Experimental study on setting up hypercapnic model and its pathophysiological changes in rats

AIM:To reproduce hypercapnic models and approach some pathophysiological changes in rats. METHODS:The mixed gases of high concentrated carbon dioxide (8% CO₂, 21% O₂, 71% N₂) were given to wistar rats 7 hours a day for 28 days. The various indexes were compared between control group (group A) and hypercapnic group (group B). RESULTS:The PaCO₂ and the lipid peroxides (LPO) contents in plasma, lung tissue and right ventricle were significantly higher in group B than those in group A (P＜0.05 ); while artery pH values (7.205±0.037) and superoxide dismutase (SOD) activities in erythrocytes, lung tissue and right ventricle were significantly decreased in group B compared with group A (P＜0.05). The weight of right ventricle was significantly heavier than that of group A (P＜0.05). There were no significant differences were found in mean right artial pressure (Rap), mean right ventricle pressure (Rvp) and mean pulmonary artery pressure (Pap) between both groups.CONCLUSION:Hypercapnic model can be reproduced with 8% CO₂ mixed gases in rats. High concentration of CO₂ can cause a series of positively toxic injuries to the body. Care should be seriously taken when using permissive hypercapnic ventilation in the clinic.