الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 162 |  |  |
| | | from | 162 | | |
Abstract
Blue light induced retinal injury has become a very common problem due to over exposure to blue light emitting sources such as LED lights, computers, mobile phones and other devices.
Stromal vascular fraction cells (SVFCs) are adipose tissue derived cells and are formed of mesenchymal stem cells, smooth muscle cells, endothelial precursor cells, preadipocytes, macrophages and pericytes. They have anti- inflammatory, angiogenic and immunomodulatory effects with differentiation capacity.
This study was concerned with determination of physical, behavioral, biochemical, histological and immunohistochemical changes in adult male albino rats exposed to blue light and studying the possible ameliorating effect of SVFCs and the possible involved mechanisms.
In this study, 40 adult male albino rats were divided into 4 groups:
At the first 2 weeks of the experiment: all groups are kept in complete darkness. The subsequent 4 weeks: the control and SVFCs-control groups were kept also in darkness but BL-group and BL-SVFCs group were subjected to blue light. At the end of sixth week, control group and BL-group were injected intravenously by 1 ml of phosphate buffered saline (PBS) and the SVFCs-control and BL-SVFCs groups were injected intravenously by 1ml SVFCs (1x106 cells/ ml). Then all groups are kept in complete darkness for another 4 weeks.
The results of the current study revealed that:
• The mean levels of feed intake and weight gain in rats: The BL-group showed a significant decrease in feed intake and weight gain compared
to both control groups. The BL-SVFCs group showed a significant increase in both feed intake and weight gain compared to BL-group and both control groups.
• The percentage of rats in the BL group who responded positively to the eye blink response test was significantly lower than in the control groups. The number of responding rats, however, was significantly higher in the BL-SVFCs group than in the BL-group overall. However, they saw a far larger decline than the control groups did.
• Oxidative stress indicators in the retina: there was a substantial rise in malondialdehyde (MDA) levels in the retinas of the BL-group compared to the controls, indicating a failure of the retina’s antioxidant systems (significant decrease in TAC compared to control groups). Retinal tissue treated with SVFCs showed reduced oxidative stress (significantly lower MDA compared to the BL-group) and activated antioxidant mechanisms (significant increase in TAC compared to BL- group).
• Retinal levels of TLR-4, MTD-88 and NF-κB: BL-group showed a significant rise in TLR-4, MYD-88 and NF-κB levels compared to control groups. In BL-SVFCs group, these parameters decreased compared to BL-group. Meanwhile, they still had a significant rise compared to control groups.
• In Hematoxylin and Eosin-stained sections: BL- group showed marked morphological changes in the form of significantly decreased retinal thickness with loss of normal retinal architecture. In addition, there were photoreceptors disorganization, neuronal loss and degeneration in the outer nuclear layer, inner nuclear layer and ganglion cell layer.
Outer plexiform layer loss, highly vacuolated inner plexiform layer and disrupted outer limiting membrane. Administration of SVFCs in BL- SVFCs group resulted in partial restoration of normal retinal thickness, retinal layers and photoreceptors’ organization.
• In toluidine blue stained sections: In BL-group, the H&E results were verified. Moreover, there was separation between pigmented epithelium and photoreceptors and frequently observed Müller cells. Treatment with SVFCs in BL-SVFCs group revealed restoration of most of retinal layers and more frequently Müller cells.
• Activated caspase-3 immunohistochemical study showed significant increase in the number of immune-positive cells in BL- group compared to control groups. However, SVFCs administration caused significant decrease in the number of immune-positive cells compared to BL-group.
• GFAP immunohistochemical study showed significant increase in GFAP immune-reactivity (indicating Astrocytes and Müller cells) in BL-group compared to both control groups and more increase in GFAP immune-reactivity in BL-SVFCs group compared to all other groups that was confirmed statistically.
• Transmission electron microscopic study showed retinal pigmented epithelium with degenerated mitochondria, decreased melanosome content and disrupted microvilli, distorted outer and inner segments of photoreceptors and degenerated photoreceptor cells, amacrine cells, horizontal cells, bipolar cells and ganglion cells in BL-group. BL- SVFCs revealed improvement of most of these degenerative changes.