Objective To observe the effect of electroacupuncture(EA) on changes of cyclooxygenase(COX)-2 mRNA and protein expression after inflammation occurrence at the back by application of human recombinant IL-1β(hr IL-1β) plus air-pouch in rats

so as to analyze the relativity between EA-induced changes of COX-2 expression and proinflammatory cytokines regulative pathway.Methods Ninety female Wistar rats were randomized into control

model

and EA groups with 30 cases in each.Inflammatory model was established by subcutaneous implantation of a sterilized hollow teflon cylinder(sac

1.5 ml in volume) at the back and intrasaccal injection of hr IL-1β(10 ng/ml).EA(2 Hz

1 mA) was immediately applied to "Quchi"(LI 11) for 30 min.Exudate in the sac was withdrawn at various intervals after hr IL-1β-injection for assaying COX-2 mRNA expression with RT-PCR and protein expression with Western Blotting.Results In comparison with control group

one hour(h) after hr IL-1β-injection

COX-2 mRNA and protein expression levels were up-regulated significantly in model group(P<0.01);while compared to model group

COX-2 mRNA and protein expression levels in EA group were down-regulated considerably(P<0.05).5 h and 24 h after hr IL-1β-injection

COX-2 mRNA expression in model and EA groups was significantly higher than that in control group(P<0.01)

and no significant differences were found between model and EA groups in COX-2 mRNA expression levels(P>0.05).On the contrary

5 h after administration of hr IL-1β

COX-2 protein expression in model group was significantly higher than that in control group(P<0.05).On the 24 h after hr IL-1β-injection

no significant differences were found in COX-2 protein expression levels among control

model and EA groups(P>0.05).Conclusion EA can effectively suppress hr IL-1β-injection induced up-regulation of COX-2 mRNA and protein expression in the rats

suggesting a close relativity between the regulation of proinflammatory cytokines and EA-induced inhibition of COX-2 mRNA and protein expression.