The spleen modulates the febrile response of guinea pigs to LPS

The febrile responses of splenectomized (Splex) or sham-operated (Sham) guinea pigs challenged intravenously or intraperitoneally with lipopolysaccharide (LPS) 7 and 30 days after surgery were evaluated. FITC-LPS uptake by Kupffer cells (KC) was additionally assessed 15, 30, and 60 min after injection. LPS at 0.05 microg/kg iv did not evoke fever in Sham animals but caused a 1.2 degrees C core temperature (T(c)) rise in the Splex animals. LPS at 2 microg/kg iv induced a 1.8 degrees C greater T(c) rise of the Splex animals than of their controls. LPS at 2 and 8 microg/kg ip 7 days postsurgery induced 1.4 and 1.8 degrees C higher fevers, respectively, in the Splex than Sham animals. LPS at 2 and 8 microg/kg ip 30 days postsurgery also increased the febrile responses of the asplenic animals by 1.6 and 1.8 degrees C, respectively. FITC-LPS at 7 days was detected in the controls within KC 15 min after its administration; the label density was reduced at 30 min and almost 0 at 60 min. In the Splex group, in contrast, the labeling was significantly denser and remained unchanged through all three time points; this effect was still present 30 days after surgery. Similar results were obtained at 60 min after FITC-LPS intraperitoneal injection. Gadolinium chloride pretreatment (-3 days) of the Splex group significantly reduced both their febrile responses to LPS (8 microg/kg ip) and their KC uptake of FITC-LPS 7 days postsurgery. Thus splenectomy increases the magnitude of the febrile response of guinea pigs and the uptake of systemically administered LPS.     

Blunted febrile response to intravenous endotoxin in starved rats

The effects of fasting on the febrile responses to intravenous injection of bacterial lipopolysaccharide (LPS; endotoxin) of Escherichia coli were investigated in rats. Ad libitum-fed rats (C) produced a biphasic fever with an increase in the temperature difference between brown adipose tissue and colon and shivering activity (SA). Measurement by a direct calorimeter showed no particular changes in heat loss. Rats starved for 4 days (F4) responded to intravenous LPS with a monophasic fever accompanied by an increase in SA only. However the maximal rise in colonic temperature (Tco) did not differ from C rats. Subsequent 2-day fasting reduced SA and the maximal fever height. Endogenous pyrogen (EP) injected intravenously produced a prompt rise in Tco followed by prolonged hyperthermia in C rats. In the F4 rats, there was no such sustained rise in Tco as a result of intravenous EP. The response in Tco to intravenous prostaglandin E2 (PGE2) was the same in fed and starved rats. The administration of LPS, EP, and PGE2 into the lateral ventricle evoked a similar extent of hyperthermia in C and F4 rats. Because the second phase of fever has been shown to occur after pyrogens are translated into a febrile stimulus within the blood-brain barrier, it is assumed that the functional changes of the blood-brain barrier such as in the permeability of pyrogens or in the sensitivity of pyrogen receptors resulted in the absence of the second phase of fever in starved rats.     

Kupffer cell-generated PGE2 triggers the febrile response of guinea pigs to intravenously injected LPS

Because the onset of fever induced by intravenously (i.v.) injected bacterial endotoxic lipopolysaccharides (LPS) precedes the appearance in the bloodstream of pyrogenic cytokines, the presumptive peripheral triggers of the febrile response, we have postulated previously that, in their stead, PGE2 could be the peripheral fever trigger because it appears in blood coincidentally with the initial body core temperature (Tc) rise. To test this hypothesis, we injected Salmonella enteritidis LPS (2 microg/kg body wt i.v.) into conscious guinea pigs and measured their plasma levels of LPS, PGE2, TNF-alpha, IL-1beta, and IL-6 before and 15, 30, 60, 90, and 120 min after LPS administration; Tc was monitored continuously. The animals were untreated or Kupffer cell (KC) depleted; the essential involvement of KCs in LPS fever was shown previously. LPS very promptly (<10 min) induced a rise of Tc that was temporally correlated with the elevation of plasma PGE2. KC depletion prevented the Tc and plasma PGE2 rises and slowed the clearance of LPS from the blood. TNF-alpha was not detectable in plasma until 30 min and in IL-1beta and IL-6 until 60 min after LPS injection. KC depletion did not alter the times of appearance or magnitudes of rises of these cytokines, except TNF-alpha, the maximal level of which was increased approximately twofold in the KC-depleted animals. In a follow-up experiment, PGE2 antiserum administered i.v. 10 min before LPS significantly attenuated the febrile response to LPS. Together, these results support the view that, in guinea pigs, PGE2 rather than pyrogenic cytokines is generated by KCs in immediate response to i.v. LPS and triggers the febrile response.     

