Article ID Journal Published Year Pages File Type
2847477 Respiratory Physiology & Neurobiology 2011 11 Pages PDF
Abstract

To test the hypotheses that fetal nicotine exposure alters airway wall composition and enhances the airway response to inhaled methacholine (MCh), lambs were exposed during the last fetal trimester to (1) a low dose (LN) (n = 13, 0.5 mg/kg/d (maternal weight) of free base nicotine, (2) a moderate dose (MN) (n = 10, 1.5 mg/kg/d) or (3) saline (n = 14). Studies were performed at postnatal days 12, 26 and 52. Prenatal nicotine exposure induced a dose- and age-related hyper-responsiveness to MCh in the proximal airways. Moment analysis of nitrogen decay curves showed no nicotine or MCh effects on ventilation homogeneity or gas-mixing efficiency in the distal airways during MCh inhalations suggesting a bimodal response. Fetal nicotine exposure increased epithelial mucosubstance volume in central (LN, MN) and distal bronchi (LN), increased smooth muscle volume in distal bronchi and bronchioles (LN) and decreased bronchiolar diameter (MN). In conclusion, third trimester nicotine exposure causes hyperreactive proximal airways and alters proximal airway wall composition associated with airflow limitation.

Related Topics
Life Sciences Biochemistry, Genetics and Molecular Biology Physiology
Authors
, , , , ,