ABSTRACT
AIM: To investigate the occurrence of chronic photodamage in the cone-based retina, following long-term exposure to a 650-nm semiconductor laser (power: 2 mW). METHODS: Chickens fed for 1mo under natural light after hatching were irradiated with 650-nm laser light at different times each day. Fifteen animals were included in each group. Group A was a control group, irradiated with natural light during the entire study. Group B was irradiated with laser for 3 min/d. Group C was irradiated with laser for 6 min/d. Group D was irradiated with laser for 30 min/d. The duration of the light experiment was 6mo. We obtained data at 1, 3, and 6mo, including measuring the retinal thickness in vivo using optical coherence tomography, hematoxylin and eosin staining, TUNEL assay, apoptosis staining, malondialdehyde (MDA) content, superoxide dismutase (SOD) activity, and Western blotting to detect changes in L/M opsins and rhodopsin. RESULTS: At 1mo, the MDA content in Group D was higher than that observed in Group A (P=0.019). At 3mo the MDA content in Groups C and D was higher than that reported in Group A (P=0.026, 0.003). At 6mo, the MDA content in Groups B, C, and D was higher than that observed in Group A (P=0.038, 0.032, 0.000, respectively). There was no difference in SOD activity, and L/M opsin and rhodopsin content between the groups at 1 and 3mo. The SOD activity in group D was significantly decreased at 6mo (P=0.000), as was the content of rhodopsin. There was no significant reduction observed in retinal thickness, abnormal cell arrangement, and positive staining of TUNEL in the groups during the 6-month study period. CONCLUSION: Irradiation using a 650 nm semiconductor laser (power: 2 mW) for 6min per day over 6mo do not cause photodamage. Similarly, a 3-month exposure of 30min per day do not cause damage. However, irradiation for 6mo resulted in a significant increase in the content of free radicals and a decrease in the content of rhodopsin in the retina, suggesting the presence of photodamage.
ABSTRACT
AIM: To investigate whether umbilical cord human mesenchymal stem cell (UC-MSC) was able to differentiate into neural stem cell and neuron in vitro. METHODS: The umbilical cords were obtained from pregnant women with their written consent and the approval of the Clinic Ethnics Committee. UC-MSC were isolated by adherent culture in the medium contains 20% fetal bovine serum (FBS), then they were maintained in the medium contain 10% FBS and induced to neural cells in neural differentiation medium. We investigated whether UC-MSC was able to differentiate into neural stem cell and neuron in vitro by using flow cytometry, reverse transcriptase-polymerase chain reaction (RT-PCR) and immunofluorescence (IF) analyzes. RESULTS: A substantial number of UC-MSC was harvested using the tissue explants adherent method at about 2wk. Flow cytometric study revealed that these cells expressed common markers of MSCs, such as CD105 (SH2), CD73 (SH3) and CD90. After induction of differentiation of neural stem cells, the cells began to form clusters; RT-PCR and IF showed that the neuron specific enolase (NSE) and neurogenic differentiation 1-positive cells reached 87.3%±14.7% and 72.6%±11.8%, respectively. Cells showed neuronal cell differentiation after induced, including neuron-like protrusions, plump cell body, obviously and stronger refraction. RT-PCR and IF analysis showed that microtubule-associated protein 2 (MAP2) and nuclear factor-M-positive cells reached 43.1%±10.3% and 69.4%±19.5%, respectively. CONCLUSION: Human umbilical cord derived MSCs can be cultured and proliferated in vitro and differentiate into neural stem cells, which may be a valuable source for cell therapy of neurodegenerative eye diseases.
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AIM: To investigate the visual function and the relationship with vision-related quality of life (VRQOL) after macular hole repair surgery. METHODS: Prospective case series. Thirty-six consecutive eyes in 36 patients who underwent pars plana vitrectomy (PPV) and internal limiting membrane (ILM) peeling were included. The 25-item National Eye Institute Visual Function Questionnaire (VFQ-25) was answered by the participants before and 3 and 12mo after operation. Follow-up visits examinations included best-corrected visual acuity (BCVA), clinical examination, and central macular thickness (CMT) measured by optical coherence tomography (OCT). RESULTS: Macular-hole closure was achieved in 35 of 36 eyes (97.2%). At baseline and months 3 and 12, the logMAR BCVAs (mean±SD) were 1.15±0.47, 0.68±0.53 (P<0.0001 versus baseline), and 0.55±0.49 (P<0.001 versus baseline, P =0.273 versus month 3), respectively; the CMTs (µm) were 330±81, 244±62 (P<0.001 versus baseline), and 225±58 (P<0.001 versus baseline, P=0.222 versus month 3), respectively; the median preoperative VFQ-25 composite score of 73.50 (63.92-81.13) increased postoperatively to 85.50 (80.04-89.63) at 3mo (P<0.001) and 86.73(82.50-89.63) at 12mo (P<0.001) respectively. The improved BCVA was correlated with improvements in five subscales (r=-0.605 to -0.336, P<0.001 to P=0.046) at 12mo. CONCLUSION: PPV with ILM peeling improved anatomic outcome, visual function, and VRQOL. The improved BCVA was an important factor related to the improved VRQOL.
ABSTRACT
AIM: To observe the effects of intravitreal injections of different concentrations of human umbilical mesenchymal stem cells on retinopathy in rats with diabetes mellitus. METHODS: Healthy and adult male Sprague-Dawley (SD) rats were randomly assigned to a normal control group (group A), a diabetic retinopathy (DR) blank control group (group B), a high-concentration transplantation group (group C), a low-concentration transplantation group (group D) and a placebo transplantation group (group E). The expression of nerve growth factor (NGF) protein in the retinal layers was detected by immunohistochemical staining at 2, 4, 6 and 8wk. RESULTS: The expression of NGF was positive in group A and most positive in the retinal ganglion cell layer. In groups B and E, the expression of NGF was positive 2wk after transplantation and showed an increase in all layers. However, the level of expression had decreased in all layers at 4wk and was significantly reduced at 8wk. In groups C and D, the expression of NGF had increased at 2wk and continued to increase up to 8wk. The level of expression in group C was much higher than that in group D. CONCLUSION: DR can be improved by intravitreal injection of human umbilical mesenchymal stem cells. High concentrations of human umbilical mesenchymal stem cells confer a better protective effect on DR than low concentrations.
