Effect of Passive Smoking on the Lung of Young Lambs

Abstract

ABSTRACT. The effect of passive smoking on lung histology, lung mechanics, and airway responsiveness (AR) was studied in 2-month-old lambs. Two groups of lambs were studied; 17 were exposed to cigarette smoke (CS) and 13 served as age-and sex-matched controls. Starting at 1 month of age, CS lambs had 25 daily exposures to the smoke generated from eight cigarettes. A smoking machine was constructed for the study using a Bird Ventilator. Two days prior to lung function testing, lambs were anesthetized and a Silastic balloon was placed in the pleural space for later measurement of pleural pressure. At the beginning of each study, lambs were intubated with a nasotracheal tube over a flexible fiberoptic bronchoscope. Lung mechanics (dynamic compliance, resistance of the lung, functional residual capacity) and AR were measured using a whole body plethsymograph. AR to inhaled histamine, carbachol, and citric acid was measured in each lamb on 3 separate days by giving five breaths of increasing concentrations of the aerosol in a noncumulative fashion. AR was measured both within 24 h of the final exposure to CS and at 3-7 days after CS. After the final AR was measured, lambs were anesthetized and an open lung biopsy performed. Control lambs had the same studies as CS lambs performed at an equivalent age. After 25 daily exposures to CS in 17 lambs, mean dynamic compliance was 0.024 2 0.009 liter/ cm H 2 0 , lung resistance was 2.56 + 1.32 cm H 2 0 . liter-'. s, and functional residual capacity was 0.725 + 0.234 liter. These values were not significantly different (p > 0.05) from those of the control lambs. Exposure to CS did not significantly change AR to any of the three bronchoprovocation agents tested. Histologic examination of lung tissue showed mild to moderate interstitial mononuclear cellular infiltrate, cellular debris in some airways, and occasional peribronchial inflammation in CS lambs but not in controls. Thus, passive smoking for 1 month in young lambs was not associated with a detectable alteration in lung mechanics or airway responsiveness at a time when inflammatory cells were found in the lung. (Pediatr Res 20: 853-858, 1986) Abbreviations CS, cigarette smoke COHb, carboxy hemoglobin FRC, functional residual capacity BTPS, body temperature, pressure, saturation yT, tidal volume V, flow Pa, airway opening pressure

Validation of a new automatic smoking machine to study the effects of cigarette smoke in newborn lambs

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Barriers to inhaled gene therapy of obstructive lung diseases: A review

“…CS models have been also generated using other larger species such as guinea pigs [381, 382]. Guinea pig-based CS models have been favored by several groups due to its unique advantages, including relatively close resemblance to human lung physiology and anatomy [383–385] as well as lung alveolarization at birth which may be beneficial for pre- and neonatal studies [386].…”

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“…In young lambs morphological changes in the lung following second hand smoke exposure can appear after a short period of time (<1 month) (Stecenko et al, 1986) making it a useful model for smoke exposure studies. In addition, the lungs of lambs are still developing after birth similar to humans, and therefore the model is potentially useful for research into the effects of second hand smoke on infant lung development.…”