ABSTRACT
Objective Our previous study showed that cycloxygenase-2 (COX-2) and vascular endothelial growth factor (VEGF) are expressed in choroidal neovascularization (CNV) and the expression of COX-2 is prior to VEGF, indicating that COX-2 is probably one of upstream regulatory factors of VEGF. The aim of this study was to observe inhibition and mechanism of intravitreous injection of celecoxib, a selective COX-2 inhibitor, on experimental choroidal neovascularization in a laser-induced rat model. Methods Retinal photocoagulation was performed in 36 right eyes of 36 male Brown Norway rats to establish CNV models with the laser parameter as follows:wavelength 532 nm, power 80 mW, spot diameter 100 p, m and time shutter 100 ms. Eight or ten spots were irradiated in the position of 1.5 - 2. 0 PD to optic disc. Celecoxib or normal saline solution was intravitreously injected via scleral incision in 18 right eyes of 18 rats, respectively. The thickness and area of CNV were qualified by HE staining(n =3) and by choroidal flatmount (n =3) at day 14 after photocoagulation under the light microscope. The expressions of VEGF and COX-2 in RPE-choroid-sclera complex were examined by Western blot(n =6) and RT-PCR(n =6) at day 7 after photocoagulation. The experimental procedure followed the Standard of Association for Research in Vision and Ophthalmology. The license for animal administration was obtained. Results After intravitreous injection with celecoxib, the thickness and area of CNV were significantly smaller in celecoxib group than normal saline group on 14 days (69. 75 μm ± 7. 50 μm vs 45. 84 μm ± 5. 59 μm in thickness and 87 854 pixel~2 ± 6 735 pixel~2 vs 61 101 pixel~2 ± 6 314 pixel~2 in area, P =0.00). The expressions of VEGF protein and mRNA were obviously lower in celecoxib group compared with normal saline group(t = 3. 755, P = 0.02; t =3. 155, P =0. 03) . No significant difference was found in expression of COX-2 mRNA between the two groups (t = 0. 581, P = 0. 59). Conclusion Intravitreous injection of celecoxib can effectively inhibit CNV by downregulating VEGF level, which is a new approach for the treatment of CNV.
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Objective To investigate the effect of dissociation of the human retinal pigment epithelium (RPE) cells by ficoll hypaque gradient centrifugation. Methods The primary human RPE cells and subcultured human RPE cells were dissociated with ficoll gradient centrifugation solution (d= 1.077 g/ml) and the same divided cells as the control were dissociated with routine normal culture medium centrifugation. The Trypan blue (0.4%) rejection staining was used, and the mouse anti-human monoclonal antibody and fluorescein isothiocyanate (FITC) labeled rabbit anti-mouse IgG were utilized for indirect immunoreactivity for the test of human cytokeratin (CK) in active RPE cells cytoplasm. Flow cytometry assay was used to analyzed the percentages of CK positive staining RPE cells. simultaneously, the cells configuration, growth condition, the rate of clone formation, and the purifying result were observed under the fluorescent and confocal microscope. Results The survival rate and positive rate of CK of RPE cells in experimental group were higher than those in the control ( P
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Objective To investigate the expression and role of inflammatory cytokines like interleukin-1β(IL-1β)、interleukin-6(IL-6)、interleukin-8(IL-8) and tumor necrosis factor-alpha(TNF-α)in epiretinal membranes(ERM)of eyes with proliferative vitreoretinopathy(PVR).Methods Nineteen epiretinal membranes were obtained from eyes undergoing vitrectomy for retinal detachment complicated with PVR and observed by immunohistochemical methods.Results Expression of IL-1β、IL-6、IL-8 and TNF-α were observed in 9、12、11and 15 membranes respectively, with positive staining mostly in the extracellular matrix of epiretinal membranes. Only one membrane showed positive to IL-6 intracellularly, expression for all the cytokines simultaneously in 4 membranes.Conclusion The findings indicate that cytokine-mediated pathways of inflammation are involved in the pathogenesis of PVR.
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Objective To investigate the possible damaging effect of infrasound on ultrastructure and permeability of rats′ blood retinal barrier (BRB). Methods Twenty mature male rats, averagely divided into 5 groups according to the exposure duration, were exposed to infrasound at a 16 Hz frequency and 130 dB sound pressure level in a pressure chamber for 2 hours per day. After exposed for 0, 1 day, 7, 14, and 21 days respectively, ultrastructural changes of rats′ BRB were observed through injection of lanthanum (La) nitrate solution, which was used as a tracer to demonstrate the breakdown of the BRB. Results With prolonging the duration of infrasound exposure, BRB structure lesion, chondriosome tumefaction, endoplasmic reticulum expandedness, membrane disc damage, retinal pigment epithelial cells distortion and putrescence, karyotheca expandedness, and La leakage on each level of retina aggravated gradually. Conclusion Infrasound may cause the breakdown of BRB, and the lesions aggravated with prolonged infrasound exposure time.