骨髓输注联合阻断共刺激通路延长大鼠皮肤移植物的存活时间

Bone marrow infusion in combined with costimulatory signal system blockade prolonged the survival time of grafted skin in rats

目的探讨骨髓输注联合阻断共刺激通路对大鼠移植皮肤存活的影响及可能机制。方法以Lewis大鼠为受者，皮肤移植前经尾静脉输注供者（BN大鼠）骨髓细胞2×10^8个，并于骨髓输注当天、输注后第2、4、6及8天腹腔注射抗CD25单克隆抗体，同时按照分组要求腹腔注射细胞毒性T淋巴细胞相关抗原4融合蛋白（CTLA4Ig组）、抗CDl54单克隆抗体（抗CDl54单抗组）以及CTLA4Ig和抗CDl54单克隆抗体（联合处理组），于骨髓输注后第8天移植BN大鼠的皮肤。另以仅行皮肤移植者为对照（对照组）。观察各组移植物抗宿主病（GVHD）的发生情况、外周血中供者细胞嵌合率、T淋巴细胞凋亡率及移植皮肤的存活时间。结果各组均未观察到GVHD的发生。骨髓输注后第7天即可在CTLA4Ig组、抗CDl54单抗组及联合处理组观察到嵌合现象，至第21天时，嵌合率仍维持于一定水平，联合处理组明显高于其它三组（P〈0．01）。骨髓输注后第7及21天，CTLA4Ig组、抗CDl54单抗组及联合处理组间两两比较，T淋巴细胞凋亡率的差异无统计学意义，但均显著高于对照组（P〈0．05，P〈0．01）。CTLA4Ig组、抗CDl54单抗组及联合处理组移植皮肤的存活时间显著长于对照组（P〈0．01），联合处理组移植皮肤存活时间为（16．7±3．1）d，明显长于CTLA4Ig组和抗CDl54单抗组（P〈0．05）。结论骨髓输注联合阻断共刺激通路能够延长移植皮肤存活时间，其机理可能与诱导嵌合和T淋巴细胞凋亡有关。

Objective To explore the effect of bone marrow infusion in combined with costimu- latory signal system blockade on the survival time of grafted skin in rats and its possible mechanisms. Methods Lewis rats as receptors received 2 × 10^8 bone marrow cells from inbred BN rats through tail vein on day 0 and anti-CD 25 monoclonal antibody on day 0,day 2,day 4,day 6,and day 8. The receptors also received CTLA4Ig （CTLA4Ig group）,anti-CD 154 monoclonal antibody （anti-CD 154 monoclonal antibody group）, CTLA4Ig and anti-CD 154 monoclonal antibodies （combined treatment group） in accordance with the requirements of each group. Each group received skin graft from BN rats on day 8. There was also control group in which receptors just received skin grafting. The symptom of GVHD, chimerism rate in peripheral blood, apoptosis of T cells and the survival time of grafed skin were observed. Results GVHD was not observed in all groups. The chimerism could be observed in CTLA4Ig group,anti-CD 154 monoelonal antibody group and combined treatment group on day 7. On day 21 chimerism could also be detected. The chimerism rate in combined treatment group was significant higher than that in other groups （P〈0. 01）. In CTLA4Ig group, anti-CD 154 monoelonal antibody group and combined treatment group,there was no significant difference in apoptosis of T cells on day 7 and day 21, but there was significant difference between experimental groups and control group （P〈0. 05, P〈0. 01）. The survival time of grafted skins in CTLA4Ig group, anti-CD 154 monoclonal anti- body group and combined treatment group was significant longer than that in control group （P〈0. 01）. The survival time of grafted skins in combined treatment group was （16. 7 ± 3. 1） days,which was significant longer than that in CTLA4Ig group and anti-CD 154 monoclonal antibody group （P〈 0. 05）. Conclusion Bone marrow infusion in combined with costimulatory signal system blockade prolonged the survival time of grafted skin,and apoptosis of T cells may play an important role in its mechanism.