Background Acute respiratory distress syndrome (ARDS) is one of the most common complications in coronavirus disease 2019 patients suffering from acute lung injury (ALI). In ARDS, marked distortion of pulmonary architecture has been reported. The pulmonary lesions in ARDS include hemodynamic derangements (such as alveolar edema and hemorrhage), vascular and bronchiolar damage, interstitial inflammatory cellular aggregations, and eventually fibrosis. Bleomycin induces ARDS-representative pulmonary damage in mice and rats; therefore, we used bleomycin model mice in our study. Recently, Toll-like receptor 9 (TLR9) was implicated in the development of ARDS and ALI.
Methods In this study, we evaluated the efficiency of a TLR9 blocker (ODN2088) on bleomycin-induced pulmonary damage. We measured the apoptosis rate, inflammatory reaction, and fibroplasia in bleomycin- and bleomycin + ODN2088-treated mice.
Results Our results showed a significant amelioration in bleomycin-induced damage to pulmonary architecture following ODN2088 treatment. A marked decrease in pulmonary epithelial and endothelial apoptosis rate as measured by cleaved caspase-3 expression, inflammatory reaction as indicated by tumor necrosis factor α expression, and pulmonary fibrosis as demonstrated by Van Gieson staining and α-smooth muscle actin immunohistochemistry were observed following ODN2088 treatment.
Conclusions All these findings indicate that blocking downstream TLR9 signaling could be beneficial in prevention or mitigation of ARDS through hemodynamic derangements, inflammation, apoptosis, and fibrosis.
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BACKGROUND Pathogenesis of acute respiratory distress syndrome (ARDS) is a controversial issue. Few studies have analyzed the possible role of vascular endothelial growth factor (VEGF) and its receptors in this lesion. METHODS We compared the immunohistochemical expression of VEGF, its receptors (VEGFR1, VEGFR2) and CD68, in normal lungs and lungs with ARDS. Fifty necropsy cases and 12 lung biopsies with ARDS were analyzed. In total, eight cases were in the early stage and 54 cases were in late stage of ARDS.
In addition, the serum level of VEGF165 was also determined. RESULTS In normal lungs, all antibodies marked the endothelial cells (EC) and pneumocytes (PC), except for CD68, which was expressed in the alveolar macrophages. In early ARDS, the intensity of VEGF165 and VEGFR2 decreased in both EC and PC. VEGF121 was absent in PC but its expression increased in bronchial epithelium. VEGFR1 was expressed in the integral PC. In late ARDS, VEGF165 down-regulation was more significant in PC and EC but its intensity increased in hyaline membranes (HM). In some cases, HM were CD68 positive. The serum level of VEGF165 was up-regulated, while VEGF165 intensity in PC decreased and the HM appeared in alveolar spaces. CONCLUSIONS Sporadic positivity of HM for CD68 and decreasing of VEGF165 expression in EC proved that VEGF165 is produced by PC, destroyed macrophages, and extravasated serum.
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Microscopic and ultrastructural examination on the brain revealed nuclear chromatin clumping of the neuron in mice exposed to the magnetic field for more than four hours. The change was proportional to the exposed time and more prominent in the cerebral cortex. An immunohistochemical study for amyloid precursor protein (APP) was also performed. There was an increased expression of APP in the neuronal cytoplasm of the mouse brain exposed to the magnetic field for 4 hours or more. But the reaction was not proportional to the exposure time and reactive neuron was diffusely distributed through the whole brain. Anti-APP antibody reactivity was not correlated with the chromatin clumping. The mechanism of APP induction was postulated as stress-induced APP-gene induction, and the role of APP was presumed to protect the neuron against hazardous environment.
PURPOSE: To investigate renal toxicity of high-dose intravenous immunoglobulin(IVIG) in children with Kawasaki disease and idiopathic thrombocytopenic purpura. METHODS: 23 children with Kawasaki disease and 7 children with idiopathic thrombocytopenic purpura who were treated with high-dose IVIG(2 g/kg) were evaluated for the change of urine output, blood urea nitrogen(BUN), serum creatinine(Scr), creatinine clearance(Ccr), tubular reabsorption of phosphorus(TRP), fractional excretion of sodium(FENa), 24hour urine b2-microg1obuin/creatinine(b2MG/cr) ratio and urine microalbumin/creatinine(MA/cr) ratio at post-IVIG 1 and 3 day. RESULTS: There was no significant change of urine output, BUN, Scr, Ccr, TRP, 24hour urine b2MG/cr and MA/cr ratio after high-dose IVIG treatment. Transient increase of FENa at post-IVIG 1 day was the only significant change. CONCLUSION There was no significant renal toxicity of high-dose IVIG in children with Kawasaki disease and idiopathic thrombocytopenic purpura who had normal renal function.