Vitamin A depletion induced by cigarette smoke is associated with the development of emphysema in rats.
We showed previously that vitamin A deficiency per se causes emphysema. Benzo(a)pyrene, a constituent in cigarette smoke, induces vitamin A depletion when administered to rats; therefore, we tested the hypothesis that cigarette smoke induces vitamin A depletion, which is associated with the development of emphysema. Male weanling rats were fed a purified AIN-93G diet and divided into two groups. The experimental group was exposed to cigarette smoke from 20 nonfiltered commercial cigarettes/d for 5 d/wk, whereas the control group was exposed to air. After 6 wk, tissues were collected for histological and biochemical analyses. Retinol levels were measured in serum, lung and liver. The trachea, lung and liver were examined for histological changes. Vitamin A levels decreased significantly in serum, lung and liver of smoke-treated rats. Histological examination revealed the presence of interstitial pneumonitis along with severe emphysema. There was a significant inverse relationship between vitamin A concentration in the lung and the severity of emphysema (r = -0.69 and P < 0.03). Detachment or hyperplasia (and metaplasia) of the tracheal epithelium and liver vacuole formation also were evident in the smoke-treated rats. The results of this research indicate that exposure to cigarette smoke induces vitamin A depletion in rats, which is associated with the development of emphysema.
Li
Ting
T
Department of Human Nutrition, Kansas State University, Manhattan, KS 66506, USA.
Molteni
Agostino
A
Latkovich
Predrag
P
Castellani
William
W
Baybutt
Richard C
RC
D000818:Animals; D008099:Liver / Q000378:metabolism / Q000473:pathology; D008168:Lung / Q000378:metabolism / Q000473:pathology; D017563:Lung Diseases, Interstitial / Q000209:etiology; D008297:Male; D009994:Osmolar Concentration; D011656:Pulmonary Emphysema / Q000209:etiology* / Q000473:pathology / Q000503:physiopathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012720:Severity of Illness Index; D012906:Smoke / Q000009:adverse effects*; D014026:Nicotiana; D014132:Trachea / Q000473:pathology; D014801:Vitamin A / Q000037:antagonists & inhibitors* / Q000097:blood / Q000378:metabolism
D012906:Smoke; D014801:Vitamin A