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Comparison of Cytotoxic Effects on Rabbit Corneal Endothelium between Preservative-free and Preservative-containing Dorzolamide/timolol.

Kwon J, Heo JH, Kim HM, Song JS - Korean J Ophthalmol (2015)

Bottom Line: Endothelial damage was compared between both eyes by vital staining (alizarin red/trypan blue staining), live/dead cell assay, TUNEL assay, and scanning electron microscopy.The main cause of corneal endothelial toxicity was due to the preservative in the dorzolamide/timolol fixed combination eyedrops, and not the active ingredient.Thus, it appears to be safer to use preservative-free eyedrops during the early postoperative period.

View Article: PubMed Central - PubMed

Affiliation: Department of Ophthalmology, Korea University College of Medicine, Seoul, Korea.

ABSTRACT

Purpose: To evaluate and compare the toxic effects of eyedrops containing a fixed combination of 2.0% dorzolamide and 0.5% maleate timolol with or without preservatives on rabbit corneal endothelium.

Methods: This study was performed with 22 eyes of New Zealand white rabbits. Dorzolamide/timolol eyedrops with preservative (Cosopt group) or without preservative (Cosopt-S group) were diluted with a balanced salt solution at a 1 : 1 ratio. We injected 0.1 mL of diluted Cosopt into the anterior chamber of left eyes and an equal volume of diluted Cosopt-S into the anterior chamber of right eyes. Corneal thickness, corneal haze, and conjunctival injection were measured before and 24 hours after treatment. Endothelial damage was compared between both eyes by vital staining (alizarin red/trypan blue staining), live/dead cell assay, TUNEL assay, and scanning electron microscopy.

Results: Corneal endothelial damage was severe in the Cosopt group. Cosopt-treated eyes exhibited remarkable corneal edema and prominent apoptosis of endothelial cells. In addition, the live/dead cell assay revealed many dead cells in the endothelium, and scanning electron microscopy analysis showed that corneal endothelial cells exhibited a partial loss of microvilli on the surface as well as extensive destruction of intercellular junctions. However, in the Cosopt-S group, corneal edema was mild and the damage to the corneal endothelium was minimal.

Conclusions: The main cause of corneal endothelial toxicity was due to the preservative in the dorzolamide/timolol fixed combination eyedrops, and not the active ingredient. Thus, it appears to be safer to use preservative-free eyedrops during the early postoperative period.

No MeSH data available.


Related in: MedlinePlus

(A) Comparison of the number of dead cells from live/dead cell assay and TUNEL(+) cells in 5 consecutive microscopic fields between the Cosopt and Cosopt-S groups (×400). (B) TUNEL stain of rabbit cornea 24 hours after Cosopt injection. Several TUNEL(+) cells are present in the endothelial cell layer. (C) TUNEL stain of rabbit cornea 24 hours after Cosopt-S injection. TUNEL-positive cells are absent (×400).
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Figure 3: (A) Comparison of the number of dead cells from live/dead cell assay and TUNEL(+) cells in 5 consecutive microscopic fields between the Cosopt and Cosopt-S groups (×400). (B) TUNEL stain of rabbit cornea 24 hours after Cosopt injection. Several TUNEL(+) cells are present in the endothelial cell layer. (C) TUNEL stain of rabbit cornea 24 hours after Cosopt-S injection. TUNEL-positive cells are absent (×400).

Mentions: The live/dead cell assay performed 24 hours after injection revealed that many endothelial cells in the Cosopt group were dead as evidenced by red-stained nuclei (Fig. 2C). However, in the Cosopt-S group, dead cells were rarely observed (Fig. 2D). The median number of dead cells from 5 consecutive microscopic fields (×400) on each eye was 28 in the Cosopt group and 2 in the Cosopt-S group (p < 0.001) (Fig. 3A).


Comparison of Cytotoxic Effects on Rabbit Corneal Endothelium between Preservative-free and Preservative-containing Dorzolamide/timolol.

Kwon J, Heo JH, Kim HM, Song JS - Korean J Ophthalmol (2015)

(A) Comparison of the number of dead cells from live/dead cell assay and TUNEL(+) cells in 5 consecutive microscopic fields between the Cosopt and Cosopt-S groups (×400). (B) TUNEL stain of rabbit cornea 24 hours after Cosopt injection. Several TUNEL(+) cells are present in the endothelial cell layer. (C) TUNEL stain of rabbit cornea 24 hours after Cosopt-S injection. TUNEL-positive cells are absent (×400).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4595261&req=5

Figure 3: (A) Comparison of the number of dead cells from live/dead cell assay and TUNEL(+) cells in 5 consecutive microscopic fields between the Cosopt and Cosopt-S groups (×400). (B) TUNEL stain of rabbit cornea 24 hours after Cosopt injection. Several TUNEL(+) cells are present in the endothelial cell layer. (C) TUNEL stain of rabbit cornea 24 hours after Cosopt-S injection. TUNEL-positive cells are absent (×400).
Mentions: The live/dead cell assay performed 24 hours after injection revealed that many endothelial cells in the Cosopt group were dead as evidenced by red-stained nuclei (Fig. 2C). However, in the Cosopt-S group, dead cells were rarely observed (Fig. 2D). The median number of dead cells from 5 consecutive microscopic fields (×400) on each eye was 28 in the Cosopt group and 2 in the Cosopt-S group (p < 0.001) (Fig. 3A).

Bottom Line: Endothelial damage was compared between both eyes by vital staining (alizarin red/trypan blue staining), live/dead cell assay, TUNEL assay, and scanning electron microscopy.The main cause of corneal endothelial toxicity was due to the preservative in the dorzolamide/timolol fixed combination eyedrops, and not the active ingredient.Thus, it appears to be safer to use preservative-free eyedrops during the early postoperative period.

View Article: PubMed Central - PubMed

Affiliation: Department of Ophthalmology, Korea University College of Medicine, Seoul, Korea.

ABSTRACT

Purpose: To evaluate and compare the toxic effects of eyedrops containing a fixed combination of 2.0% dorzolamide and 0.5% maleate timolol with or without preservatives on rabbit corneal endothelium.

Methods: This study was performed with 22 eyes of New Zealand white rabbits. Dorzolamide/timolol eyedrops with preservative (Cosopt group) or without preservative (Cosopt-S group) were diluted with a balanced salt solution at a 1 : 1 ratio. We injected 0.1 mL of diluted Cosopt into the anterior chamber of left eyes and an equal volume of diluted Cosopt-S into the anterior chamber of right eyes. Corneal thickness, corneal haze, and conjunctival injection were measured before and 24 hours after treatment. Endothelial damage was compared between both eyes by vital staining (alizarin red/trypan blue staining), live/dead cell assay, TUNEL assay, and scanning electron microscopy.

Results: Corneal endothelial damage was severe in the Cosopt group. Cosopt-treated eyes exhibited remarkable corneal edema and prominent apoptosis of endothelial cells. In addition, the live/dead cell assay revealed many dead cells in the endothelium, and scanning electron microscopy analysis showed that corneal endothelial cells exhibited a partial loss of microvilli on the surface as well as extensive destruction of intercellular junctions. However, in the Cosopt-S group, corneal edema was mild and the damage to the corneal endothelium was minimal.

Conclusions: The main cause of corneal endothelial toxicity was due to the preservative in the dorzolamide/timolol fixed combination eyedrops, and not the active ingredient. Thus, it appears to be safer to use preservative-free eyedrops during the early postoperative period.

No MeSH data available.


Related in: MedlinePlus