Alteration of pulmonary neuroendocrine cells during epithelial repair of naphthalene-induced airway injury

Whole-mount airway preparations isolated from the lungs of mice treated by intraperitoneal injection of naphthalene and allowed to recover for 5 days were examined for the distribution and abundance of solitary pulmonary neur oendocrine cells (PNECs) and neuroepithelial bodies (NEBs) along the main a xial pathway of the right middle lobe. Sham mice treated with corn oil vehi cle were examined in a similar manner. An antibody to calcitonin gene-relat ed peptide, a neuroendocrine cell marker, was used to identify the location , size, and number of PNECs and NEBs in the airways. After naphthalene trea tment and epithelial repair, NEBs were significantly increased along the wa lls of the airways as well as on branch point ridges, The surface area cove red by NEBs com posed of 20 or fewer PNECs was significantly enlarged after naphthalene treatment compared with control NEBs of an equivalent cell num ber. The PNEC number per square millimeter was also increased more than thr eefold above control values after naphthalene treatment, These findings pro vide further support for a key role of neuroendocrine cells in the reparati ve process of airway epithelial cell renewal after injury.