| Sepsis, the systemic inflammatory response syndrome (SIRS) induced by severe infection, is a major cause of death in the intensive care unit (ICU) patients. Delirium, an acute and fluctuating disturbance of consciousness and cognition, occurs in up to 80% of the sickest ICU populations, especially septic patients. This acute brain dysfunction is now recognized to be a significant contributor to ICU morbidity and mortality. There is, however, little evidence in regard to the prevention and treatment of septic acute cognitive impairment, and the mechanism underlying its pathogenesis remains unclear. Inflammation is considered to play an important role in the mechanism of septic cognitive complications. Urinary trypsin inhibitor (UTI; ulinastatin), a serine protease inhibitor derived from human urine, has been proved to have anti-inflammatory activity. We therefore hypothesized that UTI had a beneficial effect on the sepsis and septic acute cognitive impairment and investigated its mechanisms. Partâ… Change of cognitive function in LPS-stimulated ratsObjective: To prove that intraperitoneal (i.p.) injection of different doses of lipopolysaccharide (LPS) led to cognitive dysfunction in rats.Methods: Male Spraw Dawley rats were randomly divided into the following three treatment groups with n=15 for each group: LPS-16 group (Animals received a single i.p. injection of 16 mg/kg LPS), LPS-8 group (Animals received a single i.p. injection of 8 mg/kg LPS), NS group (Animals received a single i.p. injection of equal volume of normal saline). The cued learning test which was performed at 1, 4 and 7 hours after the LPS/NS injection.For navigation test in Morris water maze (MWM), additional 45 animals were used. The grouping method and experimental protocol were same as the above. Navigation test was performed at 1, 4 and 7 hours after the LPS/NS injection.And another 45 animals were used for open field test. The grouping method and experimental protocol were same as the above. Open field test was conducted on 0 (this was done to all the rats at 24 hours before injection), 1st, 2nd and 3rd day after the LPS/NS injection.For observing the changes of mortality, another 45 animals were used. The grouping method and experimental protocol were same as the above. The mortality was recorded at 24 hours after the LPS/NS injection.Results: In cued learning test, animals from the NS, LPS-8 and LPS-16 groups had a similar escape latency, path length and swimming speed (P > 0.05). The results in MWM test showed that at 4 and 7 hours after LPS injection, the escape latency in LPS-16 group was increased (P < 0.01 vs. NS or LPS-8 group respectively). No significant differences in the path length and swimming speed were present between the three groups (P > 0.05). The results in open field test showed that the numbers of movement and distance in the LPS-16 and LPS-8 groups were decreased significantly on 1st and 2nd day after LPS injection compared with those in NS group (P < 0.05 or <0.01 vs. NS group). The animals had longer distance and more numbers of movement on 2nd day after LPS injection in LPS-16 group than in LPS-8 group (P < 0.05 or P < 0.01). Twenty-four hours after LPS injection, 6/15 rats died in LPS-16 group (P<0.05 versus NS group), however, 0/15 rats died in LPS-8 group.Conclusion: Acute cognitive impairments occurred to rats with LPS-induced sepsis .Partâ…¡The role of inflammatory cytokines in the development of septic cognitive impairmentsObjective: To investigate the role of inflammatory cytokine TNF-alpha, IL-1beta in the development of LPS-induced septic cognitive complications.Methods: Thirty-nine male Spraw Dawley rats were randomly divided into the following three groups. The grouping procedure and experimental protocol were same as the above. The blood samples from 8 animals in each group were drawn at 4 hours after LPS or normal saline injection for detecting serum inflammatory cytokine TNF-alpha, IL-1beta, as well as neuron specific enolase (NSE) which is believed to be an indicator of brain injury, and another 5 animals were perfused and the brain samples were removed for immunohistochemical analysis of NSE after anesthesia.Results: At 4 hours after LPS injection, the serum TNF-alpha and IL-1 beta levels in LPS-8 and LPS-16 groups were increased (P < 0.05 or < 0.01, vs. NS group). The serum TNF-alpha and IL-1 beta levels in LPS-16 group were higher than those in LPS-8 group (P < 0.05). The serum NSE level in LPS-16 group was higher than that in NS and LPS-8 groups (P < 0.01). Integrated optical density (IOD) value in NSE-immunoreactivity (NSE-ir) of neurons in the hippocampal CA1 area was lower in LPS-16 group than in NS group (P < 0.01).Conclusion: Septic cognitive complication is related to abnorml changes of inflammatory cytokine TNF-alpha, IL-1beta and associated with brain injury evidenced by the increased level of serum NSE and the decreased NSE-ir of neurons in the hippocampal CA1 area.Part III Urinary trypsin inhibitor improves sepsis and septic cognitive impairmentsObjective: To prove that UTI had a beneficial effect on sepsis and septic cognitive impairments.Methods: The male Spraw Dawley rats were randomly divided into the following six groups (n=15 per group): NS+NS, NS+UTI-5, NS+UTI-20, LPS+NS, LPS+UTI-5 and LPS+UTI-20 groups. In LPS+NS, LPS+UTI-5 and LPS+UTI-20 groups, animals received a single i.p. injection of LPS at 16 