Parallel Self-Induction of TNF-α and Apoptosis in the Thymus of Mice after Burn Injury

Author： Cho K. Adamson L.K. Greenhalgh D.G.

ISSN： 0022-4804

Source： Journal of Surgical Research, Vol.98, Iss.1, 2001-06, pp. : 9-15

Disclaimer: Any content in publications that violate the sovereignty, the constitution or regulations of the PRC is not accepted or approved by CNPIEC.

Previous Menu Next

Abstract

Background. Burn injury often causes multiple organ failure as well as skin damage. Several studies suggest that TNF-α plays an important role in postinjury immunosuppression by altering lymphoid tissues. We investigated the regulation of TNF-α expression and apoptosis in the spleen and thymus of mice after burn injury.Materials and methods. C57BLKS/J mice were subjected to 18% TBSA full-thickness burn and the spleen and thymus were harvested at various time points (3 h to 29 days). The expression of TNF-α mRNA and protein in tissue extracts was analyzed by RT-PCR and ELISA. Apoptosis was measured by flow cytometry using annexin V staining.Results. Burn injury induced TNF-α mRNA expression in the thymus at Day 1 and it returned to the basal levels at Day 14 and thereafter. Similarly, TNF-α mRNA up-regulation peaked between Day 1 and Day 3 in the spleen. Induction of TNF-α protein peaked at Day 1 in the thymus, whereas, TNF-α protein was unchanged in the spleen after burn injury. There was a twofold increase in apoptotic cells at Day 1 in the thymus, which is consistent with mRNA and protein data. In contrast, burn injury did not change apoptotic events in the spleen.Conclusions. The parallel induction of TNF-α mRNA, TNF-α protein, and apoptosis suggests that TNF-α may contribute to immunosuppression after burn injury by inducing apoptosis in the thymus.