Experimental Study on Mechanical Vibration Massage for Treatment of Brachial Plexus Injury in Rats

Objective: To investigate the curative effect of the self-made mechanical vibration massage instrument for treatment of brachial plexus injury in rats and to explore its mechanism. Methods: Brachial plexus injury models were made in 144 Wistar rats and one week after natural healing of the wound, they were randomly divided into 3 groups, mechanical vibration treatment group (MV group), nerve growth factor treatment group (NGF group) and model group, 48 rats in each group. Then again, the each group was randomly divided into 4 subgroups, 7-day group, 14-day group, 21-day group and 28-day group, 12 rats in each subgroup. The MV group were treated by mechanical vibration at acupoints on three-yang and three-yin channels of the hand with the mechanical vibration massage instrument; The NGF group were treated with injection of NGF into musculus pectoralis major on the affected side; And the model group were normally fed with no treatment. After treatment for 7, 14, 21 and 28 days, the diameter of both forelimbs were measured, the electrophysiological examination on the brachial plexus in vitro and the ultrastructure observation with electron microscope on the affected side were carried out, the motor nerve conduction velocity (MNCV) and motor nerve action potential (MNAP) of the brachial plexus on the affected side, NGF content of submaxillary gland as well as muscular Na(+), K(+)-ATPase activity were determined respectively. Results: The different rates of the forelimb diameter in the MV group and the NGV group on the 14th d, 21st d and 28th d were better than those in the model group (P<0.05 or P<0.001), and in the MV group were better than those in the NGF group on the 21st d and the 28th d (P<0.05). MNCV in the MV group and the NGV group on the 21st d and 28th d was better than that in the model group (P<0.05 or P<0.001), and in the MV group was better than that in the NGF group on the 28th d (P<0.05). MNAP in the MV group and the NGV group on the 14th d, 21st d and 28th d was better than that in the model group (P<0.05 or P<0.001), and in the MV group was better than that in the NGF group on the 21st d and 28th d (P<0.05). The NGF mean gray index of submaxillary gland in the model group was higher than that in the MV group and the NGF group on the 7th d (P<0.05); in the NGF group and the model group was higher than that in the MV group on the 14th d (P<0.05); and in the NGF group and the MV group was higher than that in the model group on the 21st d and 28th d (P<0.05). Na(+), K(+)-ATPase activity in the model group and the MV group was higher than that in the NGF group (P<0.05) on the 14th d, and in the MV group was higher than that in the model group on the 28th d (P<0.05). Conclusion: As compared with the NGF group and the model group, mechanical vibration treatment can effectively accelerate repair of injured brachial plexus, slow down atrophy of skeletal muscle, and promote secretion of NGF in submaxillary gland.