mg/kg (dissolved in 1 ml NS). As the control, animals from NS+NS, NS+UTI-5 and NS+UTI-20 groups received a single i.p. injection of 1 ml NS. 30 minutes later, after this LPS or NS injection, animals from NS+UTI-5, NS+UTI-20, LPS+UTI-5 and LPS+UTI-20 groups received a single i.p. injection of 50, 200, 50 or 200 kU/kg UTI(dissolved in 1 ml NS) respectively, and animals from NS+NS and LPS+NS groups received a single i.p. injection of 1 ml NS as the control. The cued learning test which was performed at 1, 4 and 7 hours after the LPS/NS injection.For navigation test in MWM, additional 90 animals were used. The grouping method and experimental protocol were same as the above. Navigation test was performed at 1, 4 and 7 hours after the LPS/NS injection.And another 90 animals were used for open field test. The grouping method and experimental protocol were same as the above. Open field test was conducted on 0 (this was done to all the rats at 24 hours before injection) and 1st day after the LPS/NS injection.For observing the changes of mortality, another 45 animals were used. The grouping method and experimental protocol were same as the above. The mortality was recorded at 24 hours after the LPS/NS injection.Results: Twenty-four hours after LPS injection, 6/15 rats died in LPS+NS group (P<0.05 versus NS+NS group), 3/15 rats died in LPS+UTI-5 group (P=0.427 versus LPS+NS group), whereas 1/15 rat died in LPS+UTI-20 group (P=0.08 versus LPS+NS group). In cued learning test, rats from the NS+NS, NS+UTI-5, NS+UTI-20, LPS+NS, LPS+UTI-5 or LPS+UTI-20 group had similar escape latency, path length and swimming speed (P > 0.05). The results in MWM test showed that at 4 and 7 hours after LPS injection, the escape latency and swimming distance in LPS+NS group were decreased (P < 0.01 vs. NS+NS group). At 4 hours after LPS injection the escape latency and swimming distance in LPS+UTI-5 and LPS+UTI-20 groups were shorter than LPS+NS group (P < 0.01). At 7 hours after LPS injection, the escape latency and swimming distance in LPS+UTI-20 group were shorter than those in LPS+NS group (P < 0.01). At 4 and 7 hours after LPS injection, there was significant difference in the escape latency and swimming distance between the LPS+UTI-5 and LPS+UTI-20 groups (P < 0.05 or < 0.01). No statistically significant differences in the swimming speed during the test.Conclusion: UTI atteuated septic cognitive impairments, and improved the outcome of septic rats.Part IV The role of inflammatory cytokines in the protection of UTI against sepsis and septic cognitive impairmentsObjective: To investigate the role of inflammatory cytokines in the protection of UTI against sepsis and septic cognitive impairments.Methods: Seventy-eight male Spraw Dawley rats were randomly divided into the following groups: NS+NS, NS+UTI-5, NS+UTI-20, LPS+NS, LPS+UTI-5 and LPS+UTI-20 groups. In LPS+NS, LPS+UTI-5 and LPS+UTI-20 groups, animals received a single i.p. injection of LPS at 16 mg/kg (dissolved in 1 ml NS). As the control, animals from NS+NS, NS+UTI-5 and NS+UTI-20 groups received a single i.p. injection of 1 ml normal saline (NS). 30 minutes later, after this LPS or NS injection, animals from NS+UTI-5, NS+UTI-20, LPS+UTI-5 and LPS+UTI-20 groups received a single i.p. injection of 50, 200, 50 or 200 kU/kg UTI (dissolved in 1 ml NS) respectively, and animals from NS+NS and LPS+NS groups received a single i.p. injection of 1 ml NS as the control. The blood sample from 8 animals in each group was drawn at 4 hours after LPS or NS injectionfor detecting serum inflammatory cytokine TNF-alpha, IL-1beta, as well as serum NSE, and another 5 animals were perfused and the brain samples were removed for immunohistochemical analysis of NSE after anesthesia. Results: At 4 hours after LPS or NS injection, the levels of serum TNF-alpha and IL-1beta in LPS+NS group were higher than those in NS+NS group (P < 0.01). The levels of serum TNF-alpha and IL-1beta were lower in LPS+UTI-5 and LPS+UTI-20 groups than in LPS+NS group (P < 0.05, or < 0.01). Serum NSE level was increased significantly in LPS+NS group as compared to that in NS+NS group (P < 0.01). Serum NSE level was decreased significantly in LPS+UTI-5 and LPS+UTI-20 groups as compared to that in LPS+NS group (P < 0.01). Integrated optical density (IOD) value in NSE-immunoreactivity (NSE-ir) of neurons of the hippocampal CA1 area in LPS+NS group were lower than that in NS+NS group (P < 0.01). The IOD value in NSE-immunoreactivity (NSE-ir) of neurons of the hippocampal CA1 area in LPS+UTI-5 and LPS+UTI-20 groups were higher than that in LPS+NS group (P < 0.01). Conclusion: The inflammatory cytokine TNF-alpha, IL-1beta were associated with the protection of UTI against sepsis and septic cognitive impairments.ConclusionAccording to the above statements, acute cognitive impairment and brain injury occur to the septic rats evidenced by poor performance with MWM test and the increase of serum NSE level and decreased NSE-ir of neurons of the hippocampal CA1 area, which is associated with the increased levels of inflammatory cytokine TNF-alpha and IL-1beta. UTI could inhibit the increase of serum inflammatory cytokine TNF-alpha and IL-1beta levels, and reduce brain injury by decreasing serum NSE level and improving IOD value in NSE-ir of neurons of the hippocampal CA1 area, thus had beneficial effect on the septic acute cognitive impairment. |
PDF Full Text Request