Effects of Acute Intraperitoneal Injection on Plural Rat Lungs

Purpose: Sulfur mustard (SM), a highly toxic chemical warfare, primarily targets the skin, eye and respiratory tract. Respiratory tract lesions are the most disabling consequences. Mast cells, containing special granules that store histamine and heparin, release leukotrienes. It is known that the surface of mast cells contains specific receptors for 19B. Therefore, mast cells promote allergic reactions when exposed to such chemical compounds as SM. The aim of this study was to evaluate the number of mast cells in the lamina propria of the pleura's visceral layer in the rat lung. Material and Methods: In this study, 30 NMRI male rats weighting 200æ30 grams were randomly divided into 5groups. One group received PBS+DMSO as a solvent by intraperitoneal (IP) injection (sham group), while the other group, i.e., the control group, did not receive any injection. The other three experiment groups received different doses of sulfur mustard (2.5, 10 and 20 mg/kg) by IP injection. Forty-eight hours after injection, the animals were killed, and samples were taken from the lung tissue before being fixed in buffer formalin 10% for 24 hours.The samples were then dehydrated and embedded in paraffin. The paraffin blocks were serially sectioned at 5 micrometer thicknesses and were then stained by hematoxylin-eosin (H&E) toluidine blue and vangison methods. Results: Histological examination and cell counting data revealed that there was insignificant difference in the number of mast cells between the sham and control groups. The results also showed the number of mast cells in the 2.5mg/kg SM group was significantly smaller in comparison with that in the sham and control groups (P<0.016).In addition, the number of mast cells in the 10 and 20 mg/kg SM groups was more significant when compared to that in the sham and control groups (P<0.01). Conclusion: Sulfur mustard seems to have toxic effects in promoting the aggregation of mast cells in the lung tissue.