Morphologic Changes in Cultured Normal Human Nasal Epithelial Cells Following Treatment with Histamine

ABSTRACT

The aims of this study are to observe morphologic changes in normal human nasal epithelial (NHNE) cells caused by varying concentrations of histamine, to evaluate the changes in relation to the degree of epithelial differentiation, and to examine whether these changes are caused by the proper action of histamine or are general inflammatory processes represented by lipopolysaccharide (LPS). Cultured NHNE cells were treated with histamine diphosphate and LPS 0111 : B4 at different concentrations : 20 ng/ml, 200 ng/ml, 2 microgram/ml and 20 microgram/ml. The timing of the treatment was conducted in one of two ways : a duration of 48 hours on floating day 12 or a duration of seven days on floating day seven. On floating day 14, all specimens were collected, and hematoxylin & eosin staining and scanning electron microscopy (SEM) were conducted. The areas of ciliated and secretory cell were calculated with the Optimas program. In SEM of specimens that were given 48-hour treatments of histamine and LPS at 20 microgram/ml dosages, coverage by secretory cells had increased and damaged cilia were noted. In SEM of specimens given the seven-day treatment, enlargement of the secretory cell area and damaged cilia were observed after a treatment of 20 microgram/ml LPS, but in specimens treated with histamine, findings were normal. Morphologic changes caused by histamine treatment may be a nonspecific finding observed in inflammation, and the changes can vary according to the differentiation of the epithelium.