ABSTRACT
Mechanism responsible for the enlargement of end-expiratory lung volume (EELV) induced by chronic hypoxia remains unclear. The fact that the increase in EELV persists after return to normoxia suggests involvement of morphological changes. Because hypoxia has been also shown to activate lung mast cells, we speculated that they could play in the mechanism increasing EELV similar role as in vessel remodeling in hypoxic pulmonary hypertension (HPH). We, therefore, tested an effect of mast cells degranulation blocker disodium cromoglycate (DSCG) on hypoxia induced EELV enlargement. Ventilatory parameters, EELV and right to left heart weight ratio (RV/LV+S) were measured in male Wistar rats. The experimental group (H+DSCG) was exposed to 3 weeks of normobaric hypoxia and treated with DSCG during the first four days of hypoxia, control group was exposed to hypoxia only (H), two others were kept in normoxia as non-treated (N) and treated (N+DSCG) groups. DSCG treatment significantly attenuated the EELV enlargement (H+DSCG = 6.1+/-0.8; H = 9.2+/-0.9; ml +/-SE) together with the increase in minute ventilation (H + DSCG = 190+/-8; H = 273 +/- 10; ml/min +/- SE) and RV/LV + S (H + DSCG = 0.39 +/- 0.03; H = 0.50 +/- 0.06).
Subject(s)
Cromolyn Sodium/pharmacology , Exhalation/drug effects , Hypoxia/drug therapy , Hypoxia/physiopathology , Lung/physiopathology , Respiratory Mechanics/drug effects , Tidal Volume/drug effects , Animals , Anti-Asthmatic Agents/pharmacology , Hypoxia/complications , Lung/drug effects , Lung Volume Measurements , Male , Rats , Rats, WistarABSTRACT
Prolonged cultivation of separated rat lung mast cells (LMC) in vitro is necessary to better investigate a possible role of LMC in different stages of tissue remodeling induced by hypoxia. Rat lung mast cells (LMC) were separated using a protocol including an improved proteolytic extraction and two subsequent density gradient separations on Ficoll-Paque PLUS and a new generation of Percoll, i.e. Percoll PLUS. Instead of usual isotonic stock Percoll solution, an alternative "asymptotically isotonic" stock solution was more successful in our density separation of LMC on Percoll PLUS. Separated cells were cultivated for six days in media including stem cell factor, interleukins IL-3 and IL-6, and one of two alternative mixtures of antibiotics. These cultivations were performed without any contamination and with only rare changes in cell size and morphology. Model co-cultivation of two allogenic fractions of LMC often caused considerable rapid changes in cell morphology and size. In contrast to these observations no or rare morphological changes were found after cultivation under hypoxic conditions. In conclusions, we modified separation on Percoll PLUS to be widely used, altered LMC separation with respect to purposes of long-lasting cultivation and observed some model morphological changes of LMC.
Subject(s)
Cell Separation/methods , Isotonic Solutions/chemistry , Lung/cytology , Mast Cells/cytology , Povidone/chemistry , Silicon Dioxide/chemistry , Animals , Centrifugation, Density Gradient , Lung/metabolism , Male , RatsABSTRACT
Hydrogen peroxide production was measured in non-elicited rat peritoneal macrophages using luminol-dependent chemiluminescence (LDCL). Isolated cells were activated by a chemotactic peptide (FMLP) or by a phorbol ester (PMA) or by the combination of both. A hundred-fold higher LDCL intensity was achieved with PMA relative to FMLP. However, when FMLP was added subsequently to PMA it produced approximately the same response as did PMA. These measurements were carried out with cells isolated from controls and from animals exposed to normobaric hypoxia (10% O2) for 3 hours, 3 days, or 21 days. Hypoxia had a dual effect. Acutely (within 3 hours) it attenuated the production of hydrogen peroxide triggered by PMA, whilst during longer exposure (3 or 21 days) it increased the response induced by FMLP. Hypoxia can thus modulate the capacity of respiratory burst in peritoneal macrophages.
