囓歯類異種間脳移植における新免疫抑制剤FK−506の拒絶反応抑制効果—cyclosporin Aとの比較

The Effect of a New Immunosuppressive Agent, FK-506, on Xenogeneic Neural Transplantation in Rodents : Comparison with Cyclosporin A

　囓歯類異種間脳移植における，FK−506（FK）の拒絶反応抑制効果について，cyclosporin A（CyA）と比較検討した。胎齢14日のラット腹側中脳組織をsolid graftとして，20匹の成雄マウス右側脳室へ定位的に移植し，移植14日後にsacrificeした。組織は，hematoxylin eosin染色，Nissl染色，glial fibrillaryacidic protein（GFAP）免疫染色，Lyt−2免疫染色，およびtyrosine hydroxylase（TH）免疫染色を行った。FK 10.0mg／kg／dayを連日14日間投与した群（n＝5）では，移植胎仔神経細胞の生着および成長が認められたが，CyA 10．Omg／kg／day投与群（n＝5），FK 1.0mg／kg／day投与群（n＝5）およびcontrol群（n＝5）では，拒絶反応が認められた。FKは，心臓，腎臓等における臓器移植と同様に，脳移植においてもCyAより強い拒絶反応抑制効果を持つことが確認された。

The present study was performed to compare the immunosuppressive effect of FK-506 (FK) with cyclosporin A (CyA) in xenogeneic neural trans-plantation in rodents. The solid grafts of embryonic ventral mesencephalic tissue from 14-day rat em-bryos were transplanted into the right lateral ventri-cle of 20 mature male mice using a stereotactic approach, and the mice were sacrificed 14 days after transplantation. The removed brains, which were sectioned coronally, were stained with antibodies against glial fibrillary acidic protein (GFAP) , Lyt-2 or tyrosine hydroxylase (TH) in addition to hematoxylin-eosin and Nissl stainings. The subcu-taneous (s. c.) administration of FK at a dose of 10.0mg/kg daily for 14 days enabled the neural xenografts to survive and grow (n=5) , althoughall of the neural xenografts treated with CyA at a dose of 10.0mg/kg s. c. (n=5) or FK at a dose of 1.0 mg/kg s. c. (n=5) daily for 14 days and ones treated without such an immunosuppressive agent (n=5) were rejected by immunological reactions. We conclude that FK is a more powerful immunosup-pressive agent than CyA in xenogeneic neural trans-plantation as well as in cardiac and renal allograft-ings.