神经氨酸酶预处理供体骨髓细胞延长大鼠异体移植物成活时间的观察

目的筛选神经氨酸酶(Neu)预处理供体骨髓细胞(dBMCs)的最佳浓度,使经大鼠尾静脉注射该浓度Neu后的dBMCs偏向性分布于受体肝脏,并观察Neu预处理dBMCs(Neu-dBMCs)联合环孢素A(CsA)短期应用对异体皮片成活时间的影响。方法供体为雄性SD大鼠49只,受体为雌性Wistar大鼠49只。常规制备dBMCs并留取供体皮片备用。Neu预处理浓度筛选实验：按Neu终浓度将26只受体大鼠随机分为0、0．5、1．0、2．0 U/ml 4组(各组分别为6、8、6、6只),用上述4种浓度Neu预处理dBMCs,以~(99m)Tc-SnCl_2法标记,再经受体尾静脉注入,5h后取受体各主要器官,测定其放射性活度,计算出各器官的放射性活度占全部所测器官总放射性活度的百分比,筛选出使dBMCs偏向性分布于受体肝脏的最佳Neu预处理浓度。异体皮片移植实验：将余下23只受体大鼠随机分为对照组、dBMCs组和Neu-dBMCs组,每组均行异体皮片移植,其中后两组在手术当天经尾静脉分别输注dBMCs和Neu-dBMCs(Neu为筛选出的最佳浓度),并分别于术后第2、5天腹腔注射CsA (10 mg/kg),观察各组异体皮片的成活情况。结果在Neu预处理浓度为1．0U/ml时,受体肝脏内dBMCs呈偏向性分布,其百分比为(75．3±9．8)%,明显高于其他浓度组,与0 U/ml组[(58．9±4．2)%]比较差异有统计学意义(P＜0．01)。1．0 U/ml为Neu的最佳浓度。Neu-dBMCs组的同种异体皮片成活时间较dBMCs组明显延长,两组比较差异有统计学意义(P＜0．05)。这两组异体皮片成活时间均较对照组明显延长(P＜0．01)。结论适当浓度的Neu预处理可增强dBMCs与肝脏的亲和性,使经外周静脉输注的dBMCs偏向性分布于受体肝脏内。Neu-dBMCs短期联合应用CsA可明显延长移植的供体皮片成活时间。

Prolongation of the survival of skin allografts by intravenous injection of neuraminidase-treated donor bone marrow cells in rats

OBJECTIVE: To optimize the best concentration of neuraminidase (Neu) that enhances the migration of neuramidinase (Neu)-treated donor bone marrow cells (dBMCs) to the liver, and observe the influence of short-term cyclosporin A(CsA) application combined with intravenous injection (i.v.) of Neutreated dBMCs on the survival of skin allografts. METHODS: The experiment consisted of two parts. For selection of an appropriate concentration of Neu, 26 female Wistar rats were randomly divided into four groups. The dBMCs were prepared by routine method and treated with four concentrations (0, 0.5, 1.0, 2.0 U/ml) of Neu at 37 degrees C for 30 min. The untreated and Neu-treated dBMCs were labeled by 99mTc, and injected via the tail veins to female Wistar rats in each group, respectively. After five hours, the radioactivity of various organs collected from sacrificed rats was measured by a gamma counter, and the values were expressed as percentage of total radioactivity of all organs from the same rat. To observe the survival of skin allograft, 23 male Wistar rats were randomly divided into control group, untreated dBMCs group and Neu-treated dBMCs group. All rats in each group were grafted with skin allografts from male Sprague-Dawley (SD) rats. The dBMCs from the same donor without and with Neu treatment by the concentration selected from the above experiment were injected via the tail veins of female Wistar rats in untreated dBMCs group and Neu-treated dBMCs group, respectively. Rats in untreated dBMCs group and Neu-treated dBMCs group received CsA (10 mg/kg) through intraperitoneal injection (i.p.) at 2 and 5 days post-grafting. Neither dBMCs or CsA were given in the control group. The survival of allograft skin in each group was checked and photographed daily after 5 days post operation. RESULTS: When the concentration of Neu was 1.0 U/ml, the pencentage of dBMCs in liver was (75.3 +/- 9.8) %, which was obviously higher than that in 0 U/ml group [(58.9 +/- 4.2%)], (P < 0.01), indicating that the optimal concentration of Neu was 1.0 U/ml. The survival time of skin allografts in rats of Neu-treated dBMCs group was prolonged significantly in comparison with that of the rats in dBMCs group without Neu treatment (P < 0.01). The survival time in both dBMCs group and Neu-treated dBMCs group was longer that of control group (P < 0.01), and it was prolonged in Neu-treated dBMCs group compared with that in dBMC group. CONCLUSION: Administration of proper concentration of Neu can increase the affinity of dBMCs to the liver, and promote the Neu-treated dBMCs to migrate to liver. The intravenous injection of Neu-treated dBMCs combined with short-term CsA administration can delay the rejection of skin allografts in rats.