Shields P A, Jeffery P K
Department of Lung Pathology, Brompton Hospital, London, UK.
Br J Exp Pathol. 1987 Oct;68(5):705-17.
The effects of 1-14 days cigarette smoke inhalation on the morphology of airway epithelium were compared in normal and vitamin A-deficient rats. Control rats for each diet group received 'sham' exposure of air only. The vitamin A-deficient diet caused highly significant decreases in plasma retinol and liver retinyl palmitate (P less than 0.001). Vitamin A-deficiency alone caused a squamous change without stratification which resulted in a slight but statistically significant decrease (P less than 0.005) in the thickness of tracheal epithelium. In rats fed a diet containing an adequate amount of vitamin A (i.e. 4000 iu/kg), cigarette smoke exposure for 14 consecutive days caused cell hyperplasia and hypertrophy and significant thickening of tracheal epithelium (P less than 0.01) without any squamous change. In vitamin A-deficient rats, cigarette smoke caused an epidermoid metaplasia with epithelial thickening in excess of that seen with cigarette smoke alone: i.e. the thickened epithelium was stratified, keratinized and squamous. The increase in thickness was evident after 7 days and maximal after 14 days of smoke exposure whilst the epidermoid change was most pronounced at 7 days. Whilst no secretory cells were detected in the squamous areas, the number of mucous cells in the intervening mucociliary epithelium was greatly increased. Vitamin A-deficiency may, therefore, augment the metaplastic effects of cigarette smoke by favouring an early, florid epidermoid response.
在正常和维生素A缺乏的大鼠中，比较了吸入1 - 14天香烟烟雾对气道上皮形态的影响。每个饮食组的对照大鼠仅接受空气的“假”暴露。维生素A缺乏饮食导致血浆视黄醇和肝脏棕榈酸视黄酯显著降低（P < 0.001）。单独的维生素A缺乏导致无分层的鳞状变化，导致气管上皮厚度略有但统计学上显著降低（P < 0.005）。在喂食含适量维生素A（即4000 iu/kg）饮食的大鼠中连续14天暴露于香烟烟雾导致细胞增生和肥大以及气管上皮显著增厚（P < 0.01），且无任何鳞状变化。在维生素A缺乏的大鼠中，香烟烟雾导致表皮样化生，上皮增厚超过单独香烟烟雾所致：即增厚的上皮分层、角化且呈鳞状。烟雾暴露7天后厚度增加明显，14天后达到最大，而表皮样变化在7天时最为明显。虽然在鳞状区域未检测到分泌细胞，但中间的黏液纤毛上皮中的黏液细胞数量大大增加。因此，维生素A缺乏可能通过促进早期、明显的表皮样反应增强香烟烟雾的化生作用。
