COX-inhibitors and ASA; influence on oxidative stress in cultured mouse lens

• Purpose: Several substances such as ASA and COX-inhibitors have been attributed antioxidant properties. The main objectives of this study were to examine possible protection against oxidative damage in cultured mouse lens by ASA, specific COX-2 as well as unspecific COX-1-2 inhibitors. Methods: Intact mouse lenses were exposed to acetylsalicylic acid (0.03 mM), celecoxib (0.5 {micro}M), indomethacin (0.5 {micro}M), diclofenac (0.5 {micro}M), and/or H2O2 (100 {micro}M) for 8 days. H2O2 were administered as a single dose each day. Lens transparency was examined every day by light microscopy. The intact lenses were assayed at regular intervals during 6 h for proteolytic activity using the fluorogenic peptide substrate Suc-Leu-Leu-Val-Tyr-AMC (LLVY-AMC) (50 {micro}M) suitable for the calpain and proteasome proteolytic systems. Prior to the oxidative stress experiment, dose-response curves had been performed in a similar manner using doses ranging between 0.5-50 {micro}M for COX-inhibitors, 0.03-3 mM for ASA and 10-100 {micro}M for H2O2. Results: Dose-response experiments showed no effect by COX-inhibitors at 0.5 {micro}M or ASA at 0.03 mM on proteolysis or lens transparency compared to control. Hence, these doses of drugs were used to look at possible protective effects in oxidative stress experiments. Opacification of lenses exposed to a single dose of 100 {micro}M H2O2 each day appeared at day 5. Proteolytic activity of the calpain - proteasome systems in lenses exposed to H2O2 in the presence of ASA, COX-2 or COX-1-2 inhibitors did not differ significantly from lenses exposed to H2O2. No protection against oxidative stress by these substances could be detected with regard to change in lens transparency. Conclusions: The protective effect of ASA, COX-2 and COX-1-2 inhibitors against oxidative damage in the lens may be limited. The mechanisms through which these substances exert their actions with respect to oxidative damage require further studies.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinska och farmaceutiska grundvetenskaper -- Cell- och molekylärbiologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Basic Medicine -- Cell and Molecular Biology (hsv//eng)

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