Insulin Modulates Cytokine Release, Collagen and Mucus Secretion in Lung Remodeling of Allergic Diabetic Mice

Abstract

IntroductionThe role of insulin in lung remodeling in a model of asthma in healthy and diabetic mice was evaluated.Material and methodsDiabetic male BALB/c mice (alloxan, 50 mg/kg, intravenous) and controls were sensitized by subcutaneous (s.c.) injection of ovalbumin (OA, 20 µg) in aluminum hydroxide (Al(OH)3, 2 mg) 10 days after the alloxan injection and received the same dose 12 days later. Six days after the last sensitization, animals were nebulized with OA solution for 7 days. The first set of diabetic and control mice received 2 and 1 IU, respectively, of s.c. neutral protamine Hagedorn (NPH) insulin and were analyzed 8 h later. The second set of diabetic and control mice received 2 and 1 IU, respectively, of insulin 12 h before the OA challenge and half doses of insulin 2 h before each the seven OA challenges. Twenty-four hours after the last challenge, the following analyses were performed: (a) quantification of the cells in the bronchoalveolar lavage fluid (BALF), the white cell count, and blood glucose; (b) morphological analysis of lung tissues by hematoxylin and eosin staining; (c) quantification of collagen deposition in lung tissues and mucus by morphometric analysis of histological sections stained with Masson’s trichrome and periodic acid-Schiff (PAS), respectively; and (d) quantification of the cytokine concentrations (IL-4, IL-5, and IL-13) in the BALF supernatant.ResultsCompared to controls, diabetic mice had significantly reduced inflammatory cells (81%) in the BALF, no eosinophils in the BALF and peripheral blood and reduced collagen deposition and mucus in the lungs. BALF concentrations of IL-4 (48%) and IL-5 (31%) decreased and IL-13 was absent. A single dose of insulin restored peripheral blood eosinophils and BALF mononuclear cells but not BALF eosinophils, collagen deposition, and mucus levels. However, multiple doses of insulin restored both total cells and eosinophils in the BALF and peripheral blood, BALF cytokines, and collagen deposition and mucus secretion into the lungs.ConclusionThe results suggest that insulin modulates the production/release of cytokines, cell migration, deposition of collagen, and mucus secretion in lung remodeling of a mouse model of asthma.

Insulin Modulates the Immune Cell Phenotype in Pulmonary Allergic Inflammation and Increases Pulmonary Resistance in Diabetic Mice

“…In this asthma model we suggest that in diabetic mice, previously challenged with OVA, reduced cytokines production and defective expression of adhesion molecules, may partially explain defective neutrophils migration and ineffective inflammation (33). More recently we have also shown that insulin treatment might be involved with airway remodeling since we obtained better collagen airway deposition and mucus secretion when diabetic mice were insulin treated (29). Our group also studied that lack of insulin may cause permanent defect in bone marrow compartment (34), since bone marrow derived macrophages from diabetic rats differ phenotypically from control, healthy animals.…”

“…Acute treatments with insulin (3 days) were ineffective (28). According to the results of a recent study of a model of latephase pulmonary allergic inflammation, insulin restores mucus secretion and collagen deposition and increases cell migration, mainly eosinophils, in the airways of diabetic and asthmatic animals (29).…”

Insulina modula o fenótipo de células imunes na inflamação alérgica pulmonar, aumentando a resistência pulmonar de camundongos diabéticos

“…A glicemia foi determinada através de um monitor de glicose (Accu-Check Active -Roche Diagnosis®), utilizando-se amostras de sangue obtidas da extremidade da cauda dos animais. Somente foram utilizados, como diabéticos, animais com glicemia superior a 300 mg/dL(SPILLER et al, 2012;FERREIRA et al, 2017). Brasil) que fornece partículas de 0,5-10µm de diâmetro, em aproximadamente 0,75 cc/min.…”

“…Brasil) que fornece partículas de 0,5-10µm de diâmetro, em aproximadamente 0,75 cc/min. Os experimentos foram realizados 24 horas após o último desafio antigênico(STUMM, et al, 2011;FERREIRA et al, 2017). 3.4 Tratamento com insulina O grupo de diabéticos que receberam o desafio com OVA, foram tratados com 2UI de insulina NPH via subcutânea, 12h antes de cada desafio (às 19:00 horas) e 1UI de insulina NPH via subcutânea 2 horas antes de cada desafio (às 07:00 horas).…”

“…BELLA et al, 2017). Porém para camundongos da linhagem BALB/c essa dose, foi padronizada utilizando 50mg/kg de aloxana, devido a grandes perdas de animais, utilizando a dose de 60mg/kg(FERREIRA et al, 2017). como também o remodelamento das vias aéreas.…”