Up-Regulation of Toll-Like Receptors 2 and 4 on Peripheral Monocytes After Major Abdominal Surgical Operation

Abstract

This study is to investigate the time-course expression of TLR2 and TLR4 on peripheral monocytes in patients receiving major abdominal surgical operation. Blood samples were obtained from peripheral vein before and after an operation in 30 patients with gastrointestinal or pancreatic surgery. The mRNA expression of TLR2, TLR4, TNF-α and IL-6 on peripheral blood mononuclear cells (PBMC) was analyzed by real-time PCR. The expressions of TLR2, TLR4, HLA-DR, CD80, and CD86 on monocytes were analyzed by flow cytometry. The expressions of TLR2 and TLR4 on monocytes responding to each agonist (zymosan and lipopolysaccharide) were also measured by flow cytometry. TLR2 and TLR4 mRNA showed significant up-regulation after the completion of the operation when compared with those before the operation. TLR2 expression reached its peak level on day 1 and TLR4 on days 1 and 3. There was no significant difference between pre- and post-operation in the expressions of HLA-DR, CD80 and CD86. Stimulation with zymosan, increased the expression of TLR2 significantly after the operation and reached its highest value on day 3. Similarly, after stimulation with lipopolysaccharide, the expression of TLR4 was also increased and the highest level was observed on day 1. The expression of TNF-α and IL-6 mRNA decreased after completion of the operation and gradually returned to basal level. The expressions of TLR2 and TLR4 on monocytes were up-regulated during the early period after a major abdominal surgical operation in patients, which might be related to the activation of innate immunity.