Related Experiment Videos
Keratocyte loss after different methods of de-epithelialization
Purpose:
To evaluate the response of corneal stromal cells to different types of superficial injury.
Methods:
Twenty-two rabbits were randomized into five groups of four (with 2 untreated controls), and their corneas de-epithelialized (1) with a blunt instrument alone; (2) with an instrument and application of 100% ethanol, 0.5% proparacaine, or 4% cocaine; or (3) with the excimer laser. Twenty-four hours after surgery, the eyes were enucleated, and histologic changes were quantitated.
Results:
All the methods of de-epithelialization used resulted in a decrease in the number of keratocytes relative to the control numbers (P = 0.0001). There is a significantly greater decrease in keratocyte counts with 0.5% proparacaine and 100% ethanol when compared with eyes injured by mechanical means, with 4% cocaine, or with the excimer laser (P = 0.009). All treatment groups showed more polymorphonuclear leukocytes than did controls (P < 0.0001). Mechanical de-epithelialization alone or in conjunction with proparacaine produced the least inflammatory response, but de-epithelialization with the laser was associated with a greater inflammatory response (P < 0.0001).
Conclusions:
All methods of de-epithelialization produced a significant decrease in rabbit cornea stromal keratocytes 24 hours after injury, associated with acute inflammation. Thus, it may be appropriate to avoid using chemicals, or if chemicals are used, to at least avoid using 100% ethanol. The applicability of these findings to humans has not yet been established.
Insights
Superficial corneal injury in rabbits significantly reduced keratocytes (stromal cells). Chemical agents like ethanol and proparacaine caused greater cell loss and inflammation than mechanical or laser methods.
Area of Science:
- Ophthalmology
- Corneal Biology
- Cellular Response to Injury
Background:
- Corneal stromal cells, known as keratocytes, are crucial for maintaining corneal structure and transparency.
- Superficial corneal injuries can impact keratocyte populations and lead to inflammation.
- Understanding the differential response of keratocytes to various injury methods is vital for clinical practice.
Purpose of the Study:
- To compare the effects of different superficial de-epithelialization methods on rabbit corneal stromal cells.
- To assess the inflammatory response associated with each injury type.
Main Methods:
- Rabbit corneas were subjected to de-epithelialization using mechanical methods, chemicals (ethanol, proparacaine, cocaine), or an excimer laser.
- Histologic analysis was performed 24 hours post-injury to quantify keratocyte numbers and inflammatory cell infiltration.
- Control groups received no treatment.
Main Results:
- All de-epithelialization methods significantly decreased keratocyte counts compared to controls.
- 0.5% proparacaine and 100% ethanol resulted in a more pronounced keratocyte reduction than mechanical injury, 4% cocaine, or excimer laser.
- All injury groups exhibited increased polymorphonuclear leukocytes, indicating inflammation. Mechanical methods with or without proparacaine showed the least inflammation, while laser injury induced more inflammation.
Conclusions:
- Superficial corneal injury, regardless of method, leads to a significant loss of keratocytes and acute inflammation within 24 hours.
- Chemical agents, particularly 100% ethanol, should be used with caution due to their detrimental effect on keratocytes.
- Further research is needed to determine the clinical relevance of these findings in human corneas.