Exogenous heat shock protein 70 mediates sepsis manifestations and decreases the mortality rate in rats

Abstract

Mammalian responses to bacterial lipopolysaccharide (LPS) from the outer membrane of Gram-negative bacteria can lead to an uncontrolled inflammatory reaction that can be deadly for the host. We checked whether heat shock protein 70 (Hsp70) protein is able to protect animals from the deleterious effects of bacterial LPS by monitoring the effect of exogenous Hsp70 injections before and after LPS administration. Our research with rats demonstrates for the first time that administration of exogeneous Hsp70 before and after LPS challenges can reduce mortality rates and modify several parameters of hemostasis and hemodynamics. Hsp70 isolated from bovine muscles showed significant protective effects against the impaired coagulation and fibrinolytic systems caused by LPS, and reduced the mortality caused by Escherichia coli and Salmonella typhimurium LPS injections significantly. Characteristically, Hsp70 preparations used in the experiments result in different effects when administered before and after an LPS challenge, and the effects of Hsp70 injections also differ significantly depending on the origin of the LPS (E coli vs S typhimurium). Based on our data, mammalian Hsp70 appears to be an attractive target in therapeutic strategies designed to stimulate endogenous protective mechanisms against many deleterious consequences of septic shock by accelerating the functional recovery of susceptible organs in humans.

Fig 1.

Effects of Hsp70 on LPS-induced mortality in rats. (A) The influence of Hsp70 preparations administration per se on mortality. 1, NaCl has been injected; 2, Hsp70-ND has been injected; 3, Hsp70-DT has been injected. (B) The influence of Hsp70 preparation administration on E coli LPS-induced mortality. 1, NaCl has been injected 10 minutes before LPS challenge; 2, Hsp70-ND has been injected 10 minutes before LPS challenge; 3, Hsp70-DT has been injected 10 minutes before LPS challenge; 4, Hsp70-DT has been injected 10 minutes after LPS challenge. (C) The influence of Hsp70 preparation administration on S typhimurium LPS-induced mortality. 1, NaCl has been injected 10 minutes before LPS challenge; 2, Hsp70-ND has been injected 10 minutes before LPS challenge; 3, Hsp70-DT has been injected 10 minutes before LPS challenge; 4, Hsp70-DT has been injected 10 minutes after LPS challenge

Fig 2.

Changes of hemostasis parameters after administration of Hsp70-ND and Hsp70-DT preparations of Hsp70 (dose, 266 μg/kg). 1, NaCl (0.9%) (n = 4); 2, Hsp70-DT (n = 6); 3, Hsp70-ND (n = 6). *P < 0.05 using Wilcoxon test

Fig 3.

Changes in mean arterial pressure (MAP) (A) and heart rate (B) after administration of Hsp70-ND and Hsp70-DT preparations of Hsp70 (dose, 266 μg/kg). *Indicates statistically significant differences (using ANOVA 2 method) between groups 1 and 3. ^#Indicates statistically significant differences (using ANOVA 2 method) between groups 2 and 3

Fig 4.

Changes of hemostasis parameters due to administration of E coli LPS (dose, 2 mg/kg) depending on concomitant introduction of Hsp70 preparations. 1, E coli LPS (n = 10); 2, Hsp70-ND plus E coli LPS (n = 10); 3, Hsp70-DT plus E coli LPS (n = 10); 4, E coli LPS plus Hsp70-DT (n = 9). *P < 0.05 using Wilcoxon test

Fig 5.

Patterns of mean arterial pressure (MAP) (A) and heart rate (B) after administration of E coli LPS only (group 1) and resulting from prophylactic action of Hsp70-ND (group 2) and Hsp70-DT (group 3); and patterns of MAP (C) and heart rate (D) after administration of E coli LPS (group 4) and after therapeutic administration of Hsp70-DT introduced after E coli LPS injection (group 5). *Indicates statistically significant differences (using ANOVA 2 method) between groups 1 and 2. ^#Indicates statistically significant differences (using ANOVA 2 method) between groups 1 and 3. **Indicates statistically significant differences (using ANOVA 2 method) between groups 4 and 5

Fig 6.

Changes of hemostasis parameters due to administration of S typhimurium LPS (dose, 4 mg/kg) depending on concomitant introduction of Hsp70 preparations. 1, S typhimurium LPS (n = 10); 2, Hsp70-ND plus S typhimurium LPS (n = 10); 3, Hsp70-DT plus S typhimurium LPS (n = 10); 4, S typhimurium LPS plus Hsp70-DT (n = 9). *P < 0.05 using Wilcoxon test

Fig 7.

Changes in mean arterial pressure (MAP) (A) and heart rate (B) after administration of S typhimurium LPS (group 1) and after preliminary administration of Hsp70-ND (group 2) and Hsp70-DT (group 3); and patterns of MAP (C) and heart rate (D) after administration of S typhimurium LPS (group 4) and after therapeutic administration of Hsp70-DT introduced 10 minutes after S typhimurium LPS injection (group 5). *Indicates statistically significant differences (using ANOVA 2 method) between groups 1 and 3. **Indicates statistically significant differences (using ANOVA 2 method) between groups 4 and 5

Fig 8.

Concentration of Hsp70 in the blood of experimental Wistar rats after administration of exogenous Hsp70 at the dose of 266 μg/ kg. *Significant differences between control (NaCl) and experimental groups