C1q content of serum and lung lavage fluid of rats exposed to toxic levels of oxygen.
We used a sensitive hemolytic assay to measure the level of C1q, a subcomponent of the first complement protein in the classic pathway, in bronchoalveolar lavage fluid and serum of rats exposed to air and hyperoxia. The serum level was 125 +/- 5 micrograms/ml and the lavage level was 41 +/- 17 ng/ml in rats breathing air. In rats exposed to acute oxygen toxicity (95% O2 for 66 hr), the serum level was at 107 +/- 10 micrograms/ml, but the level in lavage fluid increased to 2457 +/- 400 ng/ml (p less than 0.05 compared to air). Administration of the proline analogue cis-4-hydroxy-L-proline to air- and O2-exposed rats reduced the serum C1q level by 28% and 34%, respectively (both p less than 0.05), presumably by interfering with metabolism of the collagen-like sequence of C1q. The level of C1q in bronchoalveolar lavage fluid is a sensitive marker of acute lung injury.
D000818:Animals; D003166:Complement Activating Enzymes / Q000032:analysis*; D015922:Complement C1q; D006909:Hydroxyproline / Q000008:administration & dosage / Q000494:pharmacology; D007279:Injections, Subcutaneous; D007958:Leukocyte Count; D008168:Lung / Q000166:cytology / Q000187:drug effects* / Q000276:immunology; D008297:Male; D009504:Neutrophils / Q000502:physiology; D010100:Oxygen / Q000494:pharmacology / Q000633:toxicity*; D051381:Rats; D011919:Rats, Inbred Strains; D012709:Serum Albumin / Q000032:analysis; D007507:Therapeutic Irrigation
D012709:Serum Albumin; D015922:Complement C1q; D003166:Complement Activating Enzymes; D006909:Hydroxyproline; D010100:Oxygen