Mechanical removal of airway epithelium disrupts mast cells and releases granules

Abstract

Many previous investigators have utilized mechanical rubbing as a method for examining effects of epithelial removal. In the present study, we examined whether this procedure also affects mast cell integrity in the underlying lamina propria. We isolated bronchial rings from six ferrets, and we found that removal of epithelium by rubbing decreased the total number of intact mast cells from 10.0 +/- 1.9 to 2.2 +/- 0.6 (SE) mast cells/mm luminal perimeter (P less than 0.01). In addition, we found a very large number of metachromatic particles that appeared to be mast cell granules unassociated with identifiable mast cells. Their identity was confirmed the presence of free mast cell granules and showed that they contained intact membranes. These effects were not observed when the epithelium was removed by enzymatic digestion, but they were observed after mechanical deformation of the bronchi alone. We suggest that mast cell components released by removing or damaging the epithelium may affect the function of various cells in the airway.

Inflammation of bronchial smooth muscle in allergic asthma

“…Several studies have previously reported such an inflammatory response within the airway mucosa and fewer reports have provided ultrastructural data. [1][2][3][4][5][6][7] Until recently, however, the study of inflammation was limited to the submucosa whereas the airway smooth muscle (ASM) was strictly considered as an effector that contracts and/or proliferates in response to inflammatory cell products.…”

Airway epithelial cells modulate cholinergic neurotransmission in dog trachea

“…Murlas reported that the removal of the epithelium augmented the contractions evoked by EFS and histamine, but not those produced by potassium and ACh [25]. However, mechanical removal of the epithelium may alter the contractility of smooth muscle by mechanisms that are independent of the epithelial cell, such as the activation of mast cells [14]. The present findings indicate that products of the epithelial cells are responsible for inhibiting cholinergic neurotransmission.…”

β‐Adrenoceptors mediate inhibition of [3H]‐acetylcholine release from the isolated rat and guinea‐pig trachea: role of the airway mucosa and prostaglandins

“…In control experiments lower S2/S1 ratios were obtained in mucosa-denuded than in mucosa-intact tracheae (see Table 1 and 3), indicating some fading of evoked [3H]-acetylcholine release in the former. It had been shown that mechanical removal of the mucosa, as applied in the present study, disrupts mast cells and causes release of their content (Franconi et al, 1990)…”