Objective To observe the retinal apoptosis of laser-induced retinal injury in mice after bone marrow mesenchymal stem cells transplantation. Methods Green fluorescent protein (GFP) labeled MSCs from C57BL/6 mice were cultured in vitro. A total of 135 C57BL/6 mice were divided into three groups including normal control group (15 mice), injured control group (60 mice) and MSCs treatment group (60 mice). Laser retinal injuries were induced by laser photocoagulation. One day after photocoagulation, 02 ml cell suspension, which contained 1times;106 GFP-MSCs, were injected into the mice in treatment group via tail vein, and the mice in injured control group were given equal volume of phosphate buffer solution. Animal were execute on three, seven, 14 and 21 days following laser damage. Hematoxylin and eosin (HE) staining was performed to assess the changes of injured retinas. The diameters of laser spots and areas with total loss of cells in outer nuclear layer (ONL) were analyzed by image processing software. The apoptosis of retinal cells was examined by terminal-deoxynucleoitidyl transferase mediated nick end labeling (TUNEL) staining. The migration of GFP-MSCs into the retina was observed by fluorescence microscope. Results HE staining showed that the retinal structures were integrated in normal control group. Retinal damages were observed both in injured control group and MSCs treatment group, but milder in the latter. Though the average diameter of area with total loss of cells in ONL of MSCs treatment group was less than the injured control group (t=5.769, P＜0.05), the diameters of laser spots show no difference (t=0.964,P＞0.05) on day three. Both the average diameter of laser spots (t=5.180, 5.417, 2.381) and area with total loss of cells in ONL (t=3.530, 3.224, 3.162) were less in the MSCs treatment group on day seven, 14 and 21 (P＜0.05). TUNEL staining shows that the apoptosis were decreased after MSCs transplantation on day three, seven, 14 and 21 (t=11.142, 7.479, 6.678, 3.953,P＜0.05). No apoptosis was observed in normal control group. Very few GFP-MSCs were observed in the retina at all time-points. They were only seen in the subretinal and choroidal neovascularization occasionally on day seven and 14. Conclusion MSCs transplantation can effectively limit the range of retinal laser damage and inhibit cell apoptosis.
ObjectiveTo investigate the relationship between the pathological and functional changes of the retina and the expression of monocyte chemoattractant protein (MCP)-1 after retinal laser injury in mice. MethodsA total of 116 C57BL/6 mice were randomly divided into the normal group (58 mice) and the injured group (58 mice). Retinal laser injuries were induced by Argon ion laser. At 1, 3, 7 days after laser injury, electroretinogram (ERG) responses were recorded to detect the function of the retina. Hematoxylin and eosin (HE) staining was performed to observe pathological changes. Quantitative real-time polymerase chain reaction (PCR) was performed to detect gene expression of MCP-1. Western blot was used to measure the protein expression of MCP-1. ResultsHE staining showed a progressive damage of the retinal structure. The results of ERG showed that the differences of dark-adaptive a wave (t=6.998, 9.594, 13.778) and b wave (t=12.089, 13.310, 21.989) amplitudes of 1, 3 and 7 day post-injury between normal group and injured group were statistically significant (P=0.000). At 1 day post-injury, the differences of light adaptive b wave amplitudes between the two groups were statistically significant (t=8.844, P=0.000). While the differences of light-adaptive a wave amplitudes were not (t=2.659,P=0.200). At 3, 7 days post-injury, the differences of a (t=3.076, 7.544) and b wave amplitudes (t=10.418, 8.485) between the two groups were statistically significant (P=0.000). In dark-adaptive ERG, the differences of a wave amplitudes between 1 day and 3 days (t=3.773), 1 day and 7 days (t=5.070) and b wave amplitudes between 1 day and 7 days (t=4.762) were statistically significant (P<0.01), while the differences of a wave amplitudes between the 3 days and 7 days (t=1.297) and b wave amplitudes between 1 day and 3 days (t=2.236), 3 day and 7 days (t=2.526) were not significant (P=0.660, 0.120, 0.060). In light-adaptive ERG, the differences of a wave amplitudes between 1 day and 7 days (t=2.992) and b wave amplitudes between 1 day and 3 days (t=3.570), 1day and 7 days (t=4.989) were statistically significant (P<0.05), while the differences of a wave amplitudes between 1 day and 3 days (t=0.516), the 3 days and 7 days (t=2.475) and b wave amplitudes between 3 days and 7 days (t=1.419) were not significant (P=1.000, 0.710, 0.070). Quantitative real-time PCR showed that the differences of MCP-1 gene expression at 1, 3 and 7 day post-injury between normal group and injured group were statistically significant (t=14.329, 16.861, 5.743; P<0.05). Western blot showed that the differences of MCP-1 protein expression at 1, 3 and 7 day post-injury between normal group and injured group were statistically significant (t=75.068, 54.145, 14.653; P<0.05). ConclusionIn the first 7 days after mice retinal laser injury, there are progressive pathological and functional damage of the retina, which might be correlated with MCP-1 expression.