FK506眼液防治同种异体角膜缘移植免疫排斥反应的实验研究

The study of FK506 eye drops preventing and treating immune rejection on limbal allograft transplantation

目的 探索同种异体角膜缘移植排斥反应规律及FK5 0 6眼液的免疫抑制作用。方法4 8只新西兰白兔随机均分成FK5 0 6组、环孢素A组及非治疗组 ,建立右眼角膜缘缺陷症动物模型 ,1个月后行同种异体角膜缘移植术 ,术后分别用 0 5 %FK5 0 6眼液、1%环孢素A眼液及生理盐水滴眼4周。角膜缘移植术前 1d ,术后 2、4周分别进行角膜中央印迹细胞学检查 ;术前 1d及术后 1～ 8周动态监测外周血T淋巴细胞CD2 5的表达 ;移植术后每日观察植片存活、角膜新生血管和上皮再生情况 ,共 10周 ;分别取术后第 4、8及 10周的角膜缘植片观测淋巴细胞浸润及T淋巴细胞上CD2 5的表达。结果 角膜缘创伤后 1个月 ,所有兔眼角膜中央印迹细胞学检查均为结膜表型 ;同种异体角膜缘移植术后 4周 ,FK5 0 6组和环孢素A组角膜中央保持角膜细胞表型 ,非治疗组呈结膜细胞表型。非治疗组最早出现上皮排斥反应 ,FK5 0 6与环孢素A均可抑制排斥反应的发生 ,停药后环孢素A组先于FK5 0 6组出现上皮排斥反应 (P <0 0 5 )。FK5 0 6组外周血、角膜缘植片T淋巴细胞CD2 5表达及角膜缘植片中淋巴细胞浸润程度低于环孢素A组 ,两组均低于非治疗组 (P <0 0 5 )。结论 同种异体角膜缘移植术后早期应用 0 5 %FK5 0 6眼液滴眼可抑制外周血及植片T淋巴细胞CD2

Objective To evaluate the general cause of limbal allograft transplantation rejection and the effects of the immunosuppressant FK506. Methods Limbal deficiency models were established in 48 New Zealand rabbits, which were randomized into three groups of 16 rabbits each. Limbal allograft transplantation was performed one month later. After transplantation, the FK506 group, the CsA group and the untreated group were treated with FK506 eye drops (0.5 g/L), 1% CsA eye drops and physiological saline, respectively. Graft survival and ocular surface were observed clinically for 10 weeks. Impression cytology was performed on the central cornea of the rabbit one month after limbal ablation, 1 day before allograft transplantation, and two and four weeks after transplantation. The expression of CD25 in peripheral T cells was identified dynamically one day before and one and eight weeks after transplantation. The expression of CD25 on the limbal allograft and lymphocyte infiltration was also identified dynamically the fourth, eighth and tenth week after transplantation. Results Conjunctivalization of corneal epithelium was found in the limbal deficiency model by impression cytology. Two weeks after limbal allograft transplantation, the central corneal epithelium regained corneal phenotype. Four weeks later, the ocular surface of FK506 group and CsA group continued to express corneal phenotype. Epithelium rejection appeared first in the untreated group ( P <0.05), which had the highest level of the lymphocyte infiltration and the expression of CD25 in peripheral blood and allografts after limbal allograft transplantation( P <0.05). Epithelium rejection occurred next with the CsA group. FK506 group epithelium rejection occurred last and had the lowest level of the lymphocyte infiltration and the expression of CD25 in peripheral T cell and limbal allografts. Conclusions Topically administered FK506 eye drops early after limbal allograft transplantation can delay allograft rejection by effectively inhibiting the expression of CD25 in peripheral T cells and limbal allografts. Also, FK506 is more effective than CsA.