1. Alpha-Melanocyte-Stimulating Hormone Maintains Retinal Homeostasis after Ischemia/Reperfusion.
- Author
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Ng TF, Cho JY, Zhao JL, Gardiner JR, Wang ES, Leung E, Xu Z, Fineman SL, Lituchy M, Lo AC, and Taylor AW
- Subjects
- Animals, Mice, Disease Models, Animal, Ependymoglial Cells metabolism, Ependymoglial Cells drug effects, Ependymoglial Cells pathology, Mice, Inbred C57BL, Microglia metabolism, Microglia drug effects, Retinal Degeneration metabolism, Retinal Degeneration pathology, Retinal Degeneration drug therapy, alpha-MSH pharmacology, alpha-MSH metabolism, Apoptosis drug effects, Homeostasis drug effects, Reperfusion Injury metabolism, Reperfusion Injury pathology, Retina metabolism, Retina drug effects, Retina pathology, Retinal Ganglion Cells metabolism, Retinal Ganglion Cells drug effects, Retinal Ganglion Cells pathology
- Abstract
Augmenting the natural melanocortin pathway in mouse eyes with uveitis or diabetes protects the retinas from degeneration. The retinal cells are protected from oxidative and apoptotic signals of death. Therefore, we investigated the effects of a therapeutic application of the melanocortin alpha-melanocyte-stimulating hormone (α-MSH) on an ischemia and reperfusion (I/R) model of retinal degenerative disease. Eyes were subjected to an I/R procedure and were treated with α-MSH. Retinal sections were histopathologically scored. Also, the retinal sections were immunostained for viable ganglion cells, activated Muller cells, microglial cells, and apoptosis. The I/R caused retinal deformation and ganglion cell loss that was significantly reduced in I/R eyes treated with α-MSH. While α-MSH treatment marginally reduced the number of GFAP-positive Muller cells, it significantly suppressed the density of Iba1-positive microglial cells in the I/R retinas. Within one hour after I/R, there was apoptosis in the ganglion cell layer, and by 48 h, there was apoptosis in all layers of the neuroretina. The α-MSH treatment significantly reduced and delayed the onset of apoptosis in the retinas of I/R eyes. The results demonstrate that therapeutically augmenting the melanocortin pathways preserves retinal structure and cell survival in eyes with progressive neuroretinal degenerative disease.
- Published
- 2024
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