, and POMC, whereas the blockade group had decreased CD206 levels (P<0.05). ConclusionTuina at "Weizhong (BL 40)" alleviates neuropathic pain in CCI rats, potentially by regulating microglial activation in the spinal cord, inhibiting M1 polarization while promoting M2 polarization, and activating the IL-10/β-EP pathway to exert analgesic effects.