ABSTRACT
Objective:To observe whether there was a chronic light damage after the irradiation of 650 nm semiconductor laser (power 2 mW) in chicken cone-rich-retina and discuss the safety of this laser for retina.Methods:Sixty 1-month-old chicken reared under natural light were divided into a normal control group, an irradiation 3-min group, an irradiation 6-min group and an irradiation 30-min group by using a random number table and 15 for each group.The chicken eyes were irradiated with 650 nm laser for different duration according to a grouping.Relative retina area was measured with optical coherence tomography (OCT) at 1 month (2-month-old chicken), 3 months (4-month-old chicken) and 6 months (7-month-old chicken) after laser irradiation.Chickens were sacrificed by overdose anesthesia and the histopathology of chiken retina was examined by hematoxylin-eosin staining.The apoptosis of the retinal cells was evaluated by TUNEL staining.Chicken retinal homogenate was prepared, and the content of malondialdehyde and activity of superoxide dismutase (SOD) in the retina were detected by TBA method and NBT method, respectively.Western blot was employed to detect the expression of L/M opsin and rhodopsin in the retina.The use and care of the animals complied with Regulations for the Administration of Affair Concerning Experimental Animals by State Science and Technology Commission.Results:In 2-month-old chicken, the molar concentration of malondialdehyde in retina was significantly higher in the irradiation 30-min group compared with the normal control group ( P<0.05). In 4-month-old chicken, the molar concentration of malondialdehyde was statistically higher in the irradiation 6-min group and the irradiation 30-min group in comparison with the normal control group ( P=0.026, 0.003). In 7-month-old chicken, the concentrations of retinal malondialdehyde in the irradiation 3-min group, irradiation 6-min group and irradiation 30-min group were statistically higher than those of the normal control group( P=0.038, 0.032, <0.01). In 7-month-old chicken, the SOD activity and the relative expression of rhodopsin in the retina of the irradiation 30-min group were statistically reduced incomparison with the normal control group (SOD: [140.20±5.99][nmol/s·mg] vs.[160.57±3.13][nmol/s·mg]); Rhodopsin: 0.392±0.065 vs.0.566±0.072) (both at P<0.05). OCT showed that there was no significant difference in relative retinal area within 6 months among the four groups.Histopathological examination showed that the thickness of the retina in each irradiation group was close to the normal control group.TUNEL staining showed that the retinal cells were regularly arranged, and no TUNEL positive staining cells were found in all of the groups. Conclusions:Irradiation of a 650 nm semiconductor laser (2 mW) in chicken's eyes for 6 minutes is safe for retina within 6 months.The lasser irradiation 30 minutes for 6 months results in an increase of free radical content in the retina and a decrease in rhodopsin, suggesting the presence of photo damage.
ABSTRACT
Objective To build the lentiviral vectors of pigment epithelial derived factor (PEDF) gene,and investigate their expression in human umbilical cord mesenchymal stem cells (hUCMSCs).Methods The PEDF lentiviral vectors (LV-PEDF) were built by DNA recombination and confirmed by DNA sequencing.hUCMSCs were transfected by LV-PEDF with MOI 10,30,50,respectively.The transfection efficiency was observed under fluorescence microscope.Cell immunofluorescence,immunocytochemistry and real-time PCR methods were used for detecting the expression of PEDF and VEGF.Results The PEDF cDNA was sub-cloned into pCDH-CMV-MCS-EF 1-copGFP vector successfully.DNA sequencing analysis confirmed that PEDF gene sequence was exactly the same with that reported in GenBank.pCDH-PEDF infected cells could show green fluorescence under fluorescence microscope.The transfection efficiency was 72.1％ in PEDF-MSCs.Immunofluorescence and immunochemical staining confirmed that PEDF protein was overexpressed in hUCMSCs.The relative expression of PEDF mRNA in experimental group and control group was (0.170±0.028) and (0.015 ± 0.007) respectively by RT-PCR,the difference was statistically significant (P＜0.00 1).The relative expression levels of VEGF mRNA in the two groups were (0.265 ± 0.022) and (0.285 ± 0.049),respectively,with no significant difference (P＞0.05).Conclusions We successfully built a lentivius vector carrying PEDF gene and obtained hUCMSCs with overexpressed PEDF.
ABSTRACT
Background Retina fixed flat-mount perfused by Evans blue (EB) is a common method for the evaluation of blood-retinal barrier (BRB).However,previous method is inconvenient for some laboratories because the retinal specimen can not be observed by gereral microscope rather than confocal laser scanning microscope after the fixation.Objective This study was to modify the preparing way of flat-mounted retina in order to obtain transparent specimen for the observation of rat retinal vessels and the evaluation of leakage under the ordinary fluorescence microscope.Methods Forty male SD rats were divided into the control group,diabetes mellitus (DM) 1-month group,DM 3-month group and DM 6-month group according to the random number table.Streptozotocinum (STZ) of 2％ dissolved in 0.05 mmol/L sodium citrate-hydrochloric acid buffer was intraperitoneally injected in SD rats to establish DM models,and the equal volume of solvent was injected in the same way in the control rats.One month,three months and six months after injection,EB of 30 g/L was injected via rat femoral vein in the dose of 45 mg/kg.Fifteen minutes after injection of EB,the rats were sacrificed and the retinas were isolated and cut radially to prepare the flat-mounted retinas in PBS immediately and then were dried till the specimens were transparent.The specimens were examined under the fluorescence microscope.The percentage of EB leakage was quantitatively calculated by IPP 6.0 software.All procedures were performed following approval of the institutional animal care and use committee of Tianjin Medical University.Results The retina morphology was normal in the control group,and EB filled the vessels,exhibiting the red fluorescence under the fluorescence microscope.Compared with the control group,retinal background fluorescence was enhanced slightly in the DM 1-month group,and focal leakage of the EB from capillaries and focal dilated vessels were found in the DM 3-month group,further,vascular caliber inequality,retinal hypoperfusion area and a larger number of hyperfluorescence areas were seen in the DM 6-month group.The percentage of leakage area was (0.05 ±0.02) ％,(0.27 ±0.06) ％,(1.17 ±0.18)％ and (4.77 ±0.66)％ in the control group,DM 1-month group,DM 3-month group and DM 6-month group,respectively,showing a significant difference among the four groups (F =795.800,P＜0.001),and the leakage area was obviously larger in the DM 3-month group and DM 6-month group than that in thecontrol group (q'=10.338,q'=43.475,both at P＜0.001).Conclusions Modified EB-perfused retinal wholemount method is easy and helpful for clear visualization of retinal vessel leakage induced by BRB breakdown in the diabetic rats under the common fluorescence microscope.