Bruch membrane maintained a pentalaminar structure composed of the RPE basement

Cigarette smoke, which can be considered a strong chemical oxidant, has the strongest epidemiological link with AMD. However, experimental evidence is lacking for injury to the retinal pigmented epithelium, a principal cell type involved in AMD. Critical host factors that protect the RPE from oxidative injury may determine its susceptibility to tissue destruction or modify the intensity of inflammatory Sennidin-B reaction associated with AMD. RPE cell apoptosis and basal deposits, or accumulations of heterogeneous debris in Bruch membrane, are two critical histopathologic changes that are well recognized to occur during the development of early AMD. We used these established changes as endpoints for a study designed to determine if cigarette smoke induces evidence of changes associated with AMD. Mice were exposed to 6 months of cigarette smoke in a chamber that produces emphysema with evidence of oxidative damage. In this manuscript, we explored whether mice exposed to cigarette smoke developed these two cardinal features of early AMD using this protocol. The RPE of 8 mo old mice raised in air appeared healthy with normal basolateral infoldings. Bruch Tiotropium Bromide hydrate membrane maintained a pentalaminar structure composed of the RPE basement membrane, inner collagenous layer, middle elastic layer, outer collagenous layer, and basement membrane. The choriocapillaris endothelium appeared healthy with fenestrations. We chose RPE basolateral infoldings and cytoplasmic vacuoles as indicators of RPE cell degeneration because loss of basal infoldings is a marker of epithelial injury and cytoplasmic vacuoles have been identified in RPE that overlie drusen deposits. Figure 2 also shows an 8 mo old mouse that has been exposed to chronic cigarette smoke exhibiting ultrastructural injury to the RPE-Bruch membrane. The RPE basolateral infoldings are dilated and fewer in number, and contain large cytoplasmic vacuoles. Bruch membrane shows an outer collagenous layer deposit while the choriocapillaris has focal loss of fenestrations. Bruch membrane thickens with aging. We therefore measured Bruch membrane thickness, and found that Bruch membrane was thicker in mice exposed to smoke than those raised in air.

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