Electroacupuncture alleviates cerebral ischemia injury by promoting microglial polarization and inhibiting inflammation in MCAO rats.

BACKGROUND

Electroacupuncture (EA), a Chinese traditional medicine, has a protective effect on cerebral ischemic injury. However, the mechanism underlying its effect is still unclear. In this study, we assessed whether EA can promote microglia polarization and inhibit inflammation, thereby protecting against cerebral ischemic injury in ischemic stroke rats.

METHODS

Male Sprague-Dawley (SD) rats were randomly divided into five groups, including the sham group, the middle cerebral artery occlusion (MCAO) group, the EA group, the EA+normal saline (NS) group, and the EA + lipopolysaccharide (LPS) group. Behavior and cerebral edema were evaluated with a five-point neurological deficit scale and the wet/dry method. The degree of brain injury in the rats was observed via Nissl and TUNEL staining. The expression levels of proteins related to M1/M2 polarization and the inflammatory response were determined via western blotting and immunofluorescence staining.

RESULTS

The motor abilities of the EA and EA+NS group rats were significantly greater than those of the MCAO group rats. Ischemic damage occurred in MCAO rats, with significantly increased TUNEL and iNOS/Iba1, and enhanced expression of TNF-α, IL-6, and IL-1β in the MCAO group rats. Compared with the MCAO group, the Nissl and CD163/Iba1 fluorescence intensities of the EA and EA+NS groups were higher, whereas TUNEL and iNOS/Iba1 fluorescence intensities were lower, and the expression levels of inflammatory factors decreased. Compared with those in the EA and EA+ NS groups, the TUNEL and iNOS/Iba1 fluorescence intensities in the EA+LPS group were increased, as well as the expression of IL-6.

CONCLUSIONS

EA may promote M1/M2-type polarization, regulate the neuroinflammatory response, and alleviate neurological dysfunction in MCAO rats. Furthermore, the overall infection condition can affect the therapeutic effect of EA.