UVA/リボフラビン架橋後の羊膜脆弱性の評価と超構造変化と生分解への影響

Evaluation and ultrastructural changes of amniotic membrane fragility after UVA/riboflavin cross-linking and its effects on biodegradation.

• Chenming Zhang
• Tingting Du
• Guoying Mu
• Jia Wang
• Xin Gao
• Fumin Long
• Qiaoling Wang

抄録

本研究では、UVA/リボフラビン架橋後の羊水膜の脆弱性と超微細構造の変化を評価することを目的とした。A群(CX群)では18名がUVA/リボフラビン架橋のために10"Zs_200A"minの0.1%リボフラビン溶液に浸漬した。16名をB群(B2群)に入れ、0.1%リボフラビン溶液に10"Zs_200A"min浸漬した。浸漬後、A群およびB群の膜を角膜保存液に移した。15枚はC群、直接角膜保存液に移した。架橋前と架橋後の羊膜組織の生体力学的および超構造的変化を調べた（CX群"Zs_200A"="Zs_200A"13、B2群"Zs_200A"="Zs_200A"11、C群"Zs_200A"="Zs_200A"15）。A群（n"Zs_200A"="Zs_200A"5）とB群（n"Zs_200A"="Zs_200A"5）の羊膜組織をそれぞれウサギの16眼に移植し、羊膜組織の溶解時間を調べた。架橋後、対照群と比較して、羊膜の低ストレス領域（Ｅｌｏｗ）の弾性率が高く、羊膜の高ストレス領域（Ｅｈｉｇｈ）の弾性率が低く、引張強度に有意な差は認められなかった。また、コラーゲン繊維には粗大な竹状の変化が見られた。Ａ群では、結膜移植後４週間で羊膜が溶解し始め、結膜移植後６週間で全ての羊膜が溶解・吸収された。このことから、羊膜架橋後、羊膜の脆さが増し、硬さが増し、コラーゲン繊維の形態が変化していることが示唆された。架橋した羊膜は組織溶解に対する抵抗性を示した。

This study aims to evaluate the changes of fragility and ultrastructure of amniotic membrane after cross-linking by UVA/riboflavin.Forty-nine fresh amniotic membranes were randomly divided into 3 groups. Eighteen were in group A (CX group) and immersed in 0.1% riboflavin solution for 10 min for UVA/riboflavin cross-linking. Sixteen were in group B (B2 group), soaked for 10 min with 0.1% riboflavin. After soaking, membranes in group A and B were transferred into corneal preservation solution. Fifteen pieces were in group C, directly into corneal preservation solution. The biomechanical and ultrastructural changes of the amniotic tissue before and after cross-linking were examined (CX group = 13, B2 group = 11, C group = 15). The amniotic membrane tissue of group A (n = 5) and B (n = 5) was transplanted into 16 eyes of the rabbits, respectively, and the dissolution time of the amniotic membrane tissue was investigated.After cross-linking, compared with the control group, the elastic modulus of the low-stress area of the amniotic membrane (Elow) was higher, while the elastic modulus of the high-stress area of the amniotic membrane (Ehigh) was lower, with no significant difference in the tensile strength. Also, the collagen fibers showed coarse and bamboo-like changes. In group A, amniotic membranes began to dissolve 4 weeks after conjunctiva transplantation, and all amniotic membranes were dissolved and absorbed 6 weeks after conjunctiva transplantation. In group B, some amniotic membrane tissues were still visible 6 weeks after conjunctiva transplantation.This study suggested that after amniotic membrane cross-linking, the brittleness was increased, the hardness was enhanced, and the morphology of the collagen fiber was changed. The cross-linked amniotic membrane showed resistance to tissue dissolution.