Objective:

2

To investigate the effect of Chinese herbal formula Ermiao Powder (二妙散

EMP) on the expression of cholinergic anti-inflammatory pathway in rats with rheumatoid arthritis (RA).

Methods:

2

Seventytwo rats were randomly divided into 6 groups according to body weight

including normal control group

collageninduced arthritis (CIA) group

three doses EMP groups

and methotrexate (MTX) group (

n

=12 per group). All of the rats except for those in the normal control group were given multipoint subcutaneous injection of bovine type Ⅱ collagen to establish a CIA model. Three EMP groups received a high- (4.5 g/kg)

medium- (3.0 g/kg)

and low- (1.5 g/kg) doses of EMP by intragavage

respectively. MTX group was injected intraperitoneally MTX at 0.9 mg/kg once a week as the positive control. The administration was 3 consecutive weeks. Joint swelling

arthritis index

and body weight changes in different experimental groups of rats were tested. The joint damage was evaluated by masson staining. Quantitative real-time polymerase chain reaction

Western blot

and immunohistochemistry (IHC) were performed to evaluate the expression of CHRNA7

encoding α7 nicotinic acetylcholine receptor in the cholinergic anti-inflammatory pathway

in different tissues and their localization in the spleen and joints.

Results:

2

CHRNA7 expression levels were significantly higher in the joints and spleens of CIA group than those in normal control group (both

P

<

0.05). Moreover

the CHRNA7 mRNA and protein levels in the spleen and joints of MTX and three doses of EMP groups were significantly lower than CIA group (all

P

<

0.05). Compared with the MTX group

treatment with low-dose EMP resulted in significant reduction of CHRNA7 mRNA and protein expression levels (

P

<

0.05 or

P

<

0.01). IHC showed positive signals of CHRNA7 in the white pulp and red pulp of the spleens of rats; CHRNA7 was expressed on fibroblast-like synoviocytes

macrophages

and endothelial cells in the joints of rats

and the expression in the joints of low-dose EMP group was significantly lower than that in the CIA group (

P

<

0.01).

Conclusion:

2

Cholinergic anti-inflammatory pathway was involved in the generation of the inflammatory reaction in CIA rats

and EMP exerted therapeutic effect on RA through cholinergic anti-inflammatory pathway.