Objective

2

To observe the effects of electroacupuncture (EA) at "Jiaji" (EX-B 2) on extracellular matrix (ECM) of chondrocytes and inflammatory reaction in rabbits with Modic changes (MC) of cartilage endplate

and to explore the mechanism of EA in treating MC of endplate cartilage.

Methods

2

Eighteen male New Zealand white rabbits were randomly divided into a sham operation group

a model group and an EA group

6 rabbits in each group. Based on the autoimmune theory

MC model was established by embedding autogenous nucleus pulposus in the rabbits of the model group and the EA group

based on autoimmunity. After successful modeling

EA was applied at bilateral "Jiaji" (EX-B 2) of L

5

and L

6

in the EA group

with disperse-dense wave

2 Hz/15 Hz in frequency and 1 mA in current intensity

20 min a time

once a day

1-day interval was taken after continuous 6-day intervention

for 4 weeks totally. Before and after modeling

as well as before and after intervention

the comprehensive response score was observed. After modeling and intervention

magnetic resonance imaging (MRI) was used to observe the signal intensity of intervertebral disc and cartilage endplate. After intervention

the morphology of chondrocytes of cartilage endplate was observed by HE staining; the positive expression of a disintegrin and metalloproteinase with thrombospondin motif-5 (ADAMTS5) and Aggrecan in the cartilage endplate was detected by immunohistochemistry; the levels of inflammatory factors i.e

. interleukin-1β (1L-1β) and tumor necrosis factor-α (TNF-α) in the cartilage endplate were detected by ELISA; the protein expression of ADAMTS5

Aggrecan

matrix metalloproteinase-13 (MMP-13)

IL-1β and TNF-α in the cartilage endplate was detected by Western blot.

Results

2

Compared with the sham operation group

in the model group

the comprehensive response score was decreased (

P

<

0.01); L

5

/L

6

intervertebral disc and the cancellous bones of endplate vertebral body showed low signal and unclear boundary; the chondrocytes of the cartilage endplate increased significantly

the cells were enlarged and hypertrophic

and the nuclei were wrinkled and clustered; the positive expression of ADAMTS5 as well as the levels of IL-1β and TNF-α were increased (

P

<

0.01)

while the positive expression of Aggrecan was decreased (

P

<

0.01) in the cartilage endplate; the protein expression of ADAMTS5

MMP-13

IL-1β and TNF-α was increased (

P

<

0.01)

while that of Aggrecan was decreased (

P

<

0.01) in the cartilage endplate. Compared with the model group

in the EA group

the comprehensive response score was increased (

P

<

0.01); the signal of L

5

/L

6

intervertebral disc and the cancellous bones of endplate vertebral body was enhanced; the chondrocytes of the cartilage endplate were reduced

the nuclei were slightly crumpled and scattered; the positive expression of ADAMTS5 as well as the levels of IL-1β and TNF-α were decreased (

P

<

0.05

P

<

0.01)

while the positive expression of Aggrecan was increased (

P

<

0.01) in the cartilage endplate; the protein expression of ADAMTS5

MMP-13

IL-1β and TNF-α was decreased (

P

<

0.05

P

<

0.01)

while that of Aggrecan was increased (

P

<

0.05) in the cartilage endplate.

Conclusion

2

EA at "Jiaji" (EX-B 2) can delay the MC of cartilage endplate. The mechanism may be related to inhibiting the degradation of ECM of chondrocytes and the secretion of inflammatory factors

and repairing the degeneration of endplate cartilage.