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Endothelial survival in corneal tissue stored in M-K medium
Abstract:
Cat corneas were stored at refrigerator temperatures in M-K medium (TC-199, 5% dextran), modified M-K medium (TC-199, 1% chondroitin sulfate), or on the intact globe in moist chambers for intervals of one to nine days. Less than 5% of the endothelial cells stained with trypan blue in corneas stored one to four days, regardless of the method of storage. In contrast, after five days, 20% or more of the cells took up the stain in 17 to 21 corneas stored in M-K medium. Although stain uptake indicated nonviability of cells, most of the endothelial cells remained structurally intact when observed by scanning and transmission electron microscopy unless the corneas were incubated in fresh TC-199 for two hours at 35 degrees C before trypan blue staining. In that case, the percentages of disrupted cells observed at each time interval correlated with the percentages of cells that had stained in each cornea. These results indicated that storage in M-K medium did not extend the time donor coreas can be stored before transplantation beyond four days.
Insights
Cat cornea storage for transplantation is limited to four days. Storing corneas longer, especially in M-K medium, significantly increases endothelial cell nonviability and damage, impacting graft success.
Area of Science:
- Veterinary Ophthalmology
- Corneal Transplantation
- Tissue Preservation
Background:
- Corneal transplantation is a vital procedure in veterinary medicine.
- Effective storage of donor corneas is crucial for successful transplantation outcomes.
- Current storage methods require optimization to extend tissue viability.
Purpose of the Study:
- To evaluate the efficacy of different storage methods for cat corneas.
- To determine the maximum storage duration for donor cat corneas before transplantation.
Main Methods:
- Cat corneas were stored at refrigerator temperatures using three methods: M-K medium, modified M-K medium, and intact globe in moist chambers.
- Storage intervals ranged from one to nine days.
- Endothelial cell viability was assessed using trypan blue staining and confirmed with scanning and transmission electron microscopy.
Main Results:
- Corneas stored for one to four days showed less than 5% endothelial cell nonviability across all storage methods.
- After five days, corneas stored in M-K medium exhibited significantly higher nonviability (≥20%).
- Incubation at 35°C prior to staining revealed cell disruption correlating with nonviability, indicating M-K medium's limitations.
Conclusions:
- Storage of cat corneas in M-K medium does not extend the viable storage time beyond four days.
- The findings suggest that current M-K medium storage protocols are insufficient for longer-term preservation of cat donor corneas.
- Further research into optimized storage solutions or techniques is warranted to improve corneal graft longevity in cats.