TNF-α: a possible mediator of remote tissue injury after viper envenomation

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Introduction

TNF is a potent inflammatory promoting agent that can potentiate organ and tissue injury. A possible role of TNF in causing local tissue damage following snakebite was recently demonstrated in an intact rat model. We compared the systemic effects of TNF on the hearts and lungs of rats following an intramuscular injection of a sub-lethal dose of Vipera asis venom (500 μg/kg, experimental groups) to equivalent injections of saline (control group).

Results

Systemic TNF activity, heart rate and blood pressure as well as lung permeability and neutrophil sequestration were then evaluated in both groups. The venom caused a significant reduction in heart rate and arterial blood pressure, and the serum TNF levels peaked after two hours. These values remained unchanged in the control group. In contrast, lung microvasculature permeability and neutrophil sequestration were not significantly different between the experimental and control groups.

Conclusions

This study of the systemic and inflammatory effects of Vipera aspis venom showed that intramuscular injection of the poison results in systemic effects that are possibly mediated in part by TNF. These findings may have therapeutic implications in the treatment of patients with severe systemic manifestations after snakebites in terms of the possible benefits of blocking TNF activity.