Ichijima H, Petroll W M, Jester J V, Cavanagh H D
Department of Ophthalmology, University of Texas, Southwestern Medical Center, Dallas.
Cornea. 1992 May;11(3):221-5.
The effects of benzalkonium chloride (BAK) on the living rabbit cornea were studied by in vivo Tandem scanning confocal microscopy (TSCM) and confirmed by conventional scanning electron microscopy (SEM). Two drops of saline or phosphate-buffered saline (PBS) containing BAK in concentrations of 0.02, 0.01, and 0.005% was applied to rabbit eyes 15 times at 5-min intervals. The solutions were pH 5.5-5.9 (saline) and pH 7.5 (PBS), and osmolarity was 275-280 (saline) and 300-307 mOsm (PBS). Immediately after application of 0.02 and 0.01% BAK, no normal corneal superficial epithelial cells could be imaged by in vivo TSCM. No swelling of the superficial epithelial cells was observed for the control solution without BAK; however, there was a small amount of desquamation. Application of as little as 0.005% BAK caused the superficial epithelial cells to swell and desquamate. The observed desquamation of corneal superficial epithelial cells increased with higher BAK concentrations applied to the eye. One hour after final drug application, inflammatory cells appeared on the surface of the cornea treated with 0.02% BAK. These findings were correlated with SEM observations. Based on the results of this study, we believe that BAK used frequently can produce clinical corneal toxicity and that the cytotoxicity of any topical ophthalmic solutions can be evaluated by in vivo TSCM.
通过体内串联扫描共聚焦显微镜（TSCM）研究了苯扎氯铵（BAK）对活兔角膜的影响，并通过传统扫描电子显微镜（SEM）进行了证实。将两滴浓度分别为0.02%、0.01%和0.005%的含BAK的生理盐水或磷酸盐缓冲盐水（PBS）以5分钟的间隔应用于兔眼15次。溶液的pH值为5.5 - 5.9（生理盐水）和pH 7.5（PBS），渗透压为275 - 280（生理盐水）和300 - 307 mOsm（PBS）。应用0.02%和0.01%的BAK后，体内TSCM立即无法对正常角膜表层上皮细胞进行成像。未添加BAK的对照溶液未观察到表层上皮细胞肿胀；然而，有少量脱屑。仅应用0.005%的BAK就导致表层上皮细胞肿胀和脱屑。观察到角膜表层上皮细胞的脱屑随着应用于眼部的BAK浓度升高而增加。在最后一次给药1小时后，用0.02%的BAK处理的角膜表面出现了炎性细胞。这些发现与SEM观察结果相关。基于本研究结果，我们认为频繁使用BAK会产生临床角膜毒性，并且任何局部眼科溶液的细胞毒性都可以通过体内TSCM进行评估。
