ABSTRACT
Objective To observe the effect of the electroacupuncture ( EA) on the expression of cyclin-de-pendent kinase 5 ( Cdk5 ) in rats with muscle contusion and to explore its mechanism. Methods Thirty-two Sprague-Dawley rats were randomly divided into a normal group of 4, a model group of 4, a natural recovery group ( NR) of 12 and an EA group of 12. All except those in the normal group had acute skeletal muscle contusion induced through a heavy blow. The EA group was treated with 15 minutes of EA daily beginning 48 h after the injury while the other rats received no EA. The model group was sacrificed 24 h after modeling, and rats from the NR and EA groups were sacrificed on the 7th, 14th and 21st day after the modeling to collect tissues. Hematoxylin eosin ( HE) staining, Western blotting and quantitative real-time fluorescence PCR were used to observe any histological changes, as well as Cdk5 protein and mRNA expression. Results The HE staining showed that the other 3 groups displayed larger a-mounts of muscle fiber fracture, dissolution and inflammatory cell invasion than was observed in the normal group. Compared with the NR group, quicker recovery was seen in the EA group as evidenced by faster muscle satellite cell proliferation and more new muscle fiber generation. The average Cdk5 protein expression in both the NR and EA groups was higher than in the normal group, and that of the EA group was significantly lower than that of the NR group. Conclusions Muscle contusion can increase Cdk5 expression in skeletal muscles, at least in rats. EA can promote the restoration of skeletal muscle function, probably by inhibiting CDK5 protein and mRNA expression.
ABSTRACT
@#Objective To observe effects and mechanism of electroacupuncture (EA) on denervated skeletal muscle atrophy. Methods Forty-nine male Sprague-Dawley rats were randomly divided into normal group (group A, n=7), natural recovery group (group B, n=21) and EA group (group C, n=21). The groups B and C, established the model of denervated skeletal muscle atrophy by transecting the sciatic nerve of rats, were divided into subgroups of 7 days, 14 days, 21 days postoperation, seven in each subgroup. Electroacupuncture was given to the group C at Zusanli (ST36) and Chengshan (BL57) once a day since 24 hours after modeling. The muscle wet weight ratio of the affected gastrocnemius was determined. Cross-sectional area and fiber diameter of the gastrocnemius were measured with HE staining. The expression of insulin-like growth factor-1 (IGF-1), Myostatin and proliferating cell nuclear antigen (PCNA) protein and gene in the gastrocnemius were detected with Western blotting and RT-PCR. Results The wet weight ratio, cross-sectional area and fiber diameter were less in the groups B and C than in the group A (P<0.001), and they were more in the group C than in the group B (P<0.001). Compared with the group B, the protein and gene of IGF-1, PCNA increased in the group C (P<0.05), while the Myostatin decreased (P<0.05). Conclusion Electroacupuncture can increase the expression of IGF-1 and decrease the expression of Myostatin, to promote the proliferation of satellite cell, which may relate with the prevention of denervated skeletal muscle atrophy.