ABSTRACT
Objective:To investigate the effects and mechanism of Tuina on denervation-induced atrophy. Methods:A total of 42 Sprague-Dawley rats were randomly divided into sham group (n = 6), model group (n = 18) and Tuina group (n = 18). The model group and Tuina group freed and excised right tibia nerve about one centimeter, while the sham group freed the right tibia nerve only. From the second day after operation, Tuina group accepted Tuina on the injured area, while the sham group and the model group were only fixed without any intervention. Six rats were sacrificed on the 14th, 21st and 28th day after operation in the model and Tuina groups, and the sham group was sacrificed on the 28th day after operation. The gastrocnemius muscles were measured wet weight ratio. The diameter and area of muscle cells were measured under HE staining. The expression of Pax7, MyoD, MyoG, microRNA-1, microRNA-133a and microRNA-206 in the gastrocnemius muscles were detected with reverse transcription real-time quantitative polymerase chain reaction. Results:Compared with the sham group, the wet weight ratio, the area of muscle cells (except the 14-day-Tuina group) and the diameter of muscle cells decreased at each time point in the model group and Tuina group (P < 0.05); compared with the model group, the wet weight ratio, muscle cell diameter and muscle cell area increased at each time point in Tuina group (P < 0.05). Compared with the sham group, the expression of Pax7 increased in the 14-day-model group (P < 0.05) and decreased in the 28-day-model group (P < 0.05), and it increased at each time point (except 28-day) in Tuina group (P < 0.05); compared with the model group, the expression of Pax7 increased at each time point in Tuina group (P < 0.05). Compared with the sham group, the expression of MyoD and MyoG increased at each time point in the model group and Tuina group (P < 0.05); compared with the model group, the expression of MyoD and MyoG increased at each time point (except 14-day) in Tuina group (P < 0.05). Compared with the sham group, the expression of microRNA-1 and microRNA-133a decreased, and microRNA-206 increased in the model group and Tuina group at 21-day (P < 0.05); compared with the model group, the expression of microRNA-1, microRNA-133a and microRNA-206 increased in Tuina group (P < 0.05). Conclusion:Tuina may activate the Pax7/MyoD/MyoG pathway by increasing the expression of muscle-specific microRNA, to promote the proliferation and differentiation of muscle satellite cells, and delay denervation-induced atrophy.
ABSTRACT
Muscle loses normal function after skeletal muscle atrophy that will greatly reduce the quality of personal life. There is no effective way to treat muscle atrophy currently. microRNA (miRNA) as a small molecule of non-coding RNA brings new hope for the treatment of muscular atrophy. The mechanism of miRNA regulating muscle atrophy mainly includes: regulating abnormal muscle protein metabolism by ubiquitin-proteasome system (UPS) and mammalian target of rapamycin pathway (IGF/PI3K/Akt/mTOR), inhibiting abnormal apoptosis of muscle cells by inhibiting the expression of apoptotic factors, promoting muscle regeneration by regulating myogenic factor expression, and promoting angiogenesis by promoting the expression of angiogenic factors, and so on.
