Objective:  

To determine whether zymosan priming protects rats against oxygen toxicity.

Methods:  

37 rats were used with 6 treatment groups. 11 received zymosan priming (3 daily i. v. injections with 15 mg zymosan and 2 days rest) before 52 h exposure to either normobaric hyperoxia (ZP group, 5 rats) or air (ZPA group, 6 rats)]. Two other groups received saline (Saline group, 9 rats) or zymosan by i. p. injection (Zip group, 6 rats) before hyperoxia. A fifth group received a non-priming (NP) treatment with zymosan before hyperoxia (ZNP group, 6 rats, single i. v. injection) and a final group received no treatment (Air group, 5 rats). Pleural effusions and lung injury were then assessed.

Results:  

Saline, Zip or ZNP rats developed massive, proteinaceous pleural effusions indicative of oxygen toxicity while ZP rats did not (0.02  ±  0.01 ml). The ratios of effusion protein to plasma protein concentration and wet/dry lung weight were also significantly reduced in ZP rats following hyperoxia.

Conclusions:  

Zymosan priming protects rats against pulmonary oxygen toxicity.