The Experimental Study Of Analgesia Indused By APA Microencapsulated Bovine Chromaffin Cells Transplantation To The Spinal Subarachnoid Space

IntroduntionThe reserch of foreign and our labs have shown that transplanting adrenal medullary tissure or isolated chromaffm cells into the spinal subarachnoid space induced a long-lasting analgesia. Alginate-polylysine-alginate(APA) microcapsule is semimembrane which can isolate grafts with immune system and prevent immunological reaction. Our previous studies have indicated that APA-BCCs could prolong the rat acute pain threshold rising and relieve pain of cancer patients. There are many problems to be study such as analgesia effect and mechanism, operation security and immuisolated effect of APA microcapsule.ObjectivesTo know more about proliferation and function of BCCs; to study the analgesia effect and mechanism to chronic pain of APA-BCCs transplantation and its operation security; to provide more experiment data about APA-BCCs transplantation for analgesia.Materials and MethodsWe labeled BCCs with PI, then checked cell cycle with flow cytometry machine(FCM). The morphological and functional specificities of BCCs were observed with sucrose-phosphate-glyoxylic acid(SPG) fluorescence-7-dyeing and tyrosine hydroxylase(TH), dopamine beta hydroxylase( DBH), Enkephalin immunocytochemical dyeing. We assessed norepinephrine(NE), epinephrine(E) and leucine-enkephalin(L-EK) secretion of APA-BCCs and BCCs in vitro with high performance liquid chromatography(HPLC) and radioimmunoassay(RIA). Then we transplanted different grafts into the spinal subarachnoid space of thirty CCI rats(10 for APA-BCCs, 10 for hollow microcapsule and 10 for nothing ), seven sheep(3 for APA-BCCs, 2 for BCCs and 2 for hollow microcapsule) and six advanced cancer patients(all for APA-BCCs). We checked the changes of allodynia and hyperalgesia of CCI rat after transplantation. Also we checked concentration of NE, E and L-EK in sheep and patient cerebrospinal fluid before and after transplantation. The patient intensity of pain was assessed by VAS and the dose of analgesic taken was recorded. Meanwhile, we assayed immune reactions of sheep to implant and antigenicity of APA-BCCs to check the ability of APA microcapsule to prevent immune reaction.ResultsBCCs are SPG, TH, DBH and Enk positive and low proliferation. BCCs and APA-BCCs can secret CA and L-EK in vitro and nicotine can stimulate their secretion. There is no significant difference in L-EK concentration between APA-BCCs and BCCs(P>0.05). The CCI rat allodynia and hyperalgesia were alleviated after APA-BCCs transplantation for more 42 days. The concentration of CA and L-EK in sheep CSF didn't increased after transplantation of hollow MC, increased after BCCs transplantation within 14days and APA-BCCs transplantation within 90 days. After transplantation, the patients VAS scores declined markedly, the dose of the analgesic decreased and levels of CA and L-EK in CSF increased significantly. APA-BCCs didn't evoke xenogeneic mouse lymphocyte proliferation when BCCs did. There were no significant changes of sheep immune items and no lymphocyte appeared in sheep CNS after APA-BCCs transplantation. Even after 3 months, we found APA-BCCs alive in spinal subarachnoid space.ConclusionBCCs are monoamine and enkephalin positive cells with low proliferation. APA-BCCs transplantation can increase the concentration of analgesia materials in CNS when show potent analgesia effect. The APA microcapsule has a marked immuisolated effect to prevent immune reaction. It is safe and feasible to transplant APA-BCCs into spinal subarachnoid space as a possible ultralente treatment for pain.