Application of irradiation in limb allo-transplantation , a rat model

本實驗利用大鼠的異體後肢原位移植模 式，探討以致死劑量的放射線全身照射肢 體捐贈者，是否能防止肢體移植中移植物 宿主病的發生。 第一組(n=4)中，組織不相容的BN 大鼠後 肢在移植予LEW 接受者後，於術後第 75+_0.289 天被排斥。第二組(n=6)中，以 cyclosporine (CsA)5 mg/kg/day 與 leflunomide (LEF) 10 mg/kg/day 合併口 服投與肢體接受者，自移植前二天開始直 至移植後第60 天，可有效控制排斥反應， 肢體平均存活天數為75.583+-3.281 天。 停藥後動物(5/5)均自術後63-65 天出現類 似GVHD 的臨床症狀。第三組(n=11)於移植 當天才開始投與CsA+LEF 至移植後第60 天，可有效控制排斥反應，肢體平均存活 天數為83.625+-5.679 天。停藥後動物 (10/11)自術後63-65 天出現類似GVHD 的 臨床症狀。而有一隻動物(1/11)停藥後並 未出現GVHD 症狀，且出現短暫免疫耐性情 形，移植肢體存活至術後122 天(停藥後第 62 天)。第四組(n=6)的肢體捐贈者(BN)於 移植前二天，先接受致死劑量(15Gy)的全 身放照射放射線，肢體接受者(LEW)以 CsA+LEF 合併每日口服投與，自移植前二天 開始至移植後60 天，亦可有效控制排斥反 應，肢體平均存活天數為73.167+-0.872 天。停藥後三隻動物(3/6)自術後63-65 天 出現類似GVHD 之症狀。另三隻動物則未出 現，直到移植肢體達到排斥終短點。各組 間移植肢體感覺與運動功能恢復無異。此 結果顯示，以致死劑量放射線全身照射移 植捐贈者大鼠，並不能完全避免GVHD 之發 生。本研究之GVHD，均經組織免疫化學染 色確認。Following whole limb transplantation from Brown-Norway (BN) to Lewis (LEW) rats, Graft-vs-Host Disease (GVHD) is observed after the administration of immunosuppressive agents is discontinued. In this study, lethal donor irradiation and variation in immunosuppressive schedules were studied in an attempt to prevent GVHD. In group one (n=4, control), all BN limbs were rejected by untreated LEW recipients in 7.5±0.3 days after transplantation. Combination cyclosporine (5 mg/kg/day) and leflunomide (10 mg/kg/day) were given orally to 3 additional groups of LEW recipients until 60 days following transplantation. In group 2 (n=6), drug treatment began 2 days prior to surgery. Over days 63 to 65, all recipients developed signs of GVHD. The limbs survived for 75.6±3.3 days. In group 3 (n=11), drug treatment began on the day of surgery. All but one rat developed signs of GVHD , comparable to that seen in group 2 , over days 63 to 65. The mean limb survival time was 83.6±5.7 days. In group 4 (n=6) donor rats were treated with total body irradiation (15 Gy) 2 days before surgery. Drug treatment of the LEW recipients began 2 days prior to surgery. Three of the 6 rats developed GVHD following discontinuation of drug treatment, and the mean limb survival time was 73.2±0.9 days. The incidence of GVHD was not significantly different (p=0.09, Fisher’s exact test) among the 3 treated groups. These results show that neither lethal donor total body irradiation or temporal variation in the administration of immunosuppressive agents can abolish GVHD in this model of whole limb allotransplantation