Type II alveolar epithelial cells and free alveolar cells after intratumor TNF-a administration

Abstract

The experiment used Morris hepatoma 5123 series growing in muscles of the Buffalo rats. A suspension of 3 x 1 0 ~n eoplastic cells was injected into the right hind leg of the animals. After fourteen days, TNF-a was administered into the tumour in a dose of 1 .5x104 U124 hours in 0.5 m1 PBS solution. The group 1 animals were injected for 4 days and group 11 for 8 days. Control groups consisted of rats with injected Morris hepatoma which were given PBS solution instead of TNF-a (group 111 A and B) and animals without the hepatoma, given 4 or 8 TNF-a, respectively (groups IV A and B). In the present study, we have explored the effect of intratumor TNF-a administration on the composition of cells isolated from the lungs through multiple bronchoalveolar lavages (BAL). Ultrastructural evaluation of the pulmonary tissue was done using a transmission electron microscope (TEM), with special attention paid to type 11 alveolar epithelial cells and free alveolar cells. Examinations in TEM in groups 1, 11 and IV (A and B) found, in the lumen of alveoli, an increase in the number of alveolar macrophages (AM) with morphological features of intensified activity and AM with numerous secondary lysosomes containing material of phospholipid structure. Also, numerous type 11 alveolar epithelial cells with emptied lamellar bodies were observed. The above mentioned changes were especially marked after eightfold TNF-a administration. In groups 1, 11 and IV (A and B), compared with group 111, a significant increase was found in the total number of cells isolated by BAL as well as in the number of cells with positive reaction in staining according to Beckstead's method. It may indicate that the changes in the parameters mentioned above are related to TNF-a action. The results obtained indicate the possibility of systemic effect of TNF-a after its administration into the experimental Morris hepatoma.