Objective

2

To assess the impacts of electroacupuncture (EA) on the gait

oxidative stress

inflammatory reaction

and protein degradation in the rats of denervated skeletal muscle atrophy

and explore the potential mechanism of EA for alleviating denervated skeletal muscle atrophy.

Methods

2

Forty male SD rats

8 weeks old

were randomly assigned to a sham-surgery group

a model group

an EA group

and a p38 MAPK inhibitor group

with 10 rats in each group. The right sciatic nerve was transected to establish a rat model of denervated skeletal muscle atrophy in the model group

the EA group and the p38 MAPK inhibitor group. In the sham-surgery group

the nerve was exposed without transection. One day after successful modeling

the rats in the EA group received EA at "Huantiao" (GB30) and "Zusanli" (ST36) on the right side

using a continuous wave with a frequency of 2 Hz and current intensity of 1 mA

for 15 min in each session

EA was delivered once a day

6 times a week. In the p38 MAPK inhibitor group

the rats received the intraperitoneal injection with SB203580 (5 mg/kg)

once a day

6 times a week. The intervention was composed of 3 weeks in each group. After the intervention completion

the CatWalk XT 10.6 animal gait analysis system was used to record the gait parameters of rats. The wet weight ratio of the gastrocnemius muscle was calculated after the sample collected. Using HE staining

the fiber morphology and cross-sectional area of the gastrocnemius muscle were observed; ELISA was employed to measure the content of interleukin (IL)-6

IL-1β

and tumor necrosis factor (TNF)-α in the gastrocnemius muscle; the biochemical hydroxyamine method was adopted to detect the content of superoxide dismutase (SOD) and malondialdehyde (MDA) in the gastrocnemius muscle; with immunohistochemistry and Western blot used

the expression of p38 mitogen-activated protein kinase (p38 MAPK)

phosphorylated (p)-p38 MAPK

muscle atrophy F-box gene (Atrogin-1)

muscle RING finger 1 (Murf-1)

nuclear factor E2-related factor 2 (Nrf2)

and heme oxygenase-1 (HO-1) was detected in the gastrocnemius muscle.

Results

2

Compared to the sham-surgery group

in the model group

the standing duration

the swing time and the step cycle were increased (

P

<

0.001)

the footprint area of the maximum contact time

the print area

the average intensity of the maximum contact time

the average intensity

the swing speed

and the step length were decreased (

P

<

0.001); the wet weight ratio of gastrocnemius muscle and fiber cross-sectional area were reduced (

P

<

0.001); the content of IL-6

IL-1β

TNF-α and MDA in gastrocnemius muscle elevated (

P

<

0.001)

and that of SOD reduced (

P

<

0.001); the positive and protein expression of p-p38 MAPK

Atrogin-1 and Murf-1 elevated (

P

<

0.001) and that of Nrf2 and HO-1 dropped (

P

<

0.001). When compared with t

he model group

in the EA group and the p38 MAPK inhibitor group

the standing duration

the swing time and the step cycle decreased (

P

<

0.01)

the footprint area of the maximum contact time

the print area

the average intensity of the maximum contact time

the average intensity

the swing speed

and the step length increased (

P

<

0.01); the wet weight ratio of gastrocnemius muscle and fiber cross-sectional area were improved (

P

<

0.01

P

<

0.05); the content of IL-6

IL-1β

TNF-α and MDA in gastrocnemius muscle dropped (

P

<

0.05

P

<

0.01)

and that of SOD elevated (

P

<

0.01

P

<

0.05); the positive and protein expression of p-p38 MAPK

Atrogin-1 and Murf-1 dropped (

P

<

0.01

P

<

0.05) and that of Nrf2 and HO-1 increased (

P

<

0.01

P

<

0.05).

Conclusion

2

Electroacupuncture may alleviate skeletal muscle atrophy in denervated skeletal muscle atrophy rats by mediating the p38 MAPK activity

thereby suppressing oxidative stress

inflammatory reaction

and protein degradation.