| Objective To investigate the effect of cyclo-peptide CHSDGIC derived frompituitary adenylate cyclase activating polypeptide (PACAP) on preventing apoptosisof Rat retinal ganglion cell line (RGC-5) induced by ultraviolet light B(UVB). Thestudy will provide experimental base for provention and treatment of RGC cytopathyof CHSDGIC.Methods Transformed rat RGC-5cells were cultured in high glucose DMEMconventionally, and then exposed to UVB light to induce apoptosis.(1) Theexpressions of PAC1receptor in RGC-5under normal condition and exposure toUVB were measured by Western-blot assay.(2) RGC-5cells were randomly assignedto4experimental groups receiving CHSDGICwith different concentration (1μmol/L、10μmol/L、100μmol/L、1000μmol/L) and a control group receiving0.9%NaCl. AllRGC-5cells in the5groups were exposed to UVB light for3min.24h later, thesurvival of RGC-5cells was detected by Cell Counting Kit-8(CCK-8) assay; and flowcytometric analysis of RGC-5cell apoptosis with treatments of UVB light withoutCHSDGIC or UVB light with10μmol/L CHSDGIC was carried out.Results (1) PAC1receptor was expressed in RGC-5cells under normal condition orexposure to UVB light.(2) The survival rates of RGC-5cells receiving1μmol/L,10μmol/L,100μmol/L, and1000μmol/Lof CHSDGIC were (34.00±1.07)%,(55.20±2.23)%,(36.69±1.96)%, and (42.93±1.91)%, respectively, which weresignificantly higher than that in control group (24.62±1.72)%(all P<0.05).(3)Annexin V and PI assays showed RGC-5cells treated with UVB light showed asignificant increase in the ratio of apoptotic cells(37.40±2.40)%compared with thenormal group(5.43±1.02)%, and incubation with of10μmol/L CHSDGICsignificantly reduced the increase of the ratio of apoptotic cells(15.30±1.10)%treatedwith UVB light irradiation (all P<0.05).Conclusion There are PACAP-specific PAC1receptors in the RGC-5cells.Cyclo-peptide CHSDGIC could protect RGC-5cells against the apoptosis induced by UVB light. |
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