Radiation exposure and the effect of piroxicam and diclofenac on mediator release from isolated guinea-pig lung.
The effects of radiation exposure and drug treatment on the immediate type of hypersensitivity reaction were studied. Guinea-pigs were sensitized by s.c. injections of antigen. The animals were killed 3 weeks later and the lungs were perfused through the pulmonary artery. The perfusate was allowed to superfuse a guinea-pig ileum to estimate its total content of mediators. Results revealed that the mere injection of antigen to the perfused lung resulted in the release of spasmogens which caused contraction of the guinea-pig ileum. Analysis of the effluent showed an increase in the amount of PGs (measured biologically) and histamine (measured fluorimetrically) released during challenge. The response of the ileum to the antigen challenge was inhibited by the infusion of diclofenac (20 micrograms.ml-1) or piroxicam (25 micrograms.ml-1). The drugs also inhibited the release of PGs and histamine from the perfused lungs. Exposure of animals to gamma-radiation, before sensitization, caused a reduction in the amount of mediators released during challenge. On the other hand, in nonsensitized animals, a single radiation dose level of 2 Gy caused fluctuation in the amount of PGs and histamine released during challenge throughout the 3 weeks period of the experiment. Diclofenac and piroxicam effectively reduced the amount of mediators released from sensitized perfused lung isolated from both nonirradiated and irradiated animals. This may, at least partly, explain their protective effect against the exaggerated inflammatory response following gamma-irradiation exposure.
Khayyal
M T
MT
Department of Pharmacology, Faculty of Pharmacy, Cairo University, Egypt.
Roushdy
H
H
Saleh
S
S
el-Ghazaly
M
M
Kenawy
S
S
el Mazar
M A
MA
D000707:Anaphylaxis / Q000139:chemically induced; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology; D004008:Diclofenac / Q000494:pharmacology*; D005260:Female; D005720:Gamma Rays; D006168:Guinea Pigs; D006636:Histamine Release / Q000187:drug effects; D007082:Ileum / Q000187:drug effects; D066298:In Vitro Techniques; D008168:Lung / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects*; D008297:Male; D010477:Perfusion; D010894:Piroxicam / Q000494:pharmacology*; D011453:Prostaglandins / Q000378:metabolism
D000894:Anti-Inflammatory Agents, Non-Steroidal; D011453:Prostaglandins; D010894:Piroxicam; D004008:Diclofenac