Effects on collagen orientation in the cornea after trephine injury

[摘要] Purpose: Structural changes are wellknown to occur in the cornea after injury. The aim of this study was toinvestigate collagen orientation changes in the cornea during ashort-term wound healing process. Methods: Seven bovine corneas wereinjured using a penetrating 5 mm biopsy punch and were subsequentlyorgan cultured for up to two weeks. Six uninjured corneas acted ascontrols. The trephine wounded samples were snap frozen in liquidnitrogen either immediately after injury (0 h) or after 1 or 2 weeks inculture. Control/uninjured samples were snap frozen on arrival (0 h) orafter 1 or 2 weeks in culture. Wide angle X-ray diffraction data werecollected from each cornea at the UK Synchrotron Radiation Source or atthe European Synchrotron Radiation Facility. Data analysis revealedinformation about collagen orientation and distribution in the cornealstroma during wound healing. For histology, two trephine woundedcorneas at 0 h and 1 week and one control/uninjured cornea at 0 h werefixed in 10% neutral buffered formalin and processed for wax embedding.Wax sections were subsequently counterstained with haematoxylin andeosin to observe tissue morphology and the time course of completere-epithelialization. Results: Immediately after injury,collagen organization was altered in a small area inside the wound butremained similar to the control/uninjured sample in the remainder ofthe tissue. After one week, the trephine wounded corneas showedcomplete re-epithelialization and evidence of swelling while collagenadopted a radial arrangement inside and outside the wound. Conclusions: Remarkable changes incollagen fibril orientation were observed in trephine wounded corneas.Orientation changes immediately after wounding are likely to be due tothe mechanical deformation of the tissue during the wounding process.However, tissue swelling and changes in collagen orientation at laterstages probably reflect the processes of tissue repair. Thesedifferences will determine corneal stability and strength followingtrauma and possibly refractive surgery.

[学科分类] 生物化学/生物物理