Publications (2)5.6 Total impact
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Article: Effects of dexamethasone on human trabecular meshwork cells in vitro.
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ABSTRACT: PURPOSE: To study the effects of dexamethasone sodium phosphate (Dex) on human trabecular meshwork (HTM) cells in vitro. METHODS: HTM cells were treated with Dex 2 mg/ml, 1 mg/ml, 0.5 mg/ml, 0.25 mg/ml, 0.1 mg/ml, or 0.05 mg/ml for 24 h. Cell viability was measured by a trypan blue exclusion test. Caspase-3/7, -8, -9 and -12 activities were measured by fluorochrome assays as mean signal intensity (msi) to assess apoptosis. Mitochondrial dehydrogenase activity was determined by a WST assay to quantify mitochondrial damage. RESULTS: Mean cell viabilities of HTM cells exposed to Dex at the higher doses of 2 mg/ml, 1 mg/ml, and 0.5 mg/ml were reduced: 11.9 % ± 3.5 (P < 0.001), 31.2 % ± 3.2 (P < 0.001), and 76.6 % ± 4.4 (P < 0.01). At the lower doses of 0.25 mg/ml, 0.1 mg/ml or 0.05 mg/ml, no significant cell viability reductions were seen: 96.3 % ± 0.7 (P > 0.05), 95.3 % ± 2.5 (P > 0.05) and 93.8 % ± 2.3 (P > 0.05), respectively compared to untreated HTM cells (97.0 % ± 1.9). Caspase-3/7 activity (msi) of HTM cells exposed to Dex 2, 1 or 0.5 mg/ml was 21068 ± 2498 (P < 0.001), 26994 ± 3104 (P < 0.001) and 20416 ± 1150 (P < 0.001) compared to untreated HTM cells 1148 ± 803. Caspase-9 activity (msi) of HTM cells after exposure to Dex 2, 1 or 0.5 mg/ml was 14188 ± 1203 (P < 0.001), 13256 ± 1564 (P < 0.001) and 15041 ± 1584 (P < 0.001) compared to untreated HTM cells 1748 ± 524. The lower doses of Dex did not significantly increase caspase-3/7 or -9 activities. There were no increases for caspase-8 or -12 activities at any of the tested Dex doses. The WST assay showed mitochondrial dehydrogenase activities of 14.3 ± 0.7 (P < 0.001), 9.6 ± 0.3 (P < 0.001) and 56.0 ± 7.6 (P < 0.001) at 2 mg/ml, 1 mg/ml and 0.5 mg/ml Dex compared to untreated HTM cells (186.1 ± 15.0). CONCLUSIONS: Dex at 0.25, 0.1 and 0.05 mg/ml clinical dose did not cause significant reduction in cell viability, increased apoptosis, or mitochondrial dysfunction of HTM cells in vitro. At high doses (2, 1 or 0.5 mg/ml) Dex caused apoptosis via mitochondrial pathways.Albrecht von Graæes Archiv für Ophthalmologie 05/2013; · 2.17 Impact Factor -
Article: Inhibition of apoptosis in human retinal pigment epithelial cells treated with benzo(e)pyrene, a toxic component of cigarette smoke.
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ABSTRACT: To study the inhibitory effects of some agents or drugs (inhibitors) on benzo(e)pyrene (B(e)P)-induced cell death and apoptosis on human retinal pigment epithelial (ARPE-19) cells in vitro. ARPE-19 cells were pretreated with varying concentrations of different classes of inhibitors (calpain, benzyl isothiocyanate [BITC], simvastatin, epicatechin, genistein, resveratrol, and memantine) before B(e)P exposure. Cell viability (CV) was determined by a trypan blue dye-exclusion assay. Caspase-3/7 and caspase-9 activities were measured by fluorochrome assays. The production of reactive oxygen/nitrogen species (ROS/RNS) was measured with 2',7'-dicholorodihydrofluorescein diacetate dye assay. At 30-microM concentrations, the genistein, resveratrol, and memantine inhibitors were able to reverse significantly the loss of cell viability, the activation of caspase-3/7 and caspase-9, and the production of ROS/RNS in ARPE-19 cell cultures. Memantine was the most potent and genistein was the least effective inhibitor in blocking the B(e)P-induced effects. Calpain, BITC, simvastatin, and epicatechin did not reverse the loss of cell viability in B(e)P-treated ARPE-19 cells. As a matter of fact, at the concentrations studied (15, 30, 45 microM), the BITC plus B(e)P-treated cultures showed significantly lower cell viability than the B(e)P-treated culture alone, suggesting BITC-related toxicity. Genistein, resveratrol, and memantine can reverse the apoptosis and oxidant production generated by B(e)P, a toxic element of smoking. These inhibitors may be beneficial against retinal diseases associated with the loss of RPE cells.Investigative ophthalmology & visual science 12/2009; 51(5):2601-7. · 3.43 Impact Factor
