Effect Of Electroacupuncture At "Zhongzheng" Point On The Repairing Function And MTOR, Desmin Expression Of Lumbo Fissure Injury Induced By BPVC In Rats

BackgroundThe normal function and structure of multifidus muscles which are located under the waist is important to sustain the stability of lumbar vertebra. The causes which can delay the activation of the multifidus muscles, obstacle the coordination function, injury the structure will influence the stability of the lumbar vertebra, which is closely related to the incidence of chronic low back pain. Acupuncture is an effective method to treat low back pain and widely applied in clinical, but there is no reports about treating chronic low back pain caused by the injury of multifidus muscle with acupuncture methods recently. There are so many studies to survey the effect of acupuncture for skeletal muscle injury, the mechanism is focus on that acupuncture can regulate the production of the correlated cytokine to accelerate the regeneration and repair of the injured skeletal muscle satellite cells. This trial on one hand was try to verify the model of low back pain caused by the injury of multifidus muscle from histomorphology and skeletal muscle ultrastructure, and on the other hand to observe and evaluate the effect of electro-acupuncture for the injury of multifidus muscle and part of the mechanism.Objective1. To analysis and evaluate the damage degree and recovery period of multifidus muscle of rats with intramuscular injection of 5% bupivacaine to the rats lumber multifidus muscles from histomorphology, skeletal muscle ultrastructure and the score of ultrastructure change of injured skeletal muscle.2. To observe the effect of electro-acupuncture on multifidus muscle injury by the expression of Desmin and mTOR of rats with bupivacaine induced multifidus muscle toxicity, and discuss the possible mechanism of muscle tissue repair with the effects of weizhong(BL40) and shenshu(BL23).Methods72 male Sprague-Dawley rats were randomly divided into blank group (BG, n=18), model group (MG, n=18), weizhong (BL40) electro-acupuncture group (WG, n=18) and shenshu(BL23) electro-acupuncture group (SG, n=18), each group then divided evenly into three time points(day4, day7 and day 14) and each time point has 6 samples. The rats were anesthetized with intramuscular 10% Chloral Hydrate (350mg/kg) solution, multifidus muscle(L4 and L5 sections, four points, 100μl/point) toxicity was established by injecting 0.5% bupivacaine hydrochloride on MG,WG and SG. The BG was not given any treatment. WG and LG accepted electro-acupuncture for day 4, day 7 or day 14 after modeling. The histomorphology and the ultrastructure change of skeletal muscle of the multifidus muscle of each rat were observed by HE were observed under optical microscope and skeletal muscle ultrastructure change under TEM at day 4, day 7 and day 14. Immunohistochemical method was used to observe Desmin and mTOR expressions of the rat’s damaged multifidus muscles at day 4, day 7 and day 14. Comparing the difference between the weizhong electro-acupuncture group and shenshu electro-acupuncture group, thus discussed the mechanism of effect of the repair process of weizhong (BL40) and shenshu (BL23) point electro-acupuncture on rats multifidus muscles injury with BPVC.Results1. BPVC injection can accurately reach the rats multifidus muscle and lead to the injury of the muscle. The obvious changes can be found in model group at day 4, day 7 and day 14 from histomorphology and the ultrastructure change of skeletal muscle of the damaged multifidus muscle. From the HE staining, the necrosis of the local multifidus muscle fiber, inflammatory cell infiltration, some macrophages can be seen at day 4 in model group; the structure and arrange of the myofibril, zones and lines were disordered or disappeared; the structure of mitochondria was abnormal and lysis or reduction of mitochondrial cristae can be seen at day 4 in model group; regeneration and repair of the myofibril, the boundary of myofibril, zones and lines were gradually clear and mitochondria was near normal which can be seen from the HE staining and TEM at day 7 and day 14 in model group, the injury was not fully regenerated at day 14.2. Local BPVC injection can lead the injury of the multifidus muscle of rat, the damage was reversible. From the score of the ultrastructure change of skeletal muscle of the damaged multifidus muscle, the score of BG was significantly higher than MG (p<0.01), the score of WG and SG were lower than MG (p<0.01) at day 4; the score of WG was lower than MG and SG at day 4,7 and 14 (p<0.01); the score of SG was lower than MG at day 14 (p<0.01).3. The effects of Electro-acupuncture at BL40 and BL23 on the expression of mTOR and Desmin after the rat’s multifidus muscle injury induced by the injection of BPVC. ①mTOR: the expression of mTOR in MG was higher than BG (p<0.05) at day 4; the expression in MG had a statistically significant difference compared with BG at day 7 and day 14 (p<0.01); There was significant difference in the comparison between WG, SG and MG at day 4, day 7 and day 14(p<0.01); there was no difference between WG and SG at day 4 (p>0.05); There was significant difference in the comparison between WG and SG at day 7 and 14 (p<0.01).② Desmin:the expression of Desmin in MG was higher than in BG at day 4 (p<0.05), there was significant difference between the two groups at day 7 and 14 (p<0.01); there was difference between SG and MG at day 14 (p<0.05); there was significant difference between WG and MG at day 4, day 7 and day 14 (p<0.01); there was significant difference between WG and SG at day 14(p<0.01).Conclusion1. Local injection of BPVC could establish the model of the rat’s lumbar multifidus muscle injury, the changes of histomorphology and the ultrastructure change at different time points were significantly obvious. Electro-acupuncture on BL23 and BL40 can accelerate the regeneration of skeletal muscle from histomorphology and the ultrastructure change, the effect of BL40 was more significant.2. Electro-acupuncture on BL23 and BL40 could promote the repair of tissue after multifidus muscle injury, which may be related to the change of the expression of Desmin and mTOR. Electro-acupuncture on BL23 and BL40 could advance the expression of mTOR, enlarging the skeletal muscle cell, increasing the mass of the skeletal muscle. The trend of the advance of Electro-acupuncture on BL40 was like a peak; whereas the trend of BL23 was steady rising (falling).Both electro-acupuncture on BL23 and BL40 could promote the repair of process of skeletal muscle injury, but the effect of BL40 was wide and obvious; the time that BL 23 playing a role is later than BL40.