Escherichia coli lipopolysaccharides produce serotype-specific hypothermic response in biotelemetered rats

We investigated whether LPS-induced hypothermia develops in a serotype-specific manner in biotelemetered conscious rats. Two different Escherichia coli serotypes of LPSs were injected at a dose of 250 mug/kg ip. E. coli O55:B5 LPS elicited an initial hypothermia and subsequent fever, but E. coli O111:B4 LPS caused more potent monophasic hypothermia. Serum tumor necrosis factor (TNF)-alpha levels were dramatically elevated at the initial phase of the hypothermia induced by both LPSs. This elevation tended to subside at the nadir of E. coli O55:B5 LPS-induced response but progressively increased at the nadir of E. coli O111:B4 LPS hypothermia. Serum IL-10 levels were moderately elevated at the initial phase of the hypothermia and persisted at the same level at the nadir of each LPS-induced response. No change was observed at the serum IL-18 levels. A selective cyclooxygenase (COX)-1 enzyme inhibitor, valeryl salicylate (20 mg/kg sc), abolished the hypothermia without any effect on the elevated cytokine levels. Another COX-1-selective inhibitor, 5-(4-chlorophenyl)-1-(4-methoxyphenyl)-3-(trifluoromethyl)-1H-pyrazole (SC-560; 1 mg/kg sc) inhibited hypothermic responses as well. Meanwhile, cytokine levels were also reduced by SC-560 treatment. These findings suggest that LPS-induced hypothermia may have serotype-specific characteristics in rats. E. coli O111:B4 LPS has more potent hypothermic activity than E. coli O55:B5 LPS; that may presumably be related to its higher or sustained capability to release antipyretic cytokines, such as TNF-alpha. COX-1 enzyme may be involved in the generation of the hypothermia, regardless of the type of LPS administered.     

大肠埃希菌脂多糖诱导的血小板降解及急性休克:O抗原在LPS诱导的免疫反应中的作用

目的探讨LPS中的0抗原部分与其它部分在血小板反应中的作用。方法给BALB／c小鼠注人大肠埃希菌野生株E．coli O8、O9、K-12（不含有O抗原）及2株重组变异的K-12株（携带编码O8、O9的O抗原rfb基因）。结果K-12的LPS引起血小板反应及急性休克能力较弱,O8及O9引起一定的反应,而这2种重组的LPS,即在K-12的LPS上带有O8或O9的O抗原．显示出极强的活性。静脉注入补体C5的阻止剂后,重组株LPS的作用消失了。而且在缺乏补体C5小鼠DBA／2中,重组的LPS能引起血小板的聚集但不能降解,也不能引起休克症状。结论诱导血小板反应及急性休克的能力依赖于LPS结构;O抗原及R核心抗原是表现活性的必要结构;LPS诱导的血小板反应及急性休克依赖补体系统。     

Attenuated febrile response to lipopolysaccharide in rats with biliary obstruction

