Lung - Vacuolization, Cytoplasmic

Cytoplasmic vacuolization in the lungs is most commonly seen in the airway epithelium of mice (Figure 1, Figure 2, Figure 3, and Figure 4) but may also be seen in other species and in other types of epithelial cells. Cytoplasmic vacuolization is generally thought to represent a reversible degenerative change. The vacuolization may represent distended and pinched off endoplasmic reticulum. Mitochondrial damage may lead to insufficient beta-oxidation and accumulation of triglycerides within the mitochondria or cytoplasm. Damage to cellular components involved in protein synthesis may lead to decreased levels of apolipoproteins, which lead to decreased lipid transport and the accumulation of lipid in the cytoplasm. The vacuoles may be large and distend the cytoplasm, but frequently the vacuoles are very small (i.e., visible only with electron microscopy) and numerous and give the cytoplasm a pale or bluish gray appearance. Since cytoplasmic vacuolization is thought to be a degenerative change, it is often accompanied by other changes associated with tissue damage, such as inflammation and necrosis.