The Effects of Steroid and Lidocaine on Inflammatory Responses in the Rabbit Lung of Induced Endotoxemia

Lim, Yong Gul; Kang, Yoo Jin; Kim, Dae Woo; Cho, Won Sun

Abstract

Background: It has been reported that steroid and lidocaine reduce inflammatory responses to endotoxin. The aim of this study is to compare the effects of lidocaine with those of steroid on inflammatory responses to Escherichia coli endotoxemia in the rabbit lung.
Methods
Twenty four animals were randomly assigned to one of four groups. Group I (endotoxemic group; control, n=6): They were received E. coli endotoxin (500 microg/kg) intravenously through the ear vein and followed by saline infusion at 20 ml/kg/hr for 4 hours. Group II (steroid treated group, n=6): They were treated with steroid (30 mg/kg) intravenously just after endotoxin injection and then saline was given at 20 ml/kg/hr for 4 hours. Group III (lidocaine treated group, n=6): They were received same as the endotoxemic group and lidocaine (3 mg/kg IV bolus, then continuous infusion at the rate of 2 mg/kg/hr) was administered with saline at 20 ml/kg/hr for 4 hours. Group IV (steroid & lidocaine treated group, n=6): They were received same as the endotoxemic group and after endotoxin infusion, steroid (30 mg/kg) and lidocaine (3 mg/kg IV bolus, then continuous infusion at the rate of 2 mg/kg/hr) was administered intravenously with saline. Numbers of neutrophils and monocytes in the samples of peripheral blood and lung tissue were counted and compared to evaluate the anti-inflammatory effect of drugs.
Results
The group II, III, and IV showed significant attenuation of inflammatory responses compared to group I in the rabbit lung(P<0.05). But there were no significant differences among group II, III, and IV. There was no additive effect between steroid and lidocaine.
Conclusion
These results suggest that lidocaine could be used as an alternative drug to steroid for its anti-inflammatory effects and cost-effectiveness.