Study On Peripheral Analgesia Of Acu-point Injection With Interleukin-2 In Adjuvant Arthritis Rats

Objective: Recent studies indicate that Interleukin- 2 participate in the mechanism of acupuncture analgesia. It has close relationship with endogenous opioid peptide (EOP). The side effects produced by Interleukin- 2 in clinical applications are serious. Acu-point injection has dramatic curative effects but the dosage is less than other treatments, so it can alleviate the side effects of many drugs. In this thesis, the effects of acu-point injection with low dose of Interleukin- 2 on peripheral analgesia were discussed by tests on adjuvant arthritis(AA) rats. Meanwhile, some theoretical instructions to clinical applications of Acu-point injection with low dose of Interleukin- 2 are provided.Methods: Forty SD rats were randomly divided into five groups: control group (n=8), model group(n=8), Acu-point injection with normal saline group(n=8), intra-peritoneal injection group(n=8), Acu-point injection with Interleukin- 2 group (n=8). The experiments used AA rats (with complete Freund's adjuvant) as the models of inflammatory pain and Xuanzhong and Kunlun points were selected. Targets of pain threshold, local β -endorphin( β -EP), the gene expression of the opiomelanocortin (POMC)mRNA and proenkephalin(PENK)mRNA in the inflamed location of AA rats were observed. Meanwhile, immunohistochemistry and in situ hybridization histochemistry were adopted.Results:1. After treatment, compared with model group, Acu-point injection with normal saline group, intraperitoneal injection group, the pain threshold of AA rats in Acu-point injection with Interleukin-2 group increased significantly(P<0.01), but had no difference with control group(P>0.05).2. The syntheses and releases of the β -EP in the inflamed location of AA rats in Acu-point injection with Interleukin-2 group were significantly higher than thoseof model group, Acu-point injection with normal saline group, intraperitoneal injection group(/)<0.01).3. The gene expression of the POMCmRNA in the inflamed location of AA rats in Acu-point injection with Interleukin-2 group were significantly higher than that in model group, Acu-point injection with normal saline group, intraperitoneal injection group(P<0.01).4. Compared with model group, Acu-point injection with normal saline group, intraperitoneal injection group, the gene expression of the PENKmRNA in the inflamed location of A A rats in acu-point injection with Interleukin- 2 group had no difference(P>0.05).Conclusion: The results indicate that Acu-point injection with low dose of Interleukin-2 has more effective analgesia for inflammatory pain contrasted with other groups meanwhile promotes syntheses and releases of P -EP and the gene expression of POMCmRNA, but has no effect on the gene expression of PENK mRNA in the inflamed location of AA rats. So it is a treatment that Acu-point injection with low dose of Interleukin- 2 for inflammatory pain.