Electron microscopic study on clara cells in the lung of adult mice in response to naphthalene injection

ABSTRACT

The present work aimed at studying the effect of intraperitoneal administration of naphthalene, an organic chemical, on nonciliated [Clara] cells in terminal bronchioles and lobar bronchi. Adult mice were divided into four groups, each given a single intraperitoneal injection of the following doses respectively [50, 100, 200 and 300 mg / kg] of naphthalene in corn oil. The animals were sacrificed 48 hours later. Retrograde recovery changes were studied fourteen days following naphthalene administration. Epithelial changes included cellular swelling, vacuolation and exfoliation of Clara cells. Minimal bronchiolar epithelial changes were observed in the first group [50 mg / kg]. In the second group [100 mg / kg], the number of Clara cells that showed vacuolation increased. In the third and fourth groups [200 and 300 mg / kg], almost all of the nonciliated eels lining terminal bronchioles were vacuolated and exfoliated. No detectable changes were noted in lobar bronchi except in the fourth group [300 mg / kg] where lobar bronchi showed vacuolation and exfoliation of Clara cells. Nonciliated cells in both terminal bronchioles and lobar bronchi resembled controls in recovery mice