Therapeutic effect of Atractylenolide I on Aspergillus fumigatus keratitis by affecting MyD88/ NF-κB pathway and IL-1ß, IL-10 expression.

PURPOSE: Atractylenolide I (AT-I) is a natural sesquiterpene with anti-inflammatory effects. The purpose of this study was to research the anti-inflammatory effect of AT-I on Aspergillus fumigatus(A. fumigatus) keratitis in mice. METHODS: Cytotoxicity test and cell scratch test were used to determine the therapeutic concentrations of corneal infections. In vivo and in vitro studies, mouse cornea and human corneal epithelial cells (HCECs) infected with A. fumigatus were treated with AT-I or dimethyl sulfoxide (DMSO). Then, to analyze the effect of AT-I on inflammatory response, namely neutrophil or macrophage recruitment and the expression of cytokines involving MyD88, NF-κB, interleukin 1ß (IL-1ß) and interleukin 10 (IL-10). To study the effects of the drug, the techniques used include slit-lamp photography, immunofluorescence, myeloperoxidase (MPO) detection, quantitative real-time polymerase chain reaction (QRT-PCR), and western blot. At the same time, in order to explore the combined effect of the drug and natamycin, slit-lamp photographs and clinical scores were used to visually display the disease process. RESULTS: No cytotoxicity was observed under the action of AT-I at a concentration of 800 µM. In mouse models, AT-I significantly suppressed inflammatory responses, reduced neutrophil and macrophage recruitment, and decreased myeloperoxidase levels early in infection. Studies have shown that AT-I may reduce the levels of IL-1ß and IL-10 by inhibiting the MyD88/ NF-κB pathway. The drug combined with natamycin can increase corneal transparency in infected mice. CONCLUSION: AT-I may inhibit MyD88 / NF-κB pathway and the secretion of inflammatory factors IL-1 ß and IL-10 to achieve the therapeutic effect of fungal keratitis.

Nerolidol inhibits the LOX-1 / IL-1ß signaling to protect against the Aspergillus fumigatus keratitis inflammation damage to the cornea.

PURPOSE: Nerolidol, a naturally occurring sesquiterpene has both anti-microbial and anti-inflammatory properties. The current study aims to investigate the antifungal and the anti-inflammatory effects of nerolidol against mouse Aspergillus fumigatus (A. fumigatus) keratitis. METHODS: The minimum inhibitory concentration (MIC) and cytotoxicity tests were used to study the antifungal ability. For in vivo and in vitro studies, the mouse corneas and the human corneal epithelial cells (HCECs) infected with A. fumigatus spores were intervented with nerolidol or phosphate buffer saline (PBS). Thereafter, the effect of the nerolidol on the response against inflammation was analyzed using the following parameters: recruitment of the neutrophils or macrophages and the expression of the lectin-type oxidized low density lipoprotein receptor-1 (LOX-1) and interleukin 1ß (IL-1ß). Techniques used were the slit lamp, immunofluorescence, myeloperoxidase (MPO) detection, quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot. RESULTS: Nerolidol directly inhibits the growth of A. fumigatus. The administration of nerolidol reduced the severity of fungal keratitis with infiltration of fewer inflammatory cells and reduced levels of the LOX-1, as well the anti-inflammatory cytokines such as IL-1ß were reduced compared with the PBS group. Additionally, in vitro studies showed that treatment with nerolidol inhibited the production of the LOX-1 / IL-1ß levels in A. fumigatus stimulated HCECs. CONCLUSION: Nerolidol attenuated the A. fumigatus keratitis inflammatory response by inhibiting the growth of A. fumigatus, reducing the recruitment of the neutrophils and the macrophages, and inhibiting the LOX-1/ IL-1ß signaling.

Chronic h1-antihistamine treatment increases seizure susceptibility after withdrawal by impairing glutamine synthetase.

AIM: To investigate the effect of chronic H1-antihistamine treatment on seizure susceptibility after drug withdrawal in nonepileptic rats and to further study its relation to glutamine synthetase (GS), which is the key enzyme for glutamate metabolism and gamma aminobutyric acid (GABA) synthesis. METHODS: After drug withdrawal from a 2-week treatment with diphenhydramine or pyrilamine, seizure susceptibility was determined by amygdaloid kindling or pentylenetetrazol model; meanwhile, the GS expression or activity was analyzed. The glutamine, glutamate, and GABA contents were measured by high-performance liquid chromatography. RESULTS: Seizure susceptibility significantly increased in amygdaloid kindling and pentylenetetrazol model 10 days after drug withdrawal from a 2-week treatment with H1-antihistamines. Meanwhile, GS activity and expression in the cortex or hippocampus decreased simultaneously with a marked decline of glutamine and GABA content. Comparable inhibition of GS activity by methionine sulfoximine was also sufficient to increase the susceptibility, while supplementation with glutamine reversed the high susceptibility 10 days after diphenhydramine withdrawal. Moreover, the seizure susceptibility increased 10 days after diphenhydramine withdrawal in wild-type mice but not in histidine decarboxylase knockout mice, which lack histamine. CONCLUSIONS: Chronic H1-antihistamine treatment produces long-lasting increase in seizure susceptibility in nonepileptic rodents after drug withdrawal and its mechanism involves impairment of GS through blocking the action of histamine.