GUINEA-PIG ASTHMA INDUCED BY RED SOFT CORAL (DENDRONEPHTHYA-NIPPONICA) INHALATION

Spiny lobster fishermen on the Pacific coast of Miyazaki Prefecture in Japan develop bronchial asthma due to occupational sensitization to r ed soft coral (Dendronephthya nipponica). To assess the role of sensit ization in the development of bronchial hyperresponsiveness and the re lationship between bronchial responsiveness and bronchial inflammation , we established a guinea pig model of red soft coral induced asthma. Twenty-four guinea pigs were intramuscularly immunized with a priming dose of red soft coral, 5 OD280 (15 mg protein) per 0.5 ml, and 0.5 ml complete Freund's adjuvant on day 1. Booster doses were repeated on d ay 15. By day 43 all sensitized animals showed high hemagglutination t iters against red soft coral conjugated sheep erythrocytes and high Ig G1 titers by passive cutaneous anaphylaxis. On day 43, the animals wer e challenged by inhalation of red soft coral extracts, 20 OD280 for 30 min. The respiratory resistance was monitored by the oscillation meth od. The respiratory resistance increased immediately upon inhalation i n all sensitized animals and returned to baseline within 4 h. The bron chial reactivity to acetylcholine, measured 6 h after red soft coral i nhalation in the sensitized animals when the respiratory resistance wa s returned to baseline, increased significantly (p<0.05) as compared w ith the values measured 24 h before inhalation. The acetylcholine resp onse measured 30 h later did not differ from preinhalation levels. The re was a significant difference in the number of eosinophils (p<0.001) in lamina propria and epithelium and of lymphocytes (p<0.05) in the l amina propria 6 h after inhalation in the sensitized animals. There wa s also a significant difference (p<0.05) in the number of eosinophils in the epithelium 30 h after inhalation. The increased airway responsi veness to acetylcholine in the sensitized animals correlated with an i ncrease in the number of eosinophils in lamina propria and epithelium.