Ultrastructural changes in the alveolar cells of rats injected with Cerastes cerastes cerastes venom

Ultrastructural changes in the alveolar tissue of rats intraperitoneally injected with the Cerastes cerastes cerastes venom were studied in 2 different experimental groups. In the first group, each rat was given 0.73 mg/Kg as a single dose and sacrificed after 24 hours. In the second group, each rat was given a daily dose of 0.42 mg/Kg for 7 days and sacrificed 24 hours after the last injection. Proliferative changes were seen in type II alveolar cells, fibroblasts, lymphocytes, and macrophages. Type II alveolar cells of the lungs developed a large number of surfactant granules. In the 24‐hour‐envenomated rats, type I alveolar cells displayed swollen nuclei and masses of dilated endoplasmic reticulum. In the 7‐day‐treated rats, several plasma cells, adjacent interstitial cells as well as alveolar brush cells, with their characteristic short microvilli, were detected. Large masses of collagen and elastic fibers were also located in the vicinity of the alveolar brush cells and type II alveolar cells. These histopathological changes may be attributed to the body‐immune response and possibly to the development of hyperplasia due to venom‐induced trauma. Nat. Toxins 5:208–221, 1997. © 1998 Wiley‐Liss, Inc.