Histamina induz inflamação das vias aéreas e produção de muco em pulmão de camundongos
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Data
2017-08-07
Autores
Vieira, Letícia Vilma dos Santos [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Na inflamação alérgica, a histamina desencadeia papel crucial na indução de sintomas, tais como vasodilatação, broncoconstrição e produção de muco. O objetivo deste estudo foi investigar os efeitos da histamina na inflamação e no remodelamento das vias aéreas, avaliando para tanto a produção de muco e colágeno em modelo murino de inflamação pulmonar. Camundongos Balb/c machos de 20-25g foram estimulados, por via intratraqueal, com histamina em diferentes concentrações (10, 50 e 100 µM) e avaliados após 6, 24 e 48 horas. A partir dos dados resultantes do ensaio dose-resposta, foi realizado tratamento farmacológico, onde animais foram separados em 5 grupos (6 camundongos por grupo): Grupo 1 (PBS), controle não estimulado; Grupo 2 (Histamina), controle estimulado; Grupo 3 (Histamina + Loratadina); Grupo 4 (Histamina + Dexametasona) e Grupo 5 (Histamina + Dexametasona e Loratadina). Analisamos a migração de leucócitos no lavado broncoalveolar (LBA) e no tecido pulmonar. As alterações estruturais no tecido pulmonar e na traqueia foram avaliadas por análise histopatológica, bem como a produção de muco e deposição de colágeno usando Alcian blue/Periodic Acid Shiff e Tricômio de Masson, respectivamente. O sobrenadante do LBA e o tecido pulmonar foram coletados para quantificar os níveis SCF e CCL3 por ELISA de captura. A expressão gênica de Muc5ac, Gob-5, Col1a2 e receptores de histamina foi avaliada por RT-PCR em tempo real. Nossos resultados demonstram que a histamina induz inflamação das vias aéreas, com presença de infiltrado leucocitário no LBA e no tecido pulmonar. Além disso, os animais estimulados com histamina demonstraram aumento significativo na expressão gênica de Muc5ac, Gob-5 e Col1a2 no tecido pulmonar, produção SCF e CCL3 no LBA e pulmão, bem como apresentaram alterações estruturais na traqueia e no tecido pulmonar, tais como infiltrado leucocitário, presença de células caliciformes, produção de muco e depósito de colágeno. O pré-tratamento com dexametasona (DEX) inibiu a migração leucocitária no LBA e tecido pulmonar, e também diminuiu a expressão gênica de Muc5ac no tecido pulmonar, diminuiu a produção de SCF e CCL3 no LBA e pulmão, bem como reduziu a produção de muco e a deposição de colágeno no pulmão. Já o pré-tratamento com loratadina (LOR), bloqueador de H1, inibiu parcialmente a migração celular no LBA, mas não no tecido pulmonar, enquanto que a associação farmacológica entre DEX e LOR diminuiu significativamente a migração leucocitária tanto no LBA como no tecido pulmonar. Com base nos dados acima, sugere-se que a histamina induz inflamação das vias aéreas, promovendo a migração de leucócitos possivelmente através da produção de SCF e CCL3, bem como provoca alterações estruturais na traqueia e no tecido pulmonar, tais como produção de muco, deposição de colágeno, e esses efeitos tem a participação dos receptores H1 e H4.
