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ABSTRACT: To investigate genotoxicity of the preservative thimerosal (Thi), and the cytoprotective and antioxidant effects of hyaluronic Acid (HA) and hydroxypropyl methylcellulose (HPMC) on Chang conjunctival cells.
Cells were divided into three groups. One group was exposed to Thi at various concentrations (0.00001 %∼0.001 %) for 30 min; the other two groups were pretreated with 0.3 % HA or 0.3 % HPMC for 30 min before the Thi exposure. After cell viability was evaluated, alkaline comet assay and detection of the phosphorylated form of the histone variant H2AX (γH2AX) foci were used to determine DNA damage. Reactive oxygen species (ROS) production was assessed by the fluorescent probe, 2', 7'-dichlorodihydrofluorescein diacetate (DCFH-DA).
A significant change of cell viability was observed after exposure to 0.001 % Thi for 30 min. DNA single- and double-strand breaks were significantly increased in a dose-dependent manner with Thi exposure. In addition, intracellular ROS induced by Thi was dose-dependent, except at 0.001 % less ROS was induced than at 0.0005 %. However, cells pretreated with 0.3 % HA or 0.3 % HPMC showed significantly increased cell survival, decreased DNA damage, and decreased ROS production compared to cells exposed to Thi alone. Pretreatment with 0.3 % HA was found to be even more protective than 0.3 % HPMC.
Thi can induce DNA damage in human conjunctival epithelial cells, probably due to oxidative stress. HA and HPMC are protective agents that have antioxidant properties and can decrease DNA damage induced by Thi. Pretreatment of 0.3 % HA may be more protective of the ocular surface than 0.3 % HPMC.
Albrecht von Graæes Archiv für Ophthalmologie 06/2012; 250(10):1459-66. · 2.17 Impact Factor
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ABSTRACT: We conducted a meta-analysis to evaluate the relationship between smoking and age-related cataract (ARC).
Eligible studies were identified via computer searches and reviewing the reference lists of the key articles. The summary relative risk ratio (RR) or odds ratio (OR) and 95% confidence interval (CI) were calculated. Study-specific risk estimates were pooled using a random-effects model. Meta-regression to assess heterogeneity by several covariates and subgroup analysis on ARC types were performed.
A total of 13 prospective cohort and eight case-control studies met our inclusion criteria. Ever smoking was statistically significantly associated with increased risk of ARC among cohort studies (OR 1.41, 95% CI 1.23-1.62) and case-control studies (OR 1.57, 95% CI 1.20-2.07). In subgroup analysis, ever smoking exhibited a positive relationship with nuclear cataract (NC; OR 1.66, 95% CI 1.46-1.89) and a marginally significant relationship with posterior subcapsular cataract (OR 1.43, 95% CI 0.99-2.07) in cohort studies. Similar results were found in case-control studies (NC OR 1.86, 95% CI 1.47-2.36; posterior subcapsular cataract OR 1.60, 95% CI 0.97-2.65). Current smokers were at higher risk of ARC than past smokers. No association between smoking and cortical cataract was observed.
The overall current literature suggests that smoking was associated with increased risk of ARC, especially NC. Further efforts should be made to confirm these findings and clarify the underlying biological mechanisms.
Investigative ophthalmology & visual science 05/2012; 53(7):3885-95. · 3.43 Impact Factor
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ABSTRACT: To evaluate the effects of 17-β-estradiol on hyperosmolar stress-induced proinflammatory cytokine production of interleukin (IL)-6, IL-1, and tumor necrosis factor-alpha (TNF-α) in SV40-immortalized human corneal epithelial cells (hCECs) and the regulatory effects of the mitogen-activated protein kinase (MAPK) signaling pathways in this process.
SV40 hCECs cultured in normal osmolar media were switched to a higher osmolarity (450 mOsM) by adding NaCl with or without pretreatment with 17-β-estradiol. Real-time polymerase chain reaction and ELISA were applied to characterize IL-6, IL-1, and TNF-α gene and protein expression. Cells were treated for 15-60 min, lysed in radioimmunoprecipitation assay (RIPA) buffer and subjected to a western blot with phospho (p)-specific antibodies against extracellular signal-regulated protein kinase 1/2 (ERK1/2), P38 kinase, and c-Jun N-terminal kinase 1/2 (JNK1/2).
The expression and production of IL-6, IL-1, and TNF-α in SV40 hCECs increased when the media osmolarity was switched to 450 mOsM. Pretreatment with 10(-10) M 17-β-estradiol greatly inhibited the increased expression and production of IL-6, IL-1, and TNF-α induced by hyperosmolarity, whereas with the administration of SB203580 (10 μM), an inhibitor of the p38 pathway, the inhibiting effect of 17-β-estradiol disappeared. The western blot results showed that the increased phosphorylation level of p38 caused by hyperosmolarity was greatly inhibited by 17-β-estradiol.
