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| Author(s): |
Ana Lucia Borges Shimada
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Conjunto das Químicas (IQ e FCF) (CQ/DBDCQ) |
| Defense date: | 2011-04-08 |
| Examining board members: |
Sandra Helena Poliselli Farsky;
Simone Marques Bolonheis de Campos;
Adriana Lino dos Santos Franco
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| Advisor: | Sandra Helena Poliselli Farsky |
| Abstract | |
Hydroquinone (HQ) is a phenolic compound of natural or anthropogenic source, also found in high concentrations in cigarette, as well as benzene´s metabolite. Our research group has demonstrated that exposure to HQ impairs in vivo inflammatory response. Following these investigations, this work aimed to study the effects of in vivo exposure to HQ on tracheal tissue and alveolar macrophages (MΦs) activities. For this purpose, male Swiss mice were systemically (aerolised) exposed to 25ppm HQ (1.5 mg/60mL/1h; 5 days) or vehicle (saline ethanol solution, 1:20). Concentrations of inflammatory mediators (interleukin (IL) IL-1β, IL- 6, IL-10, IL-4, IL-12 tumor necrosis factor-α (TNF-α ) or monocyte chemoattractant protein (MCP-1); (enzyme immune assay, ELISA)) and nitric oxide (NO; Griess reaction) were quantified in bronchoalveolar lavage (BAL) at baseline or 3 hours after inflammatory stimulus (in vivo LPS, 100µL/mL; 10min); in the supernatant of cultured alveolar macrophages (MΦs) or trachea obtained from animals and subsequently in vitro stimulated (MΦs: 5µg/mL of LPS plus 10ng/mL IFN-γ; trachea: 1µg/mL LPS; 24 hours). Phagocytic and fungicidal activities (light microscopy) and expression of receptors involved in phagocytosis (toll-like receptor (TLR, TLR2, TLR4 and dectin-1, flow cytometry) were determined after in vitro incubation of alveolar MΦs with Candida albicans fungus and expression of MyD88 pathway was held in alveolar MΦs (western blot). Quantification of mRNA for MCP-1 (reaction of reverse transcriptase polymerase chain reaction, RT-PCR) was performed in tracheal tissue and cells human monocytic THP-1 were used in in vitro chemotaxis assays (Boyden chamber) using different concentrations of MCP-1. Tracheal reactivity was measured in response to methacholine. The results showed that in vivo HQ exposure reduced the concentration of MCP-1 (54.98% vs. control) and IL-12 (51.45% vs. control) in the BAL after inflammation; decreased secretion of MCP-1 by MΦs (basal: 87.96%, LPS+INF-γ: 61.20%) and in tracheal culture after LPS stimulation (79.77% vs. control). In the latter tissue, the MCP-1 protein content was dependent on impaired gene expression. Concentrations of MCP-1 similar to those detected in the supernatant of tracheal from HQ exposed rats induced smaller migration of THP-1 cells (38.2%) than that evoked by the MCP-1 concentration obtained in trachea supernatants collected from control animals. Tracheas from HQ exposed rats showed hyper reactivity (193.48%), which was reversed by removal of the tracheal epithelium. Additionally, culture of MΦs obtained from HQ exposed rats showed increased phagocytic (percentage of phagocytosis: 36.30%; phagocytosis index: 83.97%) and fungicide activity (68.47%), which were not dependent on changes in the receptors TLR2, TLR4 and dectin-1, but could be due to reduced MyD88 expression. Together, these data point out important alterations on MΦs and trachea after in vivo HQ exposure, which may be crucial for the toxicity observed in these animals that culminates with impaired host defense. (AU) | |
| FAPESP's process: | 09/03964-5 - Characterization of mechanisms of action of in vivo hydroquinone exposure on lung mast cells and macrophages |
| Grantee: | Ana Lucia Borges Shimada |
| Support Opportunities: | Scholarships in Brazil - Master |