RESUMEN
Multidrug resistance protein 4 (MRP4) is an energy-dependent membrane transporter responsible for cellular efflux of a broad range of xenobiotics and physiological substrates. In this trial, we aimed to investigate the coeffects of aging and MRP4 deficiency using gene expression microarray and morphological and electrophysiological analyses of mouse retinas. Mrp4-knockout (null) mice and wild-type (WT) mice were reared in the same conditions to 8-12 weeks (young) or 45-55 weeks (aged). Microarray analysis identified 186 differently expressed genes from the retinas of aged Mrp4-null mice as compared to aged WT mice, and subsequent gene ontology and KEGG pathway analyses showed that differently expressed genes were related to lens, eye development, vision and transcellular barrier functions that are involved in metabolic pathways or viral infection pathways. No significant change in thickness was observed for each retinal layer among young/aged WT mice and young/aged Mrp4-null mice. Moreover, immunohistochemical analyses of retinal cell type did not exhibit an overt change in the cellular morphology or distribution among the four age/genotype groups, and the electroretinogram responses showed no significant differences in the amplitude or the latency between aged WT mice and aged Mrp4-null mice. Aging would be an insufficient stress to cause some damage to the retina in the presence of MRP4 deficiency.
RESUMEN
PURPOSE: Neuromyelitis optica (NMO) is an autoimmune inflammatory disease that predominantly attacks the optic nerve and spinal cord. This study evaluated the effect of administration of human IgG (hIgG) into the caudal vein on optic nerve degeneration in a rodent model of NMO. METHODS: The optic nerves were exposed to AQP4-Ab-positive sera, and the administration of intravenous immunoglobulin (IVIG) was performed immediately, at 7 days (cohort A) or at 7 days and 10 days (cohort B) after exposure to the sera. A reference group, similarly exposed to the serum, was treated with saline. Retinal ganglion cells (RGCs) labeled by the injection of Fluoro-Gold into the superior colliculus were counted in whole-mounted retina. RGCs labeled by the injection of Fluoro-Gold into the superior colliculus were counted in the whole-mounted retina. RESULTS: The number of RGCs 14 days after optic nerve exposure to sera from patients with NMO was 1455 ± 192/mm(2) (n = 7) in cohort A, 1657 ± 192/mm(2) (n = 4) in cohort B, and 981 ± 182/mm(2) (n = 10) in the saline-treated reference group (p < 0.001). Western blotting revealed that the content of neurofilament in the optic nerve of the hIgG-treated group in cohort A was significantly greater than that in the reference group (p = 0.037). CONCLUSIONS: IVIG administration reduced optic nerve degeneration in a rat model of NMO-optic neuritis. IVIG could be used as a treatment in the acute phase of NMO.