Patients with biliary tract obstruction have unexplained, inordinately high rates of perioperative morbidity and mortality, whereas cholestatic animals display abnormal hypothalamic responses to pyrogenic stimuli. We asked if obstructive cholestasis was associated with abnormal fever generation. Male Sprague-Dawley rats (250 g) underwent laparotomy for implantation of thermistors and either bile duct resection (BDR) or sham operation. After recovery, temperatures were recorded by telemetry and conscious, unrestrained rats in each group were injected intraperitoneally with either interleukin-1beta (IL-1beta;1 microg/kg) or Escherichia coli lipopolysaccharide (LPS; 50 microg/kg). Baseline temperatures in both groups were similar. Febrile responses after IL-1beta injection in BDR and sham groups were not significantly different. However, in response to LPS injection, BDR rats showed an initial hypothermia with a subsequently attenuated febrile response. Administration of anti-tumor necrosis factor-alpha (TNF-alpha) antibody 2 h before LPS injection blocked the LPS-induced hypothermia seen in BDR animals. However, serum levels of TNF-alpha were not significantly different between sham and BDR animals after LPS injection at any time point measured (0, 1.5, and 3 h).     

Cytokine response to Escherichia coli in gnotobiotic pigs

One-week-old-germ-free pigs were inoculated with 10(8) CFU of E.coli bacteria-either commensal 086 strain or virulent 055 strain for 1 d. Bacteria were counted in the small intestine, mesenteric lymph nodes, blood and lungs. The O55 strain reached higher levels in circulation and lungs. IL-8, IL-10 and TNF-alpha concentrations were determined by ELISA in plasma and intestinal washes . No difference in cytokine levels was found between control germ-free pigs and their counterparts associated with commensal O86 strain in spite of its high concentration in the gut and circulation.     

Increased neural damage to global hemispheric hypoxic ischemia (GHHI) in febrile but not nonfebrile lipopolysaccharide Escherichia coli injected rats

Experiments were conducted to compare the impact of febrile versus nonfebrile lipopolysaccharide (LPS) induced bacterial infection at the time of global hemispheric hypoxic ischemia (GHHI) on the neural damage evoked by the GHHI insult. In the first study acute intraperitoneal (i.p.) sterile saline (SS) or LPS Escherichia coli (60 microg/kg) was given to groups of male, conscious Long Evans rats, and core (colonic, Tc) temperatures were monitored over 6 h postinjection. Peak febrile response occurred approximately 5 h after the LPS E. coli was injected. Upon sacrifice 7 days later, no hemispheric or regional brain damage occurred in the saline or LPS-injected groups of this first study. In the second study, GHHI was applied (ligation of right common carotid artery + 35 min of 12% O2) in groups of anesthetized, male Long Evans rats previously given an acute i.p. injection of sterile saline or 60 microg/kg LPS E. coli 5 h earlier. Temperatures (Tc) were monitored before, during, and 1.5 and 24 h following GHHI. The LPS-injected group was subdivided into a febrile (Tc > 38 degrees C before and (or) after GHHI) and nonfebrile (Tc < 38 degrees C before and after GHHI) subgroups. A significant correlation was found between the peak temperature rise from preinjection control values following drug administration of either saline or LPS E. coli and the resultant hemispheric damage caused by GHHI. Moreover, upon sacrifice 7 days later ipsilateral hemispheric and regional (i.e., hippocampal, thalamic) damage to GHHI of the febrile LPS E. coli group was significantly increased from respective hemispheric, hippocampal, and thalamic damage of the saline and nonfebrile, LPS groups given the same ischemic insult. Results suggest that the heightened Tc of a LPS infection at the time of global ischemia exacerbated the neural damage of GHHI, a finding similar to that reported with heightened core temperatures induced by external heating.     

