Objective: To observe the effect of electrothermo-needle(ETN) treatment on Cyclooxygenase(COX)-2 mRNA expression osteosynovial cells in collagen-induced arthritis(CIA) rats.Methods: A total of 50 Wistar male rats(180-(200 g)) were randomized into normal control

model

higher electric current((40 mA)) ETN

low-current((20 mA)) ETN

no-current((0 mA)) ETN groups

with 10 cases in each group.Arthritis model was established by injecting type-Ⅱ collagen((100 μg)) into the rats' subcutaneous tissues of the bilateral hind-paws.ETN was applied to bilateral "Yanglingquan"(GB 34) once every other day with(20 min) each time and 20 times altogether.The rats' ankle-joint swelling degree(intensity of pressure) was detected by using joint volume detector.COX-2 mRNA expression of osteosynovial cells of the left ankle joint was assayed by using in situ hybridization technique.Results: In model group

the intensity of pressure of the rats' bilateral ankle joints increased significantly in comparison with that of rats in normal control group

while the intensity values of the ankle joints in high-current ETN

low-current ETN and no-current ETN groups were remarkably lower than that of model group(P<0.01);no significant differences were found among high-current ETN

low-current ETN and no-current ETN groups in the swelling degree(P>0.05)

suggesting that after ETN

the joint swell decreased significantly.Compared with normal group

there was a significant increase in COX-2 mRNA expression in model group(P<0.05)

while in comparison with model group

COX-2 mRNA expression was downregulated significantly in joint synovitis in high-current ETN group(P<0.05).There were no significant differences between low-electric current and model groups

and between model and no-electric current groups in COX-2 mRNA expression(P>0.05).Conclusion: Electrothermo-needle has a favorable effect in anti-arthritis

and high intensity ETN can downregulate the expression of COX-2 mRNA in joint synovitis in arthritis rats.