Modulation of tissue Toll-like receptor 2 and 4 during the early phases of polymicrobial sepsis correlates with mortality.
OBJECTIVE
To determine whether there was a correlation between induction of polymicrobial sepsis, modulation of tissue Toll-like receptor (TLR) gene, and protein expression and survival outcome.


METHODS
Prospective, randomized animal study.


METHODS
University medical school research laboratory.


METHODS
Age- and weight-matched ICR/HSD mice.


METHODS
Sepsis was induced by cecal ligation and puncture (CLP). No-surgery and sham (laparotomy)-operated mice were controls. We also examined tissue TLR2 and TLR4 messenger RNA and TLR4 protein levels in mice treated with an immunomodulator that increases survival in polymicrobial sepsis. In the immunomodulator study, mice were treated with glucan phosphate (50 mg/kg, intraperitoneally) 1 hr before CLP. No-surgery, sham surgery, glucan + no-surgery, sham surgery + glucan, and CLP groups were employed as controls.


RESULTS
Total RNA was isolated from liver, lung, and spleen at 0, 1, 3, 6, 8, and 24 hrs after CLP. TLR gene expression was assessed by reverse transcription-polymerase chain reaction. Tissue TLR4 protein levels were evaluated at 24 hrs by Western blot and immunohistochemistry. CLP sepsis increased (p <.05) liver and lung TLR2 and TLR4 gene expression compared with controls. TLR4 protein concentrations also were increased. Increased TLR2/4 gene and TLR4 protein expression correlated with mortality. Immunoprophylaxis with glucan phosphate increased (p <.001) long-term survival (20% vs. 70%) but inhibited (p <.05) CLP-induced increases in tissue TLR2 and TLR4 messenger RNA expression as well as TLR4 protein expression.


CONCLUSIONS
Early increases in TLR2/4 gene and TLR4 protein expression correlated with mortality, whereas blunting TLR gene and protein expression correlated with improved long-term survival. This suggests that early up-regulation of tissue TLR2/4 may play a role in the proinflammatory response and pathophysiology of polymicrobial sepsis.
Williams
David L
DL
Department of Surgery, James H. Quillen College of Medicine, East Tennessee State University, PO Box 70575, Johnson City, TN 37614-1708, USA. williamd@etsu.edu
Ha
Tuanzhu
T
Li
Chuanfu
C
Kalbfleisch
John H
JH
Schweitzer
John
J
Vogt
William
W
Browder
I William
IW
D000276:Adjuvants, Immunologic / Q000494:pharmacology; D000704:Analysis of Variance; D000818:Animals; D005786:Gene Expression Regulation / Q000187:drug effects / Q000276:immunology*; D005936:Glucans / Q000494:pharmacology; D008099:Liver / Q000378:metabolism; D008168:Lung / Q000378:metabolism; D008297:Male; D008562:Membrane Glycoproteins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008813:Mice, Inbred ICR; D016016:Proportional Hazards Models; D012333:RNA, Messenger / Q000378:metabolism; D011897:Random Allocation; D011956:Receptors, Cell Surface / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D018805:Sepsis / Q000276:immunology* / Q000401:mortality; D016019:Survival Analysis; D013997:Time Factors; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D051193:Toll-Like Receptors; D047071:beta-Glucans
D000276:Adjuvants, Immunologic; D005936:Glucans; D008562:Membrane Glycoproteins; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D051193:Toll-Like Receptors; D047071:beta-Glucans; C033363:beta-1,3-glucan