Cell response of Escherichia coli to cisplatin-induced stress

Cisplatin is undoubtedly one of the most common and successful anticancer drugs worldwide. Though its DNA-based mechanism of action is well established, the contribution of the proteome to this process remains unclear. The possible impact of particular Escherichia coli proteins on the cytostatic activity of cisplatin was the subject of this study. Our main focus was not only the "bottom-up" identification of novel cisplatin protein targets through LC/LC-MS/MS analysis, but also a label-free quantification of their regulation profile by spectral-counting. The regulation of two proteins, aconitate hydratase 2 and 60 kDa chaperonin 1, could be linked to a platinated amino acid in the protein sequence, whereas in the cases of 30S ribosomal protein S1 and enolase, it could be shown that cisplatin fragments are coordinated to an essential site for the functionality of the protein. Nucleoside triphosphate pyrophosphohydrolase (MazG) regulates the programmed cell death and was found to be platinated on the protein surface, which probably correlates with the established mode of action. A possible new chapter in the understanding of cisplatin's mechanism of action and its severe side effects is opened, since evidence is provided that platinated proteins are not only involved in cellular stress response but also in energy metabolism through glycolysis and catabolic processes, in gene regulatory mechanisms and protein synthesis.     

Cold shock response in Escherichia coli

Sensing a sudden change of the growth temperature, all living organisms produce heat shock proteins or cold shock proteins to adapt to a given temperature. In a heat shock response, the heat shock sigma factor plays a major role in the induction of heat shock proteins including molecular chaperones and proteases, which are well-conserved from bacteria to human. In contrast, no such a sigma factor has been identified for the cold shock response. Instead, RNAs and RNA-binding proteins play a major role in cold shock response. This review describes what happens in the cell upon cold shock, how E. coli responds to cold shock, how the expression of cold shock proteins is regulated, and what their functions are.     

Metabolic response to starvation in late pregnant rats. I. Maternal response

The aim of the present study was to examine effect of prolonged fasting on muscle glycogen and triglyceride concentration as well as on non-protein nitrogen excretion with urine in late pregnant rats. They were divided into four groups: I--fed, pregnant for 21 days, II--fasted for one day (from 20 to 21 day of pregnancy), III--fasted for two days (from 19 to 21 day) and IV--fasted for three days (from 18 to 21 day). The concentration of glycogen and triglycerides was determined in the following tissues: the white and red layers of the vastus lateralis, the soleus, the diaphragm, the heart and the liver. The urine was collected in each group 24 h (from 20 to 21 day). It has been found that concentration of glycogen in the leg muscles is reduced by about 50% and in the diaphragm by 75% already after 24 h fasting and then remains stable. The concentration of glycogen in the heart increases after one day of fasting and then returns to the control value. The effect of fasting on the concentration of triglycerides in the tissues depends on a tissue studied. It decreases gradually in the white vastus, and in the soleus only on the third day. It is elevated during the first two days of fasting in the red vastus, diaphragm and liver and returns to the control level on the third day. The fasting doubled the concentration of triglycerides in the heart. The urinary urea, creatinine, and uric acid excretion decreases and ammonia excretion increases during fasting. The results obtained indicate that the late gestation does not alter response of muscle glycogen metabolism to fasting as compared to the male rats. It does effect metabolism of triglycerides.     

Metabolic response to starvation in late pregnant rats. II. Fetal response

Effect of prolonged maternal fasting on the fetal liver and heart glycogen and triglyceride content and on concentration of glucose, urea, uric acid and alpha amino-nitrogen in the amniotic fluid has been studied in rats. The animals were divided into four groups: fed (control), fasted for one day (from 20 to 21 day of pregnancy), fasted for two days (from 19 to 21 day) and fasted for three days (from 18 to 21 day). Maternal fasting for two and three days resulted in reduction in fetal growth. The fetal liver glycogen content was reduced already after one day of fasting, stabilized after two days and then further decreased after three days. The fetal heart glycogen content was reduced only after three days of fasting. The fetal liver triglyceride content increased gradually during the first two days of fasting and then stabilized. The content of triglycerides in the heart was elevated after two and three days of food deprivation. The amniotic fluid glucose concentration decreased after one day of fasting and then stabilized. Fasting did not effect the concentration of the nitrogenous compounds in the amniotic fluid. It is concluded that maternal fasting affects markedly metabolism of energy substrates stored in the fetal liver and the heart and the composition of the amniotic fluid.