Objective

2

To observe the effect of electroacupuncture (EA) at "Zusanli" (ST36) on amyotrophic lateral sclerosis (ALS) in mouse models based on myeloid cell trigger receptor 2 (TREM2)-mediated microglial activation.

Methods

2

Thirty-six SPF-grade male human mutant superoxide dismutase 1 (SOD1-G93A) transgenic mice were divided into a model group

an EA group

and a drug group

12 mice in each group. Besides

12 wide-type littermates were collected as a control group. In the EA group

EA was performed at the "Zusanli" (ST36)

with an intermittent wave

at the frequency of 15 Hz

and for 10 min each intervention; once every other day

3 interventions a week and for 4 continuous weeks. In the drug group

the intragastric administration of riluzole solution was given at 8 mg/kg

once daily

for 4 continuous weeks. After intervention completion

behavioral assessment of mice was conducted using rotarod test and wire hang test. With HE and Nissl staining adopted

morphology of motor neurons in the anterior horn of the spinal cord was observed. Immunofluorescence was used to detect the fluorescence intensity of TREM2 in the anterior horn of spinal cord. Western blot analysis was performed to measure the protein expression of interleukin (IL)-1β

γ interferon (IFN-γ)

IL-4 and IL-10 in spinal cord tissue. Flow cytometry was used to analyze the proportion of CD86

+

and CD206

+

in spinal cord monocyte suspension.

Results

2

Compared with the control group

in the model group

motor neurons in the anterior horn of the spinal cord exhibited disordered arrangement; accompanied by nuclear pyknosis

and cytoplasmic shrinkage; the latency to fall in the rotarod test and the cut-off time in the wire hang test were shortened

fluorescence intensity of TREM2 in the spinal anterior horn

the protein expression of IL-1β

IFN-γ

IL-4

and IL-10

and the proportion of CD86

+

and CD206

+

in spinal cord tissue increased(

P

<

0.01). When compared with the model group

in the EA and drug groups

motor neurons in the anterior horn of the spinal cord were arranged regularly; nuclear pyknosis and chromatolysis were attenuated

and the structural integrity of neurons was improved; the latency to fall and the the cut-off time were prolonged

fluorescence intensity of TREM2 in the spinal anterior horn was reduced

the protein expression of IL-1β and IFN-γ decreased

and that of IL-4

and IL-10 increased in the spinal cord tissue; the proportion of CD86

+

in spinal cord tissue was reduced and that of CD206

+

elevated(

P

<

0.01

P

<

0.05). Compared with the drug group

the EA group showed the increase of protein expression of IL-1β

and the decrease of IL-4

IL-10 in the spinal cord tissue and the proportion of CD206

+

(

P

<

0.05).

Conclusion

2

Electroacupuncture at "Zusanli" (ST36) exhibits a certain improvements in motor function of SOD1-G93A transgenic mice. The underlying mechanism may be related to attenuating neuroinflammation via the modulation of microglial activation mediated by TREM2.