ヒト角膜のサル角膜への全層角膜移植

Experimental studies on penetrating heterokerato-plasty with human corneal graft in monkey eye

緒言

　近来eye bankの普及化，角膜graftの保存方法及び手術器械と手術技術の進歩で，ヒトの同種全層角膜移植の成功率は大いに向上した。しかし，なおいくつかの国では宗教的，または他の原因でeye bankの設立はまだいろいろな困難があり，角膜graftの入手が容易でなく，何時でも即時に患者の手術要求に満足できない所がある。それでは，もし緊急手術の場合に，即時に同種角膜graftが手もとにない場合，何かの種類の異種角膜graft使用の可能性がないものか？　すなわち異種全層角膜移植は成功の可能性があるかどうか？この意味で，私たちは異種角膜移植の研究の第一歩として，1983年からヒト角膜graftのサルへの全層角膜移植の実験を開始し，そのうち移植graftが1年以上透明保持し得た5例に対して長期観察を行い，また移植graftの角膜内皮のspecular microscope及び走査電顕検査を行ったので，その結果を報告する。

The experimental data were devided into three groups:

1 ) The first group: 5.5mm human donor corneal grafts were transplanted into 5.0mm recipient beds of 3 monkey eyes (No.1-No.3). The results showed that the grafts of No. 1 and No. 2 monkey were transparent for 20 and 15 months at least, and have been still observed continuously.

2) The secoud group: 6.2mm human grafts, into 6.0mm recipient beds of 3 monkeys (No. 4-No. 6). The human graft of No.4 monkey were transparent for 25 months, and other human grafts of No.5 and No.6 monkeys were transparent for 13 and 12 months.

3) The third groups: 7.5mm human grafts, into 7.0mm recipient beds of 3 monkeys (No.7-No.9). The results revealed that all of human grafts in this group maintained transparent only for 4-7 months,and then became semitransparent or opaque.

Otherwise, the examination by specular micros-copy and SEM was used. The endothelium density of No.6 monkey was 2570cells/mm², observed by 8 months after operation. But it was decreased to 1800cells/mm², observed by 13 months after opera-tion. The rate of graft endothelium decrement is 29. 9% for 5 months. This is faster than physiological decrement. Endothelium cell of human grafts could be alive in the monkey cornea at least for 13 months under the observation by SEM.

The graft rejective reaction treated by dexameth-asone in very effective in early or mild cases, but it could not be cured effectively in later or severe cases with rejective reaction or with evident cor-neal vascularization.

The first and second groups of animal experimen-tal model was successfully done, so that it is proposed that this deta may afford available opin-ion in the field of penetrating hetero-keratoplasty.