Characteristic modifications of the breathing pattern of mice to evaluate the effects of airborne chemicals on the respiratory tract

Abstract

A system was developed for exposure of unanesthetized mice to airborne chemicals and for continuous measurement of their breathing pattern prior to, during and following exposure. By measuring inspiratory and expiratory airflows (VI and VE), and integration with time to yield tidal volume (VT), we obtained characteristic modifications to the normal breathing pattern. These permitted recognition that a specific portion of the respiratory tract was affected by the selected airborne chemicals. Following recognition, we also quantitated the degree of effect using one specific measurement in each case. An effect on the upper respiratory tract, induced by the sensory irritant, 2-chlorobenzylchloride, was quantitated by measuring a decrease in respiratory frequency. An effect on the conducting airways, induced by the airway constrictor, carbamylcholine, was quantitated by a decrease in VE at the mid-point of VT. An effect at the alveolar level, induced either by the vagal nerve ending stimulant, propranolol, or by the pulmonary irritant, machining fluid G, was quantitated by an increase in the length of a pause induced at the end of expiration. The system is easy to construct and operate and can be used to rapidly evaluate the effects of airborne chemicals on the respiratory tract.

Limonene and its ozone-initiated reaction products attenuate allergic lung inflammation in mice

“…Rapid shallow breathing (RSB) is another reflex change in respiration due to pulmonary irritation. Comprehensive descriptions of the breathing parameters and their analyses have been made elsewhere (Alarie 1973;Vijayaraghavan et al 1993;Nielsen et al 1999). …”

“…By using a factorial design, where allergic and nonallergic animals were exposed to the same air pollutants, it was possible to investigate if: (a) limonene, ozone, or their reaction products caused acute effects on respiration and inflammation in non-allergic mice; (b) limonene, ozone or their reaction products aggravated or attenuated an existing pulmonary allergic inflammation; and (c) the inflammatory and irritant responses to limonene, ozone or their reaction products differed between allergic and nonallergic mice. Standard mouse models of airway irritation based on head-out plethysmography (Alarie 1973;Nielsen et al 1999;Vijayaraghavan et al 1993) and airway allergy to the model allergen ovalbumin (OVA) (Kumar et al 2008) were used to test the hypotheses.…”

Intervention of Thymus and Activation-Regulated Chemokine Attenuates the Development of Allergic Airway Inflammation and Hyperresponsiveness in Mice

“…OVA-treated control mice were injected with the same amount of control Ab (hamster Ig fraction; Dako, Santa Barbara, CA) at the same time points as during the treatments. The dose and time schedules of Ab treatment were basically decided according to previous reports with similar experimental strategy (27).…”

Intratracheal Priming with Ovalbumin- and Ovalbumin 323–339 Peptide-Pulsed Dendritic Cells Induces Airway Hyperresponsiveness, Lung Eosinophilia, Goblet Cell Hyperplasia, and Inflammation

“…This is an index of airway resistance calculated by software from box (plethysmograph) pressure recorded during the inhalation and exhalation of the animals. Penh is defined as [(expiratory time/relaxation time) Ϫ 1][peak expiratory flow/peak inspiratory flow], and it reflects both the characteristics of pronounced changes in box pressure during early expiration and the increased interval between breaths during broncho-constriction (18,19). The ratios of the Penh values at a given methacholine concentration to the basal Penh values of the animals were used in AHR plots to adjust for differences in individual animals.…”