Abstract
Purpose: :
Millions of people suffered from dry eye and have to use artificial tears. Hyaluronic acid, one of the most efficient lubrifiant in ophthalmology, is known to have anti–inflammatory properties in rhumatology. The aim of this work is to investigate in vitro cell tolerance and possible cytoprotective effects of four hyaluronic acid solutions with different molecular weights.
Methods: :
Chang conjunctival cells were treated with four hyaluronic acid (0.02%), molecular weights were 20.103, 100.103, 106 and 2.106 Dalton. Microplate cold light cytofluorometry and inverted fluoerescence microscopy were performed to evaluate cell viability (neutral red test), chromatin condensation (Hoechst 33342 test), reactive oxygen species and superoxide anion overproduction (dichlorofluorescein diacetate and hydroethidine tests), P2X cell death receptor activation (YO–PRO–1 test). The cytoprotective effect of hyaluronic acid towards benzalkonium chloride cytotoxicity was evaluated using the same tests.
Results: :
No alterations were found with the different hyaluronic acids: they did not induce necrosis, nor apoptosis, nor oxidative stress. A one–hour pre–incubation time with hyaluronic acids prevented from the cytotoxic effects of benzalkonium chloride. The more hyaluronic acid molecular weight was high (≥106 Da), the more necrosis and apoptosis due to benzalkonium incubation (0.001% for 15 minutes) were avoided.
Conclusions: :
High molecular weight hyaluronic acids have no cytotoxicity and tend to reduce oxidative stress and toxic effects of preservatives, the cytoprotective effect depending on hyaluronic acid molecular weight. They could be used in dry eye and in ophthalmic drug therapy to improve ocular tolerance.
Keywords: conjunctiva • drug toxicity/drug effects • receptors