In allergic inflammation, histamine exerts a crucial role in the induction of symptoms, such as vasodilation, bronchoconstriction and mucus production. The aim of this study was to investigate the effects of histamine in inflammation and airway remodeling, evaluating the mucus production and collagen in a murine model of pulmonary inflammation. Male Balb/c mice of 20-25g were challenged by intratracheal instillation of histamine at different concentrations (10, 50 and 100 μM) and evaluated after 6, 24 and 48 hours. From the data resulting from the dose-response assay, pharmacological treatment was performed, and animals were separated into 5 groups (6 mice per group): Group 1 (PBS), non-challenged control; Group 2 (Histamine), challenged control; Group 3 (Histamine + Loratadine); Group 4 (Histamine + Dexamethasone) and Group 5 (Histamine + Dexamethasone and Loratadine). We analyzed the recruitment of leukocytes in bronchoalveolar lavage (BAL) and lung tissue. Structural changes in lung tissue and trachea were assessed by histopathological analysis, as well as mucus production and collagen deposition using Alcian blue/Periodic Acid Shiff and Masson's Trichrome, respectively. BAL supernatant and lung tissue were collected for SCF and CCL3 levels quantification by capture ELISA. The gene expression of Muc5ac, Gob-5, Col1a2, and histamine receptors was evaluated by RT-PCR real time. Our results demonstrated that histamine induces airway inflammation, with presence of leukocyte infiltrate in BAL and lung tissue. In addition, histamine-challenged animals demonstrated a significant increase in the gene expression of Muc5ac, Gob-5 and Col1a2 in lung tissue, SCF and CCL3 production in BAL and lung, as well as structural changes in the trachea and lung tissue, such as leukocyte infiltrate, presence of goblet cell, mucus production and collagen deposition around the airways. Dexamethasone pre-treatment (DEX) inhibited leukocyte recruitment in BAL and lung tissue, decreased gene expression of Muc5ac in lung tissue, decreases SCF and CCL3 production in BAL and lung, as well as mucus production and collagen deposition in the lung. Already pre-treatment with loratadine (LOR), an H1 blocker, partially inhibited cell migration in BAL, but not in lung tissue, whereas the pharmacological association between DEX and LOR significantly reduced leukocyte recruitment in both the BAL and the lung tissue. Putting the above data together, we suggest that histamine induces airway inflammation, promoting the recruitment of leukocytes possibly through the production of SCF and CCL3, as well as causes structural changes in the trachea and lung tissue, such as mucus production, collagen deposition, and these effects might be mediated by H1 and H4 receptors.
In allergic inflammation, histamine exerts a crucial role in the induction of symptoms, such as vasodilation, bronchoconstriction and mucus production. The aim of this study was to investigate the effects of histamine in inflammation and airway remodeling, evaluating the mucus production and collagen in a murine model of pulmonary inflammation. Male Balb/c mice of 20-25g were challenged by intratracheal instillation of histamine at different concentrations (10, 50 and 100 μM) and evaluated after 6, 24 and 48 hours. From the data resulting from the dose-response assay, pharmacological treatment was performed, and animals were separated into 5 groups (6 mice per group): Group 1 (PBS), non-challenged control; Group 2 (Histamine), challenged control; Group 3 (Histamine + Loratadine); Group 4 (Histamine + Dexamethasone) and Group 5 (Histamine + Dexamethasone and Loratadine). We analyzed the recruitment of leukocytes in bronchoalveolar lavage (BAL) and lung tissue. Structural changes in lung tissue and trachea were assessed by histopathological analysis, as well as mucus production and collagen deposition using Alcian blue/Periodic Acid Shiff and Masson's Trichrome, respectively. BAL supernatant and lung tissue were collected for SCF and CCL3 levels quantification by capture ELISA. The gene expression of Muc5ac, Gob-5, Col1a2, and histamine receptors was evaluated by RT-PCR real time. Our results demonstrated that histamine induces airway inflammation, with presence of leukocyte infiltrate in BAL and lung tissue. In addition, histamine-challenged animals demonstrated a significant increase in the gene expression of Muc5ac, Gob-5 and Col1a2 in lung tissue, SCF and CCL3 production in BAL and lung, as well as structural changes in the trachea and lung tissue, such as leukocyte infiltrate, presence of goblet cell, mucus production and collagen deposition around the airways. Dexamethasone pre-treatment (DEX) inhibited leukocyte recruitment in BAL and lung tissue, decreased gene expression of Muc5ac in lung tissue, decreases SCF and CCL3 production in BAL and lung, as well as mucus production and collagen deposition in the lung. Already pre-treatment with loratadine (LOR), an H1 blocker, partially inhibited cell migration in BAL, but not in lung tissue, whereas the pharmacological association between DEX and LOR significantly reduced leukocyte recruitment in both the BAL and the lung tissue. Putting the above data together, we suggest that histamine induces airway inflammation, promoting the recruitment of leukocytes possibly through the production of SCF and CCL3, as well as causes structural changes in the trachea and lung tissue, such as mucus production, collagen deposition, and these effects might be mediated by H1 and H4 receptors.
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Palavras-chave
histamina, inflamação pulmonar, células caliciformes, produção de muco, deposição de colágeno, remodelamento das vias aéreas, SCF, CCL3, histamine, pulmonary inflammation, goblet cells, mucus production, collagen deposition, airway remodeling