Rat Model for Rheumatoid Arthritis (RA)

Grab anesthetized rats and inject 0.1 ml Complete Freund's Adjuvant (CFA) on the right posterior foot intradermal to induce inflammation, so as to establish the model; the control group, inject 0.01 mol/L acetic acid 0.1 ml on the right toe subcutaneous, to the exclusion of the sensitized effect in CFA solvent.

Weight measurement:
record the weight of rats on 0d, 7d, 14d, 21d, 28d.
Organ index:
Weigh the rats and take the thymus and spleen, saline rinses with gauze to absorb the surface moisture, respectively to measure the weight (wet weight), and calculate the organ index.
Organ index=organ wet weight(mg) /body weight(g)
Plantar swelling value:
with electronic vernier caliper to measure rat paw thickness. Left and right lateral plantar control and group control were measured on every 7 days (7, 14, 21 and 28).
Arthritis index (AI):
Arthritis index score is used to evaluate the degree of inflammation. Score each foot claw, to 0 to 4 points in the record, cumulative score is the arthritis index of each mouse.
0 points: no erythema and swelling of the evidence;
1 points: erythema and mild swelling in the middle of the foot or ankle;
2 points: erythema and mild swelling from the ankle to the middle of the foot spread;
3 points: erythema and mild swelling from the ankle to the joint spread;
4 points: erythema and severe swelling, including the ankle, foot and toe.

The rats were sacrificed, specimens from the hind ankle joints, fixed, decalcified, embedded in paraffin, HE staining for histological observation. Rat in control group:ankle joint structure is normal, no inflammatory cell infiltration, synovial cells arranged in neat, smooth cartilage surface, no effusion in the joint cavity;
Rats in the model group were significantly damaged, surrounded with a large number of neutrophil infiltration, synovial hyperplasia, fibrous tissue hyperplasia, cartilage and bone damage.

Take 1mL blood from inferior vena cava and separate the serum. Assay immediately or store samples in aliquot at -80℃ for later use. Avoid repeated freeze/thaw cycles.
Using ELISA kit to assay the quantity of TNF alpha, IL-1 beta and other cytokines

SPSS software is used for statistical analysis, measurement data to mean ± standard deviation (x ±ｓ), using t test and single factor analysis of variance for group comparison , P<0.05 indicates there was a significant difference, P<0.01 indicates there are very significant differences.