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! I I I I I I I I I I I I I I I I I #83 AUTHOR: PARK, SUNG SUH, YUTAKA KIKKAWA, IRENE P. GOLDRING, MARIE M. DALY, MELVIN SELEFSKY, CHANG SHIM, MORRIS SPIERER, AND YOYOHIKO MORITA DATE= 1977 TITLE: AN ANIMAL MODEL OF CIGARETTE SMOKING IN BEAGLE DOGS - CORRELATIVE EVALUATION OF EFFECTS ON PULMONARY FUNCTION, DEFENSE, AND MORPHOLOGY CITATION= AMERICAN REVIEW OF RESPIRATORY DISEASE 113: 971-979(1977) STUDY DESIGN= One year old male beagle dogs were divided into 2 experimental groups and 1 control group. Dogs in the experimental group were trained to accept a face mask and mouthpiece and to breathe through the mouthpipe. All dogs after a conditioning period were trained to smoke 100 puffs per day' in 2 smoking sessions, consuming 8 1R 1 University of Kentucky reference cigarettes (Group 1) Smoking was suspended on weekends and holidays. After six months of exposure, one half were killed and the other half allowed to live an additional 4 months for recovery studies. A second set of dogs were obtained, and again after conditioning, were exposed as before, however the number of sessions were increased to 4 per day (double exposure of the first group). Non-invasive methods for bioassay during life were carried out. These included; arterial blood gases, diffusing capacity of the lung for CO, functional residual capacity (FRC) and lung clearance index, respiratory resistance and tracheal mucous flow velocity. In group 1, all of the measurements except FRC and lung clearance indices, were made 4 and 6 months after start of exposure to smoking and also 2 and 4 months after start of recovery period. In group 2, all measurements were made at 3 month intervals. The trachea, lungs and heart were excised for postmortem evaluations. The left lung was sectioned for morphologic studies, while the right upper lobs an d trachea was used for studies of lung mechanics. RNDINGS/RESULTS/CONCLUSIONS: In group 1, the premortem studies of arterial blood gases and nonelastic respiratory system resistance obtained after 4 and 6 months of smoking and the postmortem studies of lung mechanics obtained after completion of exposure and after a 4-month recovery period showed no significant differences between the experimental and control groups. In group 2, premortem pulmonary function data obtained at 2- to 3- month intervals again showed no significant difference between control and experimental animals, with the exception that the values of FRC and non elastic respiratory system resistance obtained after 11 months of smoking were slightly lower and slightly higher, respectively. Postmortem results also showed stmitar trends for these two functions. In both groups 1 and 2, a significant decrease in tracheal mucous flow velocity was observed toward the end of the smoking experiment. Postmortem in vitro measurements of ciliary beat, showed no significant difference between the experimental and control dogs in both groups. In group 1, this decrease in flow was observed at the end of the 6 month period, whereas in group 2, the decrease of similar degree was noted only toward the end of the 1 year period of smoking. The data obtained from alveolar macrophage function studies in groups 1 and 2 are summarized as follows: greater number of cells harvested in group 2, an increased initial latex uptake in group 2 and a decrease in bacteriosuppressive activity in group 1. In both groups 1 and 2, no significant difference was noted between the experimental and control dogs in various morphometric indices, including bronchiolar luminal size distribution and volume proportions of alveolar space and septa, respiratory duct spaces, small bronchus lumen, and vessels and connective tissue.