| Objective To investigate the function and morphological structure changes of retina after intravitreal injection of human umbilical cord cell-induced neuronal stem cells(h UCMSC-NSCs) and anti-vascular endothelial growth factor(VEGF) monoclonal antibody ranibizumab in experimental diabetic rats, observing the different effects of the two intravitreal injections, and study the potential mechanisms of the human umbilical cord cell-induced neuronal stem cells in DR treatment in the purpose to provide the new drug prevention and treatment programs for early DR.Methods Sixty-three clean male Sprague-Dawley(SD) rats were randomly assigned to normal control group with 13 rats(group A) and diabetic mellitus group(group DM) with 50 rats. The model of diabetic rats was established by injecting with streptozocin(STZ) through enterocoelia, and normal control rats were injected with capacity 0.1mol / L citrate buffer. 4 and 10 weeks later, the flash-electroretinogram(F-ERG) with international standardized 3 items was respectively recorded and the morphological changes of retina at different time after modeling were observed by hematoxylin-eosin(HE) staining and optical microscope. When the DM rats were successfully established, the rats of diabetic group were randomly divided into five groups: rats with DM only(group B), rats injected with phosphate buffered saline(PBS) group(group C), rats intravitreal injection of retinal h UCMSCs-NSCs(group D), rats with intravitreal injection of ranibizumab(group E) and 9 rats for each group. Group A and group B received no further treatment. The F-ERG with international standardized 3 items was respectively recorded from all the rats before experiment, 2, 4, 6 weeks after intervention, and each data point was derived from the average of three recordings. The morphological changes of retina at different time after injetion were observed by HE staining and optical microscope.Results 1. F-ERG: No any significant difference was found in F-ERG with international standardized 3 items before experiment(P>0.05). 4 weeks after modeling, whencompared the group A with group DM, only the difference of the total amplitudes of oscillatory potentials(OPs) was statistically significant(P<0.05). 10 weeks after modeling, the differences of the latency and amplitude of b wave of maximum response(Max-R) and the total amplitudes of OPs were statistically significant(P<0.05). 2. 2 and 4 weeks after the intervention, when comparing group D, E with group B, C, we found the amplitude of b wave of rod response(Rod-R), Max-R and the total amplitudes of OPs were significantly increased(P<0.05), and the latency of b wave of Max-R was significantly decreased(P<0.05); between the group D and group E, only the total amplitudes of OPs was statistically significant difference(P<0.05). 6 weeks after the intervention, group D compared with the group B, C, E, the differences of amplitude of b wave of Rod-R, Max-R and the total amplitudes of OPs were significantly increased(P<0.05),and the latency of b wave of Rod-R, Max-R was significantly decreased(P<0.05), and these indicators are gradually towards normal with time going. In addition, comparing group E with group B, C, the differences of various waves were not statistically significant(P>0.05). Besides, when respectively compared the 4 time points within the five experimental groups, the various waves of F-ERG at the 4 time points were not significant statistically significant(P>0.05) in group A. Only the total amplitudes of OPs had statistically significant difference(P<0.05) in group B, C, and with the passage of time the total amplitudes of OPs decreased. In group D, the latency and the amplitude of b wave of Max-R and the total amplitudes of OPs was statistically significant(P<0.05), and the latency of b wave over time decreased, while the amplitude of b wave and the total amplitudes of OPs tended to increase. In group E, the amplitude of b-wave of Rod-R and Max-R, the amplitude of a wave of Max-R, and the total amplitudes of OPs all had statistically significant(P<0.05), and over time the 4 indicators showed a downward trend after the first rise. 3. HE staining: 4 weeks after molding, the organization structure between group A and group DM had no obvious difference. 10 weeks after molding, the each retinal layer and cellular morphology of group A was regular, but each retinal layers were disordered and the amount of cells were reduced in group DM. 2 weeks after theintervention, the cell morphology of retinal layers in group A rats was normal and the internal limiting membrane(ILM) was clear and complete. The number of cells in the retinal layers of group B, C was more reduced than the group A, and the structure was more disorder. When respectively compared the group D and group E with group B, the retinal layers of tissue were no significant differences in the structure. 4 weeks after the intervention, the number of cells in retinal layers of group B, C further reduced when compared with 2 weeks ago, and the cells were arranged in a more disordered structure. The integrity of the ILM further damaged, and the scope of the local thickening increased. It was also found that the retinal vascular endothelial expanded and retinal blood vessels cells proliferated. The structure of each retina layer of Group D, E arranged less disordered, and the number of retinal ganglion cells(RGCs), pericytes and other cells was more than group B, C. No obvious expansive retinal vessels could be found. 6 weeks after the intervention, when compared with group D, the number of RGCs of group B, C, E was sparser, and the nuclei stained deeper, and the nerve fiber layer(NFL) was more flat. The inner nuclear layer(INL) was thinner and the structure was disorder. The outer core layer(ONL) arranged more chaotic and the integrity of the ILM was more damaged.Conclusions 1. The retina in DM rats is improved by intravitreal injection of h UCMSC-NSCs and ranibizumab, and the role of injection of h UCMSC-NSCs is better than injection of ranibizumab. 2. The damage of the retinal structure is later than the damage of the retinal function. Additionally the improvement of retinal morphology is later than the improvement of retinal function after the intervention. 3. The effects of early DR on b wave of F-ERG are greater than the impact on a wave, and the sensitivity to changes in retinal function of amplitude is greater than the latency. |
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