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Objective:To explore the effect and mechanism of Tuina on denervated skeletal muscle atrophy. Methods:A total of 77 male Sprague-Dawley rats were randomly divided into sham group (n = 7), model group (n = 35) and Tuina group (n = 35). The latter two groups were established skeletal muscle atrophy model by exposing and cutting off the common tibial nerve of rats. One day after modeling, the lower limbs of the surgical side received Tuina in Tuina group. Separately, the surgical side of gastrocnemius muscle were sampled on the 0th, 7th, 14th, 21st and 28thday after modeling, and measured the wet mass ratio. The cross-sectional area and diameter of muscle fiber were measured after HE staining. The mRNA expression of autophagy-realated factor Beclin-1, vacuolar protein sorting (Vps34) and microtubule-associated protein light chain 3 (LC3) were tested with reverse transcription real-time quantitative polymerase chain reaction. Results:There was no statistical difference in the ratio of gastrocnemius wet weight, the cross-sectional area and diameter of muscle fiber, and the mRNA expression of Beclin-1, Vps34 and LC3 among three groups on the 0th day (F < 1.321, P > 0.05). Compared with the sham group, the ratio of gastrocnemius wet weight, the cross-sectional area and diameter of muscle fiber decreased at different time points in the model group and Tuina group (P < 0.05), the ratio of gastrocnemius wet weight was higher, and the cross-sectional area and diameter of muscle fiber were bigger, both except on the 21st day, in Tuina group than in the model group (P < 0.05). Compared with the sham group, the mRNA expression of Beclin-1, Vps34 and LC3 increased at different points in the model group than in Tuina group (P < 0.05), and all the mRNA expression was higher, except on the 14th day, in Tuina group than in the model group (P < 0.05). The ratio of gastrocnemius wet weight, the cross-sectional area and diameter of muscle fiber showed a trend of progressive decrease with time in the model group and Tuina group (P < 0.05). The mRNA expression of Beclin-1 and Vps34 increased (P < 0.05), and the mRNA expression of LC3 increased in the model group 21 days after intervention (P < 0.05). The mRNA expression of Beclin-1, Vps34 and LC3 increased first and then decreased, except the mRNA expression on the 14th day in Tuina group (P < 0.05). Conclusion:Tuina may promote the activation of autophagy by up-regulating the expression of autophagy-realated factor Beclin-1, Vps34 and LC3, remove the damaged organelles and proteins, provide certain synthetic substrate and energy for muscle fiber regeneration, thereby reduce the loss of degree of denervated skeletal muscle atrophy.
ABSTRACT
OBJECTIVE@#To investigate the therapeutic effects of massage on denervated skeletal muscle atrophy in rats and its mechanism.@*METHODS@#Forty-eight male SD rats were randomly divided into model group (n=24) and massage group (n=24). Gastrocnemius muscle atrophy model was established by transecting the right tibial nerve of rat. On the second day after operation, the gastrocnemius muscle of the rats in the massage group was given manual intervention and the model group was not intervened. Six rats were sacrificed at the four time points of 0 d, 7 d, 14 d and 21 d. The gastrocnemius of the rats were obtained and measured the wet mass ratio after weighing. Cross-sectional area and diameter of the muscle fiber were measured after HE staining. The relative expressions of miR-23a, Akt, MuRF1 and MAFbx mRNA were tested with qPCR.@*RESULTS@#Compared with 0 d, the wet weight ratio, cross-sectional area and diameter of gastrocnemius muscle showed a progressive decline in the model group and massage group. The wet weight ratio, cross-sectional area and diameter of gastrocnemius muscle in the massage group were higher than those in the model group on 7 d, 14 d and 21 d (P＜0.05, P＜0.01). Compared with 0 d, the expressions of MuRF1, MAFbx and Akt mRNA were increased first and then were decreased in the model group and massage group. The expression of MuRF1 mRNA in massage group was lower than that in model group on 7 d and 21 d (P＜0.05, P＜0.01). The expression of MAFbx mRNA in massage group was lower than that in model group on 7 d, 14 d and 21 d (P＜0.01, P＜0.05, P＜0.01). The expression of Akt mRNA in massage group was higher than that in model group on 7 d, 14 d and 21 d (P＜0.05, P＜0.01). Compared with 0 d, the expression of miR-23a mRNA was increased in the model group and massage group on 21 d, and the expression of miR-23a mRNA in massage group was higher than that in model group (P＜ 0.05).@*CONCLUSION@#Massage can delay the atrophy of denervated skeletal muscle. The mechanism may be related to up-regulation of the expression of miR-23a and Akt mRNA, down-regulation of the expressions of MuRF1 and MAFbx mRNA, inhibition of protein degradation rate, and reduction of skeletal muscle protein degradation.