17-β-estradiol greatly inhibited the expression and production of proinflammatory cytokines IL-6, IL-1, and TNF-α, which were stimulated by hyperosmolarity in SV40-immortalized hCECs. The results also suggested that the p38 MAPK signaling pathway was involved in the regulatory effects of estrogen on hCECs. These findings may contribute to an understanding of the etiologic roles and therapeutic implications of the hormone estrogen in dry eye disease.
Molecular vision 01/2012; 18:1115-22. · 2.20 Impact Factor
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ABSTRACT: To investigate the toxic effects of benzalkonium chloride (BAC), a preservative commonly used in ophthalmic preparations, on DNA single- and double-strand breaks in immortalized human corneal epithelial cells (HCEs).
HCEs were treated with BAC in concentrations ranging from 0.00005% to 0.001% for 30 min. Cells were examined immediately after BAC exposure and after 24-h recovery. Alkaline comet assay was used to detect DNA single-strand breaks (SSBs). Immunofluorescence microscope detection of the phosphorylated form of histone variant H2AX (γH2AX) foci indicated DNA double-strand breaks (DSBs). Cell viability was measured by the MTT test.
A significant increase of SSBs, detected by alkaline comet assay, was observed in a dose-dependent manner with BAC exposure in HCEs at concentrations of 0.00005% and higher. Such BAC treatment also exhibited a dose-dependent increase in DSBs, evaluated by number of γH2AX foci. In addition, a significant change in the relative cell survival rate of HCEs was observed after exposure to 0.001% BAC for 30 min. Although the toxic effects of BAC could be partly repaired after 24 h of cell recovery, SSBs and DSBs in HCEs were still present after BAC removal.
The results demonstrated that exposure to BAC in HCEs, even at low concentrations, could induce DNA strand breaks, which were present after BAC removal. Cell survival analysis indicated that BAC-induced DNA damage was correlated with the cytotoxic effects.
Albrecht von Graæes Archiv für Ophthalmologie 08/2011; 249(11):1681-7. · 2.17 Impact Factor
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ABSTRACT: The aim of this study was to investigate hyaluronic acid (HA) protection on cultured human corneal epithelial cells (HCEs) against benzalkonium chloride (BAC)-induced DNA damage and intracellular reactive oxygen species (ROS) increase.
Cells were incubated with different concentrations of BAC with or without the presence of 0.2% HA for 30 min. DNA damage to HCEs was examined by alkaline comet assay and by immunofluorescence microscopic detection of the phosphorylated form of histone variant H2AX (γH2AX) foci. ROS production was assessed by the fluorescent probe, 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA). Cell apoptosis was determined with annexin V staining by flow cytometry.
HA significantly reduced BAC-induced DNA damage as indicated by the tail length (TL) and tail moment (TM) of alkaline comet assay and by γH2AX foci formation, respectively. Moreover, HA significantly decreased BAC-induced ROS increase and cell apoptosis. However, exposure to HA alone did not produce any significant change in DNA damage, ROS generation, or cell apoptosis.
BAC could induce DNA damage and cell apoptosis in HCEs, probably through increasing oxidative stress. Furthermore, HA was an effective protective agent that had antioxidant properties and could decrease DNA damage and cell apoptosis induced by BAC.
Molecular vision 01/2011; 17:3364-70. · 2.20 Impact Factor
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ABSTRACT: To identify the mutation in polyadenylate-binding protein nuclear 1 gene (PABPN1, previously termed PABP2) in a Chinese family with autosomal, dominantly inherited oculopharyngeal muscular dystrophy (OPMD).
Clinical and ophthalmologic examinations were conducted on available living family members from three generations. Genomic DNA was extracted from peripheral blood leukocytes of every available family member, and the fragment flanking the (GCG)(n) of the PABPN1 gene was amplified by PCR. Mutations were screened by DNA sequencing. Photographs of deceased family members were examined for signs of OPMD.
Clinical features of OPMD were found in all patients in generation II except the youngest sister, and no clinical manifestations were found in generation III. Mutation sequencing demonstrated that (GCG)₆ in the wild PABPN1 gene was expanded to heterozygous (GCG)₁₁ in all affected family members and in some but not all unaffected members.
In a Chinese family with autosomal dominantly inherited OPMD, a heterozygous (GCG)₁₁ expansion was identified in all affected family members and in several young unaffected members.
Molecular vision 01/2011; 17:1350-4. · 2.20 Impact Factor
