Objective

2

To explore the central mechanism of the short-needling method for treating knee osteoarthritis (KOA) based on electroencephalogram (EEG) signals.

Methods

2

Thirty-one KOA patients were recruited as the KOA group

and 31 age-

sex-

and BMI-matched healthy subjects were recruited as the healthy group. The KOA group received "short-needling" therapy at Neixiyan (EX-LE5)

Dubi (ST35)

Yinlingquan (SP9)

Zusanli (ST36)

and Liangqiu (ST34) on the affected side

once daily

6 consecutive days as a treatment course

with a 1-day break between treatment courses

for a total of 4 treatment courses. Western Ontario and McMaster Universities osteoarthritis index (WOMAC) score was assessed before and after treatment; the levels of inflammatory cytokines (interleukin-1β [IL-1β] and tumor necrosis factor-α [TNF-α]) in synovial fluid were measured; the relative power of resting-state EEG signals (Delta

Theta

Alpha

Beta

Gamma frequency bands) and EEG network topological indexes (global clustering coefficient

global efficiency

mean degree

and network density) were analyzed in KOA patients before and after treatment and in healthy subjects.

Results

2

(1) Compared before treatment

the KOA group showed significantly reduced WOMAC scores in joint pain

stiffness

physical function

and total scores after treatment (

P

<

0.001); IL-1β and TNF-α levels in synovial fluid were also significantly reduced (

P

<

0.001). (2) In the Theta band

compared before treatment

the relative power in 10 brain regions was decreased significantly after treatment in the KOA group (

P

<

0.05

P

<

0.01); except for the prefrontal cortex

the relative power in other regions of the KOA group remained higher than the healthy group before treatment (

P

<

0.01). In the Beta band

compared before treatment

the relative power in all regions except the prefrontal cortex increased after treatment in the KOA group (

P

<

0.05

P

<

0.01); before treatment

KOA patients had lower relative power in the left/right frontal lobes

left/right parietal

central parietal region

left/right temporal

and occipital lobes compared to the healthy group (

P

<

0.01). (3) Compared with the healthy group

the KOA group showed abnormally enhanced functional connectivity in Theta

and Gamma bands in the prefrontal cortex before treatment; after treatment

this abnormal connectivity was attenuated. (4) Compared before treatment

the global clustering coefficient

mean degree

and global efficiency in the Theta band networks of the prefrontal cortex decreased significantly after treatment (

P

<

0.05)

approaching levels of the healthy group (

P

>

0.05); all four topological metrics before treatment in the KOA group were significantly higher than those in the healthy group (

P

<

0.01). (5) The relative Theta power in the left frontal lobe was positively correlated with the difference in WOMAC score before and after treatment (

P

<

0.05); the relative Gamma power in the right frontal lobe was negatively correlated with the difference in WOMAC score before and after treatment (

P

<

0.05).

Conclusion

2

The short-needling method could effectively improve joint function in KOA patients

reduce slow-wave Delta activity

increase fast-wave Beta activity

and regulate abnormally enhanced brain functional connectivity networks. These EEG changes are correlated with WOMAC score.