Abstract
Purpose: :
To evaluate the recovery of benzalkonium chloride-induced corneal barrier dysfunction using improved electrodes for measuring corneal trans-epithelial electrical resistance (TER).
Methods: :
Corneal TER was measured in anesthetized Japanese white rabbits (n = 3-6) using a volt-ohm meter (EVOMX) with electrodes placed on the cornea and conjunctival sac. To avoid corneal injury, electrodes were covered with conductive gel. Following TER measurement, the cornea was exposed to 0.02% benzalkonium for 60 s, with the TER measured immediately after exposure and at 6, 12, and 24 h post-exposure. The surface of superficial cells was observed using a scanning electron microscope at each time point. Hanks' Balanced Salt Solution was used as the control.
Results: :
TER of the pre-exposed rabbit cornea was 1229 ± 291 ohm cm2. Immediately after exposure to 0.02% benzalkonium chloride, the surface of superficial cells, including microvilli, was destroyed and TER decreased to 34 ± 12% of the pre-exposure value. The corneal surface injury at 6 and 12 h post-exposure improved gradually, with the TER improving to 42 ± 14% and 67 ± 31%, respectively. By 24 h post-exposure, the corneal surface recovered a normal healthy appearance, and the TER value had increased to 91 ± 25%. There was no change in the superficial cells and corneal TER at any time point in the control group.
Conclusions: :
The corneal surface injury and barrier dysfunction after exposure to 0.02% benzalkonium chloride recovered within 24 h. Quantifying the corneal barrier function in a rabbit model of corneal epithelial-impairment is possible using our improved corneal TER-measurement electrodes.
Keywords: cornea: epithelium • drug toxicity/drug effects • electrophysiology: non-clinical