Exploring the mechanism of "three manipulations and three acupoints" tuina in improving motor function in rats with sciatic nerve injury through the neuromuscular signal conduction pathway

To observe the effects of "three manipulations and three acupoints" tuina on the recovery of motor function in rats with sciatic nerve injury, and to explore its mechanism.

Twenty-four male SD rats were randomly divided into four groups using a random number table method: normal, sham operation, model, and tuina groups, with six rats per group. The normal group received no intervention, whereas only the sciatic nerve was exposed in the sham operation group. In the model and tuina groups, the sciatic nerve was clamped and injured to create a rat model of sciatic nerve injury, simulating peripheral nerve injury in clinical settings. The normal group was not intervened. On the seventh day after modeling, the sham operation and model groups were given grip restraint; in the tuina group, a tuina manipulation simulator was used to apply an intervention involving "three manipulations and three acupoints," and the point-pressing, kneading, and plucking methods were applied on "Yinmen" (BL37), "Chengshan" (BL57), and "Yanglingquan" (GB34) in turn. The rats were rested for one day after 10 days of intervention, and the total intervention time was 20 days. Before modeling and after intervention, a grip strength test system was used to measure the grip strength of the hind limbs. After intervention, an automated gait analysis system was used to assess the gait of rats (walking duration, maximum contact area, and swing phase duration), and the sciatic function index (SFI) was calculated; a biological signal acquisition and analysis system was used to determine the sciatic nerve conduction velocity and surface electromyography (sEMG) signals (amplitude and incubation period) of the gastrocnemius muscle; the morphology, number, and area of motor endplate (MEP) at the neuromuscular junction (NMJ) of the gastrocnemius muscle were examined using the cupric ferrocyanide method; the concentrations of acetylcholine (ACh) and acetylcholinesterase (AChE) at the NMJ of the gastrocnemius muscle were detected using an enzyme-linked immunosorbent assay.

Compared with the normal and sham operation groups, the model group showed a decrease in hind limb grip strength (P<0.05); compared with the model groups, the tuina group exhibited an increase in hind limb grip strength (P<0.05). Compared with the normal and sham operation groups, the model group showed reductions in walking duration, maximum contact area, SFI, and gastrocnemius muscle sEMG amplitude (P<0.05); compared with the model group, the tuina group demonstrated increases in these indicators (P<0.05). Compared with the normal and sham operation groups, the model group showed increases in swing phase duration and gastrocnemius muscle sEMG incubation period (P<0.05); compared with the model group, the tuina group showed decreases in these indicators (P<0.05). Compared with the normal and sham operation groups, the model group showed lighter MEP staining, along with decreases in MEP number and area at the NMJ of the gastrocnemius muscle (P<0.05); compared with the model group, the tuina group exhibited darker MEP staining, as well as increases in MEP number and area (P<0.05). Compared with the normal and sham operation groups, the model group had lower concentrations of ACh and AChE at the NMJ of the gastrocnemius muscle (P<0.05); compared with the model group, the tuina group showed higher levels of these biomarkers (P<0.05).

Tuina can improve motor function in rats with sciatic nerve injury. Its mechanism may involve enhancing the efficiency of electrical signal conduction, increasing the sensitivity of chemical signal transmission at the NMJ, promoting nerve repair and regeneration, and modulating the reinnervation of muscles by nerves.