异体气管移植去抗原性的实验研究

目的探讨移植段气管去除上皮细胞和腺体细胞后异体、异位移植排斥反应的强弱。方法25只雄性SD大鼠作为供体,制备新鲜移植段气管、冷冻移植段气管和去上皮细胞移植段气管。取制备的新鲜移植段气管40个平均分为4组,分别用0、0.1、0.3和0.5mg/ml的蛋白酶溶液,4℃浸泡12h,根据镜下移植段气管上皮细胞和腺体细胞脱落情况及软骨细胞破坏程度确定蛋白酶的最佳浓度。另取30只雄性SD大鼠作受体,均分成3组,分别为:新鲜气管移植组(A组)、冷冻气管移植组(B组)及去上皮细胞移植组(C组),n=10。行左上腹旁正中切口,提出大网膜包绕各移植段气管,于21d后取出移植段气管,行组织学观察及淋巴细胞浸润测定。结果0.3mg/ml蛋白酶能去除移植段气管上皮细胞及腺体细胞,而对软骨细胞无明显损坏。异体植入大鼠腹腔的3组气管软骨均成活,血运建立,其中A组管腔内有肉芽组织,出现坏死、实变;B组有少量肉芽组织;C组管腔内无肉芽组织。A、B、C3组淋巴细胞浸润分别为29.16±2.69、15.17±2.19和11.56±0.87个/Hp,A组与B、C组比较及B组与C组比较,差异均有统计学意义(P<0.05),排斥反应强弱为:A组>B组>C组。结论0.3mg/ml蛋白酶,4℃,浸泡12h的移植段气管,能完全脱上皮细胞和腺体,对软骨细胞基本无损伤,与冷冻法比较去抗原作用更好。一期异体大网膜包裹异位移植后,血运重建且移植段气管成活。

EXPERIMENTAL STUDY ON THE TRACHEAL ALLOGRAFTS WITH DECREASED ANTIGENICITY

OBJECTIVE: To investigate effect of the removal of epithelium and mixed glands from the tracheal allografts on the graft-immunosuppression. METHODS: Fresh untreated tracheal allografts, cryopreserved tracheal allografts, and 10 off-epithelium tracheal allografts were obtained from 25 male SD rats. Fresh untreated tracheal allografts (40) were divided into 4 groups and dipped respectively in the solution of protease XIV in 0, 0. 1, 0.3 and 0.5 mg/ml at 4 C for 12 hours. Thirty recipient male SD rats were randomly and equally divided into group A (fresh untreated tracheal allografts), group B (cryopreserved tracheal allografts), and group C (off-epithelium tracheal allografts). The transplanted allografts were implanted into the abdominal cavity of other rats by being embedded in the greater omentum. Twenty-one days after transplantation, the tracheal graft segments were surgically removed, and then were initially fixed in cold 10% neutral buffered formalin solution for hematoxylineosin staining. Histological observation and lymphocyte infiltration were performed on the grafts to evaluate rejection. RESULTS: The 0.3 mg/ml protease XIV could remove the epithelium and mixed glands of the grafts completely, but did no damage to cartilage. The cartilages of each group all survived and were revascularized. The lumens of group A were filled with granulation and necrosis tissue. In contrast, group B was filled with a few granulation tissues and group C was not at all. The number of lymphocyte infiltration in group A, B, and C was 29.16 +/- 2.69/HP, 15.17 +/- 2.19/HP, and 11.56 +/- 0.87/HP respectively. There was significant difference between group A and both group B and group C (P < 0.05), and there was significant difference between group B and group C (P < 0.05). Therefore, the grade of graft-rejection was group A > group B > group C. CONCLUSION: The 0.3 mg/ml protease XIV can completely remove the epithelium and mixed glands of grafts at 4 C for 12 hours, and it preserves the normal structure of cartilage. The antigenicity of tracheal grafts can be greatly reduced by removing the epithelium and by the cryopreservation. The prior tracheal allograft in the omentum is feasible for the revascularization of the grafts.