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Cytotoxicity studies in ophthalmology
P Lapalus1, M Ettaiche, D Fredj-Reygrobellet
1Laboratory of Pharmacology, School of Medicine, Nice, France.
Abstract:
Ocular tissues and cells are more and more in direct contact not only with drugs but also with biomaterials, such as contact lenses, intraocular implants, corneal shields, and the cell reactivity study is an indispensable step before any clinical and human utilization. The cell toxicity may be direct, by cell membrane damaging, metabolic disturbance, or indirect by mitosis or cell differentiation blocking. In order to evaluate the unwanted effects, cell cultures are performed according to the drug or to the biomaterial to be tested: conjunctival and corneal epithelial cells, lens epithelium, ciliary processes epithelium... In this report, the cytotoxicity of three substances were evaluated on corneal cultured cells: Benzalkonium chloride (BAK), an ophthalmic preservative; Novesine (Oxybuprocaine + BAK), local anaesthetic; Neosynephrine (Phenylephrine chlorydrate), a commonly used mydriatic in ocular surgery. Results of cell counting (cell viability) are given according to curves and histograms (percentage of dead cells depending on time and doses). These data are discussed according to the different mechanisms of action of the three drugs BAK and Oxybuprocaine were found to exert a more direct cell toxicity whereas phenylephrine chloride acted indirectly by causing the sloughing of the cell monolayer.
Insights
Ocular cell toxicity from common ophthalmic drugs like Benzalkonium chloride (BAK) and phenylephrine hydrochloride was assessed. BAK and oxybuprocaine showed direct toxicity, while phenylephrine caused indirect cell damage.
Area of Science:
- Ophthalmology
- Toxicology
- Cell Biology
Background:
- Ocular tissues interact with drugs and biomaterials, necessitating cell reactivity studies.
- Cell toxicity can be direct (membrane damage, metabolic issues) or indirect (mitotic/differentiation blockage).
Purpose of the Study:
- To evaluate the cytotoxicity of Benzalkonium chloride (BAK), Novesine (Oxybuprocaine + BAK), and Neosynephrine (Phenylephrine chlorydrate) on cultured corneal cells.
Main Methods:
- Cultured corneal cells were exposed to varying doses and times of the test substances.
- Cell viability was assessed using cell counting, presented as curves and histograms.
Main Results:
- Benzalkonium chloride (BAK) and oxybuprocaine demonstrated direct cytotoxicity.
- Phenylephrine hydrochloride exhibited indirect toxicity by causing cell monolayer sloughing.
Conclusions:
- Different ophthalmic drugs exhibit distinct mechanisms of ocular cell toxicity.
- Understanding these mechanisms is crucial for safe clinical and human use of ocular agents.