Effect Of Intrathecal Injection With HEK293Expressing Human Preproenkephalin Gene Steadily On The Behavior And The Expression Of PCREB Of The Spinal Dorsal In A Ratmodel Of Bone Cancer Pain

Objective To observe the antinocicepetive effect and mechanism of intrathecalinjection with HEK293expressing human preproenkephalin gene （HH cell,Plv-Ubc-HPPE/HEK293cell）steadily on the behavior and the expression of pCREB(phosphorylated cAMP response element binding protein) of the spinal dorsal in arat model of bone cancer pain.Methods48healthy female adult SD rats (200-220g) were randomly dividedinto2groups: NS group (12, intra-tibial injection with normal saline in5μ l) andBCP group (36, intra-tibial injection with5×10~6MADB-10~6mammary glandcarcinoma cell in5μ l). Changes of pain behavior and damages of the bone wereassessed by paw-withdrawal latency and x-ray before operation as well as7,14,21days after operation. And then BCP group was randomly divided into3groups(n=12each): PBS, GH cell and HH cell at the dose of20μ l were administratedto rats in BCP+PBS, BCP+GH and BCP+HH group respectively three times (at oneday interval). PWTL assessment was finished again. Then intraperitoneal naloxoneand another PWTL assessment were finished. After30min, PWTL assessment wasfinished again. After the rats were sacrificed by perfusion with4%paraform, thelumbar4~6spinal cord was removed and sectioned on a freezing microtome, and thendetected for the expression of pCREB through immunohistochemistry by imageanalysis method.Results1）BCP group: Compared to1day before operation, the PWTL weresignificantly decreased on the7,14,21days after operation(P <0.05). The x-ray ofthe tibia showed clear bone destruction; But NS group remained unchanged.2）BCP+HH group: Compared to BCP+PBS group and BCP+GH group, the PWTL wereall increased (P <0.05) after intrathecal injection with HH cell; But BCP+PBS groupand BCP+GH group unchanged.3） After intrathecal injection, the PWTL inBCP+HH group was longer than before (P <0.05). BCP+HH group’s efficacy were reversed by intraperitoneal naloxone.4） To make comparisons of the amount ofpCREB of the4and6lamination at the dorsal horm: Compared with the BCP+PBSgroup and BCP+GH group, in BCP+HH group, the expression of pCREB weredecreased (P<0.05).Conclusion1）The bone cancer model has been builded sucessfully by thebehavior and x-ray.2）The results provide evidence that the intrathecal injection ofHH cell has been demonstrated to produce behavior variation and antinociception.3）Rats in pain of bone cancer increases pCREB phosphorylation in superficial dorsalhomneurons of spinal cord, which be reduced by the intrathecal injection of HH cell.4）The intrathecal injection of HH cell have a analgesic effect. The mechanisms ofanalgesia may be related to restrain the stimulation of pCREB.