ABSTRACT
Objective:To investigate the effect of heat shock protein B8 (HspB8) downregulation on retinal ganglion cell (RGC) and retinal function in the mice model of optic nerve injury (ONC).Methods:Adeno-Associated Virus (AAV) 2 AAV2-shHspB8-GFP was constructed to knockdown HspB8. 66 adult male C57/BL6 mice were randomly divided into the control group, the ONC group, the AAV2-shHspB8 group, the ONC+AAV2-shHspB8 group, and the ONC+AAV2-GFP group. There were 10, 20, 16, 10 and 10 mice respectively, and both eyes were used as experimental eyes. Western blot was used to evaluate the expression of HspB8 on day 3 and 7 after ONC. By GFP immunofluorescence staining, the efficacy of AAV2-shHspB8-GFP transfer was accessed. Moreover, it was possible to identify functional and RGC survival differences between groups by optomotor response (OMR), dark adapted full-field flash electroretinogram (ff-ERG), oscillatory potentials (OPs), photopic negative response (PhNR) and retinal flat-mount RGC counting 5 days after ONC. Comparisons between two groups were made using Mann-Whitney U test, unpaired t-test, unpaired t-test with Welch’s correction, one-way ANOVA, and Bonferroni t test. Results:Compared with the control group, the expression of HSPB8 protein in the retina of mice in ONC3 group was significantly increased, and the difference was statistically significant ( F=43.63, P<0.01). Compared with the control group, the ONC group showed obviously lower visual acuity ( P<0.01), lower a-wave, b-wave, OPs, PhNR amplitude, longer b-wave latency ( P<0.05), and the survival rates of RGC in ONC3 group, ONC5 group and ONC7 group decreased in a time-dependent manner( F=384.90, P<0.01). Transfection of AAV2 efficiency was highest on 4 weeks after IVT. Besides, there was no significant differences between the control group and the AAV2-shHspB8 group on visual acuity, ff-ERG, OPs, PhNR and RGC survival ( P>0.05). In comparison of the control group, we found that RGC survival of the ONC5+AAV2-shHspB8 group was significantly elevated ( F=10.62, P<0.01). Conclusions:Expression of HspB8 on the retina can be induced by ONC. The investigation of RGC counting, visual acuity, and ff-ERG revealed that optic nerve injury destructed functionality of mice retina and resulted to RGC death ultimately. The Most crucial finding of this research is that HspB8 knockdown had a neuroprotective effect in RGC after ONC.
ABSTRACT
Objective To evaluate the correlation of oxygen saturation of retinal vessels and diabetic retinopathy (DR) stages or HbA1c level in patients with DR. Methods Cross sectional study. A total of 102 patients (102 eyes) with DR and 20 age-matched healthy controls (20 eyes) (normal control group) were enrolled in this study. DR patients were divided into mild and moderate non-proliferative DR (NPDR) group (55 patients), severe NPDR group (26 patients) and proliferative DR (PDR) group (21 patients). DR patients were also divided into 3 groups according to the HbA1c level including HbA1c>9%(8 patients), HbA1c 7%–9%(33 patients) and HbA1c9%group were significantly higher than that in HbA1c 7%–9%group and HbA1c9%, HbA1c 7%0.05). Conclusions The retinal artery and vein oxygen saturation in DR patients are related to the DR stages. Severe NPDR patients show the highest retinal artery oxygen saturation as well as biggest difference between retinal artery and vein oxygen saturation. There is also a trend that retinal vein oxygen saturation increases with higher DR stages. In addition, there is a positive correlation between the levels of HbA1c and retinal vessel oxygen saturation.