Jeffery P K, Brain A P, Shields P A, Quinn B P, Betts T
Department of Lung Pathology, Brompton Hospital, London, England.
Scanning Microsc. 1988 Mar;2(1):545-52.
The effects on surface morphology of airway epithelium of cigarette smoke (CS) inhalation alone (experiments one and two) or of CS in combination with hypovitaminosis A (experiment two) was investigated using specific pathogen free rats. Eight morphologically distinct cell types were distinguished overall. Apart from atypical squamous lesions, each of the other cell types could be found in varying proportions in all experimental groups. CS alone caused an increase in the frequency with which intra-lumenal mucus was seen and an increase in the occurrence of secretory cells of types IV (i.e., 'merocrine') and V (i.e., 'apocrine'). In experiment one, the area of trachea covered by cilia as determined by point counting increased significantly (P less than 0.01). Hypovitaminosis A was induced by lowering the dietary intake of vitamin A to a minimum, defined level. Rats showed an approximately 75% decrease in plasma retinol levels and a 95-100% decrease in hepatic stores of vitamin A. At this level, hypovitaminosis A alone had no significant effect on airway epithelial morphology. Foci of squamous metaplasia (squamous cells of type VIIIa) were found in all groups but extensive squamous metaplasia of the larynx and squamous lesions of atypical appearance (type VIIIb) were found only in the vitamin deficient group exposed to CS. The results suggest the synergistic effects of reduced vitamin A and CS may be important in the induction of atypical squamous changes which may predispose the airway to the development of squamous carcinoma.
使用无特定病原体大鼠研究了单独吸入香烟烟雾（CS）（实验一和实验二）或CS与维生素A缺乏症联合作用（实验二）对气道上皮表面形态的影响。总体上区分出了八种形态上不同的细胞类型。除了非典型鳞状病变外，其他每种细胞类型在所有实验组中都有不同比例的存在。单独的CS导致管腔内黏液出现频率增加，以及IV型（即“局浆分泌型”）和V型（即“顶浆分泌型”）分泌细胞的出现频率增加。在实验一中，通过点计数确定的被纤毛覆盖的气管面积显著增加（P小于0.01）。通过将维生素A的饮食摄入量降低到最低的、确定的水平来诱导维生素A缺乏症。大鼠血浆视黄醇水平下降约75%，肝脏维生素A储备下降95 - 100%。在此水平下，单独的维生素A缺乏症对气道上皮形态没有显著影响。在所有组中均发现了鳞状化生灶（VIIIa型鳞状细胞），但仅在暴露于CS的维生素缺乏组中发现了广泛的喉部鳞状化生和非典型外观的鳞状病变（VIIIb型）。结果表明，维生素A减少与CS的协同作用可能在诱导非典型鳞状变化中起重要作用，而非典型鳞状变化可能使气道易患鳞状细胞癌。
