Objective To observe the effects of bevacizumab on aquaporin 4 (AQP4) expression in human retinal Muuml;ller cells in vitro under hypoxia. To explored the mechanism of treating retinal edema with bevacizumab. Methods Human Muuml;ller cells were cultured using the enzymatic digestion method. Transmission electron microscopic analysis and immunofluorescence staining identified Muuml;ller cells. With semi-quantitative reverse transcription polymerase chain reaction (RT-PCR), the expression of AQP4 mRNA and vascular endothelial growth factor （VEGF） mRNA in Muuml;ller cells cultured under different concentration of COCl2 for different hours were observed. The expression of AQP4 mRNA in Muuml;ller cells cultured using CoCl2 precultured with 200 mu;g/ml bevacizumab was measured. Results More than 95% of primary cells showed positive reaction to glial fibrillary acidic protein, glutamine synthetase, vimentin and alpha;-smooth muscle actin with immunofluorescence staining. Characteristic 8-10 nm intracellular filaments could be seen in the cytoplasm viewed with transmission electron microscopy. The results using RT-PCR showed that CoCl2 increased the AQP4 and VEGF mRNA expression in Muuml;ller cells in a dose and time dependent manner (r=0.952, 0.954;P＜0.05). The expression of AQP4 mRNA in Muuml;ller cells was increased by VEGF (F=12.43,P＜0.05). The expression of AQP4 mRNA was significantly decreased by bevacizumab (F=2 370.37，P＜0.05). Conclusion Bevacizumab can down-regulate the expression of AQP4 mRNA in human Muuml;ller cells under hypoxic conditions partially by VEGF path, which may be a mechanism for treating retinal edema with bevacizumab.
Objective To evaluate the therapeutic effect of intravitreal injection with bevacizumab (Avastin) (IVB)combined with extra panretinal photocoagulation (E-PRP) for highrisk proliferative diabetic retinopathy (PDR).Methods A total of 57 eyes of 53 patients with highrisk PDR underwent intravitreal injection combined with E-PRP. The examinations of vision acuity, intraocular pressure, iris fluorescein angiography (IFA),fundus photos and fundus fluorescein angiography (FFA) were performed on all of the patients before and 1,2,3,and 6 months after the treatment; the results of the examinations before and after the treatment were compared and analyzed.The average follow up was 6 months.Results The mean visual acuity was (0.143plusmn;0.072) before the treatment and (0.218plusmn;0.128) 7 days after the tretment; the difference was significant (t=-7.940, Plt;0.05). The mean visual acuity 1,3,and 6 months after E-PRP (0.228plusmn;0.138, 0.223plusmn;0.125,0.220plusmn;0.134, respectively) differed much from that before IVB (Plt;0.05), but not so much from that after IVB (Pgt;0.05).The mean intraocular pressure of 21 eyes which had the neovascularization of pupil margin and iris surface before and 7 days after IVB was (26.632plusmn;2.629) and (19.316plusmn;3.092) mm Hg(1 mm Hg=0.133 kPa), respectively; the difference was significant (t=12.838, Plt;0.05) . The mean intraocular pressure 1,3,and 6 months after E-PRP was (16.947plusmn;2.345),(16.474plusmn;1.611), and (16.421plusmn;4.702) mm Hg, respectively, which differed much from that before and after IVB (Plt;0.05). Neovascularization on the disc and the retinae of 57 eyes were subsided partly, and a significant reduction or disappeared of the area of retinal neovascularization and the blood vessel leakage were observed 7 days after IVB. The neovascularization of pupil margin and iris surface of 21 eyes disappeared, and the IFA leakage decreased. The results of FFA 2 months after E-PRP showed that the one-off efficiency of E-PRP was 68.4%;12 eyes (21.1%) needed an additional laser, in which 6 eyes (10.5%) underwent vitreous surgery. Conclusion IVB combined with E-PRP as a treatment for highrisk PDR may improve the regression of retinal neovascularization and the reduction of vascular permeability,and prevent or reduce the complications and improve the therapeutic effect.