Acupuncture improves the structure of spastic muscle and decreases spasticity by enhancing GABA, KCC2, and GABAAγ2 in the brainstem in rats after ischemic stroke.

Background: Increasing data show that structural changes of spastic muscle and hyperexcitability of reticulospinal tract (RST) are involved in the pathogenesis of spasticity after stroke (SAS). Our previous study has indicated that the anti-spastic effect of acupuncture, especially waggle needling (WN, a multiple directional needling method with joint movement), on SAS rats was related to the KCC2-GABAA pathway in cerebral cortex. Furthermore, as a peripheral stimulation to treat upper motor neuron injury-related spasticity, acupuncture's effect on peripheral spastic muscles and inhibitory neurotransmitters in the brainstem, the origin of the RST, should be further clarified. This study aimed to examine the effect of acupuncture on the structure of spastic muscle and on the KCC2-GABAA pathway in the brainstem of SAS rats.

Methods: Middle cerebral artery occlusion (MCAO) or a sham operation were conducted in SD rats to establish SAS and control models. Behavioral assays, muscle myosin ATPase staining, and molecular biology technologies were used to compare different groups.

Results: In SAS models, hindlimb motor ability was decreased, neurologic deficits and spasticity were induced, the proportion of type I muscle fibers in spastic muscle was increased, and the expressions of γ-aminobutyric acid (GABA), KCC2, and the GABAAγ2 subunit of the pentameric GABAA receptor in the brainstem were decreased. Acupuncture including WN and perpendicular needling (PN) reversed these effects of MCAO. Furthermore, the therapeutic effect of WN was better than that of PN.

Conclusions: Acupuncture after MCAO improves the structure of spastic muscle and decreases spasticity probably at least partly by enhancing GABA, KCC2, and GABAAγ2 in the brainstem in SAS rats.