Protective Effects of Anthocyanins Extracted from Vaccinium Uliginosum on 661W Cells Against Microwave-Induced Retinal Damage.

OBJECTIVE: To study the protective effect of anthocyanins extracted from Vaccinium Uliginosum (VU) on retinal 661W cells against microwave radiation induced retinal injury. METHODS: 661W cells were divided into 6 groups, including control, model [661W cells radiated by microwave (30 mW/cm2, 1 h)] and VU groups [661W cells pretreated with anthocyanins extracted from VU (25, 50, 100 and 200 µg/mL, respectively) for 48 h, and radiated by microwave 30 mW/cm2, 1 h]. After treatment with different interventions, the cell apoptosis index (AI) was determined using Heochst staining; contents of malonaldehyde (MDA), glutataione (GSH), and activity of superoxide dismutase (SOD) were measured. mRNA expressions of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase 1(HO-1) were detected by real time quantitative polymerase chain reaction, and the expression of HO-1 protein was examined by Western blot analysis. Nucleus and cytoplasm were separated and Nrf2 protein expression was further verified by Western blot analysis. RESULTS: There was significant difference in AI among the groups (F=322.83, P<;0.05). Compared with the control group, AI was significantly higher in the model group and was lower in 4 VU-pretreated groups (P<;0.05). Linear regression analysis showed the decline of AI was in a dose-dependent manner with VU treatment (r=0.8419, P<;0.05). The MDA and GSH contents of 661W cells in VU-treated groups were significantly lower than the model group (P<;0.05). Compared with the model group, the SOD activity in the VU-treated groups (50, 100 and 200 µg/mL) was significantly higher (all P<;0.05). The Nrf2 and HO-1 mRNA expressions were slightly increased after irradiation, and obviously increased in 100 µg/mL VU-treated group. After irradiation, the relative expressions of HO-1 and Nrf2 proteins in nucleus were slightly increased (P<;0.05), and the changes in cytoplasm were not obvious, whereas it was significantly increased in both nucleus and cytoplasm in the VU treatment groups. CONCLUSIONS: Anthocyanins extracted from VU could reduce apoptosis, stabilize cell membrane, and alleviate oxidant injury of mouse retinal photoreceptor 661W cells. The mechanism might be through activating Nrf2/HO-1 signal pathway and inducing HO-1 transcription and translation.

Recombination and identification of human alpha B-crystallin.

AIM: To recombine the human alpha B-crystallin (αB-crystallin) using gene cloning technology and prokaryotic expression vector and confirm the biological activity of recombinant human αB-crystallin. METHODS: Cloning the human αB-crystallin cDNA according to the nucleotide sequence of the human αB-crystallin, constructing the pET-28/CRYAB prokaryotic expression plasmid by restriction enzyme digestion method, and stably expressing transformed into the Escherichia coli (E. coli) DH5 alpha. The recombinant human αB-crystallin was purified by Q sepharose. By enzyme digestion analysis, Western blotting and sequencing, the recombinant human αB-crystallin was identified and the activity of its molecular protein was detected. RESULTS: Compared with the gene bank (GeneBank), the cloned human sequence of human αB-crystallin cDNA has the same open reading frame. Identification and sequencing of the cloned human αB-crystallin cDNA in prokaryotic expression vector confirmed the full length sequence, and the vector was constructed successfully. The E. coli containing plasmid pET-28/CRYAB induced by isopropyl-ß-D-thiogalactoside successfully expressed the human αB-crystallin. Insulin confirmed that the recombinant human αB-crystallin has a molecular chaperone activity. CONCLUSION: The prokaryotic expression vector pET-28/CRYAB of recombinant human αB-crystallin is successfully constructed, and the recombinant human αB-crystallin with molecular chaperone activity is obtained, which lay a foundation for the research and application of the recombinant human αB-crystallin and its chaperone activity.

[Alternative splicing of vascular endothelial growth factor A and ocular neovascularization].

Ocular neovascularization is the primary cause of blindness in a wide range of ocular diseases. The vascular endothelial growth factor A (VEGF-A) is the key factor involved in ocular angiogenesis, which can cause eye diseases through the development of pathological angiogenesis and increase of vascular permeability. There are two families of VEGF-A isoforms formed by alternative splicing, the angiogenic VEGF-A family (VEGF(xxx)), known to contribute to ocular neovascularization, and the anti-angiogenic VEGF-A family (VEGF(xxx)b), which is found in normal ocular tissues but downregulated in human diabetic retinopathy. The first member of the VEGF(xxx)b family to be isolated was VEGF(165)b. It can significantly reduce preretinal neovascularization without inhibition of physiological intraretinal angiogenesis. As the studies on the VEGF(xxx)b family proceed more deeply, controlling the balance of VEGF(xxx) to VEGF(xxx)b isoforms may be therapeutically valuable in the treatment of angiogenic eye diseases such as diabetic retinopathy and age-related macular degeneration.