| BackgroundOsteocarcinoma pain is a kind of chronic pain with unique and complicated mechanism. Changes of osseous tissue of local tumor induce peripheral and central sensitization of the nervous system. Researches have found that a mass of unique hypertrophic astroglia existed in the spinal dorsal horn of osteocarcinoma pain rats.[1] EAAT is the major regulator that maintains the concentration of Glu in the synaptic cleft, and among the5known EAATs subtypes, the GLAST(EAATl) which expressed in glial cells has significant role in the elimination of Glu [2]. Pain and the changes of spinal cord glioblastoma function is closely related with the expression of GLAST. As an endogenous opioid peptide analgesic substance, enkephalin has attracted increasing attention., and many animal experiments have approved that it has significant analgesic effect[3]. Transgenic cellular transplant analgesia has explored new orientation for pain treatment, and in this experiment, the team has packaged the Human preproenkephalin gene (HPPE) with lentiviral vectors in the prophase and successfully screened cells lines with stable expression:Plv-UbC-HPPE/HEK293and UbC-GFP-LV/HEK293(the control cell lines), In this experiments they would be injected into the subarachnoid space of rats in osteocarcinoma pain model to observe its effect on behavior and the expression of the spinal dorsal horn GLAST/EAAT1ObjectiveTo observe the effect of subarachnoid injection Plv-UbC-HPPE/HEK293cells on behavior and the expression of the spinal dorsal horn GLAST/EAAT1in a Rat Model of Osteocarcinoma PainMethod60healthy female SD rats were randomly allocated to4groups (n=15):Group A was blank control; Group B was osteocarinoma model; Group C was osteocarinoma model control group with intrathecal injection of UbC-GFP-LV/HEK293; Group D was osteocarinoma model cell treatment group with intrathecal injection of UbC-GFP-LV/HEK293. The Paw withdrawal latency(PWL) of all the rats in each group was separately measured the day before model surgery and the1、5、10、15、20、21、23、25d after the surgery. On the20d after the surgery, the rats in Group C and Group D were subarachnoid injected with UbC-GFP-LV/HEK293cells and Plv-UbC-HPPE/HEK293cells separately. On the25d after the surgery, L4-L6marrow was taken from all the rats in each group and the expression of the spinal dorsal horn GLAST was detected by immunohistochemistry technique.ResultsCompared with Group A, PWL of Group B and Group C gradually decreased (P<0.05), and the GLAST decreased (P＜0.05). After t the intrathecal injection of Plv-UbC-HPPE/HEK293cells, PWL of Group D increased (P<0.05) and expression of GLAST increased significantly (P＜0.05).ConclusionThe femur injection of MADB-106breast cell lines into SD rats could induce pain behavior changes such as spontaneous pain sensitive, pain induced by walk, pain induced by touch, thermohyperalgesia, etc. Imaging and pathologic examination proves that the model of rats osteocarcinoma pain has established successfully. The expression of GLAST decreased as the osteocarcinomoa pain develops, which indicates that the spinal cord glutamate transporter participated in the formation of osteocarcinoma pain. After the intrathecal injection of plasmid Plv-UbC-HPPE/HEK293, the heat pain threshold of osteocarinoma pain rats has increased significantlly. The inrathecal injection of plasmid Plv-UbC-HPPE/HEK293could increase the expression of the spinal cord GLAST in osteocarcinoma pain rats.which could be one treatment mechnisam of osteocarcinoma pain. |
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