To Investigate The Impact Of Skeletal Muscle Injury And Repair Electrical Based BFGF / ERK Signaling Pathway

Objective:To observe the effects and discuss the mechanism of electro-acupuncture’s function of repairing skeletal muscle injury based on bFGF/ERK signal passway. Methods:Part Ⅰ:The observation of a-shi point electro-acupuncture’s early recovery and regeneration effects on rats’gastrocnemius muscle damage and bFGF expression. Rat model of gastrocnemius muscle damage was set up by cumulative contusion combined with treadmill exercise. The morphological changes and PCNA, Desmin, bFGF expressions of the gastroncnemius muscle were observed at the first,4th, and7th day after the application of electro-acupuncture on a-shi point for the evaluation and mechanism study of a-shi point electro-acupuncture’s effects on the proliferation and differentiation rate of rats’muscular satellite cells after gastrocnemius muscle injury.Part Ⅱ:Effects ot weizhong (BL40) and a-shi point electro-acupuncture on rabbits’acute lumbar muscle contusion and bFGF/ERK pass-way. Experiment in part Ⅱ applied dynamic observation of weizhong (BL40) and a-shi point electro-acupuncture’s regulatory effects on rabbits’ serum CK activity at the first,4th,7th, and14th day. Taking rabbits’ average lumbar muscle cell number, cross section area of the muscle fiber, nuclei number per fiber, thickness of grade I perimysium, and histomorphological changes at the14th day into consideration, the study compared and analyzed the differences between electro-acupuncture on weizhong (BL40) and a-shi point. It also discussed the mechanism of the regenerative effects of weizhong (BL40) and a-shi point electro-acupuncture on rabbit’s acute lumbar muscle contusion by observing changes of lumbar muscle PCNA, Desmin, ERK1/2, and bFGF in blood serum and spinal cord at the14th day.Part Ⅲ:A-shi point electro-acupuncture’s effects on muscle recovery and regeneration of acute lumbar muscle contusion rabbits and bFGF/ERK pass-way of rabbits administrated with U0126. The study applied dynamic observation of weizhong (BL40) and a-shi point electro-acupuncture’s regulatory effects on rabbits’ serum CK activity at the1th,14th day, after ERK inhibitor, U0126, had been administrated. It also combined rabbits’average lumbar muscle cell number, cross section area of the muscle fiber, nuclei number per fiber, thickness of grade I perimysium, and histomorphological changes with expression changes of PCNA, Desmin, ERK1/2, and bFGF in rabbits’lumbar muscle for the further discovery of bFGF/ERK pass-way’s mediation of a-shi point electro-acupuncture’s regenerative effects on rabbits’lumbar muscle contusion.Results:1. A-shi point electro-acupuncture’s early regenerative effects on rats’ gastrocnemius muscle injury. Results of histomorphological test showed that, at the4th day after injury, rats in the electro-acupuncture group were of relieved inflammatory cell infiltration of the gastrocnemius muscle and comparatively massive muscular cell regeneration. At the7th day, rats in the electro-acupuncture group were of lower connective tissue proliferation rate and histomorphological score, compared with that of the model group (p<0.01). Rats in the electro-acupuncture group were of significantly higher gastrocnemius Desmin and bFGF one day after the injury, compared with that of the model group (p<0.01, p<0.05). At the4th day, gastrocnemius PCNA, Desmin, and bFGF of the electro-acupuncture group were remarkably higher than that of the model group (p<0.05, p<0.01, p<0.01).2. Effects of Weizhong (BL40) and a-shi point electro-acupuncture on acute lumbar muscle contusion rabbits’muscle regeneration and bFGF/ERK pass-way in recovery phase. Histopathological sections showed that,14days after the injury, rabbits in the model group were of disarranged muscle fiber, remarkably increased proliferation of connective tissue, and decreased muscular cell regeneration. Rats in we thong (BL40) electro-acupuncture group were of comparatively bigger muscular cells, low proliferation of connective tissue, with regeneration and fusion of muscular cells observed. In a-shi point electro-acupuncture group, more regenerated muscular cells can be observed, with low proliferation of connective tissue. Rabbits in the model group were of drastically decreased muscular cell number, average cross sectional area of muscle fiber (CSA), nuclei number per fiber(NPF)(p<0.05, p<0.01, p<0.01), and significantly higher histomorphological score and thickness of grade I perimysium (p<0.01, p<0.05), compared with that of the blank control group. Among the indices, CSA and NPF were also significantly lower than that in weizhong (BL40) electro-acupuncture group (p<0.05, p<0.05) and a-shi point electro-acupuncture group (p<0.05, p<0.05). The histomorphological score and thickness of grade I perimysium were remarkably higher than that in the weizhong (BL40) electro-acupuncture group (p<0.01, p<0.05) and a-shi point electro-acupuncture group (p<0.01, p<0.05). Histomorphological score of weizhong (BL40) electro-acupuncture group is remarkably lower than that of a-shi point electro-acupuncture group (p<0.05). One day after the injury, serum CK concentrations of the model group, weizhong (BL40) electro-acupuncture group, and a-shi point electro-acupuncture group were significantly higher than that of the blank control group (p<0.01). The index of the model group was significantly lower than that of the weizhong (BL40) electro-acupuncture group and a-shi point electro-acupuncture group (p<0.01, p<0.05) at the4th day after the injury, and rose again to a level remarkably higher than the blank control group (p<0.01) at the7th day. While serum CK contents of weizhong (BL40) electro-acupuncture group was significantly lower than that of the model group (p<0.01) and a-shi point electro-acupuncture group (p<0.05), with that of the a-shi point electro-acupuncture group greatly lower than the model group (p<0.05). At the14th day after the injury, serum CK of the model group was significantly higher than that of the blank control group (p<0.05), while that of the weizhong (BL40) electro-acupuncture group and a-shi point electro-acupuncture group reduced to a level remarkably lower than the model group (p<0.01, p<0.01). At the14th day after the injury, lumbar muscle PCNA, ERK1/2, and bFGF expressions of rabbits in the model group were significantly higher than that in the blank control group (p<0.01, p<0.05, p<0.01). And its PCNA, Desmin, ERK1/2, and bFGF expressions were remarkably lower than that of weizhong (BL40) electro-acupuncture group (p<0.05, p<0.05, p<0.05, p<0.01) and a-shi point electro-acupuncture group (p<0.01, p<0.05, p<0.05, p<0.01). Lumbar muscle PCNA and bFGF expressions of weizhong (BL40) electro-acupuncture group were remarkably lower than a-shi point electro-acupuncture group (p<0.05, p<0.01). And bFGF in lumbar spinal cord of rabbits in the model group was greatly higher than that of the blank control group (p<0.01), but significantly lower than weizhong (BL40) electro-acupuncture group (p<0.01). At the4th day after the injury, serum bFGF of the model group was remarkably higher than that of the blank control group (p<0.01), weizhong (BL40) electro-acupuncture group (p<0.05), and a-shi point electro-acupuncture group (p<0.05). But there’s no significant difference of the index between all the groups at the7th day. At the14th day, serum bFGF of the model group was significantly lower than that of the blank control group. The same index of a-shi point electro-acupuncture group was greatly lower than that of the model group (p<0.01) and weizhong (BL40) electro-acupuncture group.3. Effects of a-shi point electro-acupuncture on U0126-intervened acute lumbar muscle contusion rabbits’muscle regeneration and bFGF/ERK signal pass-way. At the14th day after the injury, histopathological sections of the model group showed disarranged muscle fiber, obviously proliferated connective tissue, and less regenerated muscle cells. U0126-intervened model group were of obviously decreased and shrunk muscular cells, and less regenerated connective tissue. Rabbits in the electro-acupuncture group were of orderly arranged muscle fiber, more regenerated muscular cells, and slightly proliferation of connective tissue. Rabbits of the U0126-intervened electro-acupuncture group had a small amount of connective tissue proliferation and comparatively severe proliferation of connective tissue. The histomorphological score of the model group was significantly higher than that of the blank control group (p<0.01, p<0.01), and greatly lower than that of the U0126-intervened model group (p<0.01). The score of electro-acupuncture group was remarkably lower than that of the model group (p<0.01) and U0126-intervened electro-acupuncture group (p<0.01). The number of muscular cells, CSA, and NPF of the model group were greatly lower than that of the blank control group (p<0.05, p<0.01, p<0.01), but higher than U0126-intervened model group (p>0.05, p<0.01, p<0.05). The indices of electro-acupuncture groups were higher than that of the model group (p>0.05, p<0.05, p<0.05) and U0126-intervened electro-acupuncture group (p>0.05, p<0.05, p<0.01). Thickness of grade I perimysium of the model group was significantly higher than that of the blank control group (p<0.01) and U0126-intervened model group (p<0.05). The same index of the electro-acupuncture group was lower than that of the model group (p<0.05), but had no significant difference with U0126-intervened electro-acupuncture group (p>0.05). Serum CK content of the model group was remarkably higher than that of the blank control group (p<0.01), and had no significant difference with U0126-intervened model group (p>0.05). The index of the electro-acupuncture group was greatly lower than that of the model group (p<0.05) and U0126-intervened electro-acupuncture group (p<0.05).14days after the injury, lumbar muscle PCNA, ERK1/2, and bFGF of rabbits in the model group were significantly higher than that of the blank control group (p<0.01, p<0.01, p<0.05). Expressions of PCNA, Desmin, and ERK1/2of rabbits in the U0126-intervened model group was remarkably lower than that of the model group (p<0.01, p<0.01, p<0.01). PCNA, Desmin, ERK1/2, and bFGF expressions of rabbits in the electro-acupuncture group were greatly higher than the model group (p<0.01, p<0.05, p<0.05, p<0.01). PCNA, Desmin, and ERK1/2expressions of rabbits in U0126-intervened electro-acupuncture group were lower than that of the electro-acupuncture group (p<0.05, p<0.01, p<0.01).Conclusion:1.A-shi point electro-acupuncture can boost the proliferation and differentiation of satellite cells of gastrocnemius muscle damaged rats. The mechanism may lies in the up-regulation of bFGF expression.2. Electro-acupuncture on weizhong (BL40) point and a-shi can both boost proliferation and differentiation of satellite cells, and regenerative repair of the tissue in recovery stage of acute lumbar muscle contusion rabbits. The mechanism may concerns regulation of bFGF contents in local tissue, blood serum, and spinal cord. ERK1/2pass-way may be one of the important pass-ways mediating curative the effects of electro-acupuncture.3. Effect on weizhong (BL40) of promoting repairmen is batter than a-shi point, and there may be differences between the action pass-ways of a-shi point electro-acupuncture and weizhong (BL40) electro-acupuncture. Weizhong (BL40) electro-acupuncture works mainly by general regulation of the nerve-endocrine network. It is thereby of morc obvious effect on bFGF release in the spinal cord. The details of the two mechanisms are to be further studied. On the contrary, A-shi point electro-acupuncture works mainly by pulling stimulation, which had more obviously regulatory effects on bFGF in local tissue.4. The application of ERK inhibitor, U0126, can partly block a-shi point electro-acupuncture’s effects of stimulating proliferation and differentiation of satellite cells and regenerating muscles on acute lumbar muscle contusion rabbits. bFGF/ERK signal pass-way may be one of the important ways for muscle recovery and regeneration of a-shi point electro-acupuncture.