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M-K medium and postmortem cytologic damage
Abstract:
Freshly enucleated rabbit eyes were refrigerated at +4 degrees C under standard eye bank conditions for 2, 6, 9, and 21 days. One group of corneas with a scleral rim were excised and placed in M-K medium, stored for 18, 24, or 48 hr at +4 degrees C; they were then removed, and endothelial cell viability was evaluated with nitroblue tetrazolium. The cells were examined by light microscopy and scanning and transmission electron microscopy. A second group of corneas were similarly obtained and then used as donor corneas from 6 mm transplants. Each recipient rabbit was evaluated daily by slit-lamp biomicroscopy and corneal pachometry. Fourteen days postoperatively, the rabbits were sacrificed, the eyes enucleated, and the excised corneas were evaluated in a fashion similar to those of group 1. M-K medium storage protected the morphology and functional integrity of the rabbit corneal endothelium up to 48 hr beyond moist chamber storage for 2, 6, and 9 days. However, M-K medium appeared to have no such effect on corneas that had been moist chamber--stored for 21 days. These results suggest that some human corneas with a prolonged time from death to moist chamber storage may be utilized for corneal transplantation after further storage in M-K medium.
Insights
M-K medium storage preserves corneal endothelium viability for up to 48 hours, extending the usability of donor corneas for transplantation. This method shows promise for corneas with extended post-mortem preservation times.
Area of Science:
- Ophthalmology
- Transplantation Biology
- Cell Biology
Background:
- Corneal transplantation relies on donor tissue viability.
- Standard eye bank storage has limitations on preservation time.
- Optimizing preservation methods is crucial for increasing donor cornea availability.
Purpose of the Study:
- To evaluate the efficacy of M-K medium in preserving corneal endothelial cell morphology and function.
- To determine the optimal storage duration of corneas in M-K medium after initial refrigeration.
- To assess the potential of M-K medium for extending the viability of donor corneas for transplantation.
Main Methods:
- Rabbit eyes were refrigerated, and corneas were stored in M-K medium at +4°C for varying durations (18, 24, 48 hours).
- Endothelial cell viability was assessed using nitroblue tetrazolium and microscopy (light, SEM, TEM).
- Corneas were used in allotransplantation models, with recipient evaluation via slit-lamp biomicroscopy and pachometry.
Main Results:
- M-K medium storage maintained corneal endothelial cell integrity up to 48 hours for corneas stored initially for 2, 6, and 9 days.
- No significant protective effect of M-K medium was observed for corneas stored initially for 21 days.
- Transplanted corneas stored in M-K medium showed preserved morphology and function compared to controls.
Conclusions:
- M-K medium effectively extends the preservation time of corneal endothelium for up to 48 hours beyond standard moist chamber storage.
- This extended preservation is most effective for corneas with shorter initial post-mortem to storage intervals.
- M-K medium holds potential for increasing the utilization of donor corneas, particularly those with moderately prolonged post-mortem intervals.