Objective

2

To observe the effect of acupuncture on chondrocyte autophagy in rats of knee osteoarthritis (KOA) and explore its underlying mechanisms.

Methods

2

Forty male SPF-grade SD rats were randomized into a blank group

a model group

a suspension group

an acupuncture group

and a combined therapy group

8 rats in each one. Except the blank group

KOA model was prepared by the injection with papain. The suspension exercise therapy (10 min each time

three times daily)

acupuncture (at "Yanglingquan" [GB34]

"Zusanli" [ST36]

and "Dubi" [ST35] on the right side

30 min each intervention

once daily) and the combined therapy (the suspension exercise therapy combined with acupuncture) were delivered in the suspension group

the acupuncture group and the combined therapy group

respectively. The intervention of each group was performed continuously for 6 days

and 4 consecutive weeks

at the interval of 1 day. Before and after intervention

Lequesne MG score was assessed in the rats. After intervention

HE staining was adopted to observe the cartilaginous tissue morphology of the right knee joints

and Mankin score was evaluated; the serum levels of interleukin (IL)-1β

IL-6

and tumor neurosis factor-α (TNF-α) were measured using ELISA; the real-time PCR was provided to determine the mRNA expression of collagen protein type Ⅱ(COL2)

collagen protein type Ⅹ (COL10)

phosphatidylinositol 3-kinase (PI3K)

protein kinase B (Akt)

mammalian target of rapamycin (mTOR)

and autophagy-regulated protein (Beclin-1) in the cartilaginous tissue of the right knee joint; Western blot was employed to detect the protein expression of PI3K

phosphorylated PI3K (p-PI3K)

Akt

phosphorylated Akt (p-Akt)

mTOR

phosphorylated mTOR (p-mTOR) and Beclin-1 in the cartilaginous tissue of the right knee joint.

Results

2

Compared with the blank group

the rats in the model group showed the higher Lequesne MG score (

P

<

0.01)

thinner cartilage of the right knee

reduced chondrocytes and disordered arrangement

and higher Mankin score (

P

<

0.01). Besides

in the model group

the serum levels of IL-1β

IL-6 and TNF-α were elevated (

P

<

0.01)

the mRNA expression of COL2 and Beclin-1 and the protein expression of Beclin-1 decreased (

P

<

0.01)

the mRNA expression of COL10

PI3K

Akt and mTOR

and the protein expression of p-PI3K

p-Akt and p-mTOR increased (

P

<

0.01) in the cartilaginous tissue of the right knee joint. Compared with the model group

in the suspension group

the acupuncture group and the combined therapy group

the Lequesne MG scores were reduced (

P

<

0.01)

the cartilage of the right knee was thickened

the arrangement of chondrocytes was improved

and the Mankin scores were lower (

P

<

0.01). Besides

in these intervention groups

the serum levels of IL-1β

IL-6 and TNF-α were reduced (

P

<

0.01)

the mRNA expression of COL2 and Beclin-1 and the protein expression of Beclin-1 increased (

P

<

0.05

P

<

0.01)

the mRNA expression of COL10

PI3K

Akt and mTOR

and the protein expre

ssion of p-PI3K

p-Akt and p-mTOR decreased (

P

<

0.05

P

<

0.01) in the cartilaginous tissue of the right knee joint. When compared with the suspension group and the acupuncture group

in the combined therapy group

the Lequesne MG score was reduced (

P

<

0.01)

and the Mankin score was reduced (

P

<

0.05

P

<

0.01). Besides

the serum levels of IL-1β

IL-6 and TNF-α were reduced (

P

<

0.05)

the mRNA expression of COL2 and Beclin-1 and the protein expression of Beclin-1 increased (

P

<

0.05)

the mRNA expression of COL10

PI3K

Akt and mTOR

and the protein expression of p-PI3K

p-Akt and p-mTOR decreased (

P

<

0.05

P

<

0.01) in the cartilaginous tissue of the right knee joint.

Conclusion

2

Acupuncture can promote cartilage regeneration of knee joint and autophagy in KOA rats

alleviate inflammation

so as to retard cartilage degeneration

which may be possibly associated with the PI3K/Akt/mTOR signaling pathway.