The effect of endotoxin on murine stem cells

Previous studies showed that after 5 μg of Salmonella typhosa endotoxin there was an increase in colony stimulating factor temporally related to a fall in murine marrow in vitro colony forming cells (CFC). This was followed by differentiation along the marrow granulocytic pathway. The present studies showed that after 5 μg of endotoxin the peripheral blood CFC fell by approximately 50% at one hour, rose to a level ten fold that of control at six hours and then returned to control values by 48 hours. There was a progressive increase in the number of splenic CFC to ten fold that of control from 24 to 72 hours after endotoxin. These data imply a migration of CFC from the marrow to the spleen along with an in-situ increase in splenic CFC. Thus, either migration or differentiation may explain the fall in marrow CFC after endotoxin. Spleen colony forming units (CFU) in the marrow were measured by a transplantation technique and the transplantation fraction (f Fx) determined. A decrease in marrow CFU at 24 hours after endotoxin was secondary to a change in the f Fx. from 11.1% to 7.6%. There was however, an increased percentage of CFU in DNA synthesis in the interval of 6–48 hours after endotoxin, as judged by the hydroxyurea technique. As the marrow CFC fell within 20 minutes of endotoxin administration, the data suggest the CFC may be affected initially and that changes in the generative cycle of the CFU may be of a secondary nature.     

The effect of the glucocorticoid Oradexon on endotoxin-induced peritoneal cell response

Glucocorticoids are important modulators of immune reactions. They are capable of antagonising several effects of the bacterial endotoxin by inhibiting endotoxin-induced leukocyte activation, and the production of cytokines and inflammatory mediators. We earlier demonstrated that the antiglucocorticoid RU 38486 enhances the cytokine production induced by endotoxin and aggravates the course of experimental endotoxic and septic shock. In the present study we investigated the effect of the glucocorticoid Oradexon on the endotoxin-induced peritoneal cell response. For measurement of the peritoneal cell response, male CFLP mice (20-25 g) were injected i.p. with 10 microg/10 g body weight endotoxin (E. coli 026:B6 LPS, Difco Lab, Detroit, lot 110273JB). Dexamethasone (Oradexon, N.V, Organon Oss, The Netherlands) was administered i.p., i.v. or s.c. in a dose of 0.1 mg/10 g body weight, alone or concomitantly with endotoxin. We found that bacterial endotoxin increased the total cell count due to neutrophilia at 24 hours and, due to increases in the number of macrophages and lymphocytes 48 and 72 hours after treatment, respectively. The i.p., i.v., and s.c. injection of Oradexon, increased the total cell count and the macrophage count at 24, 48 and 72 hours. The i.p., s.c. and i.v. injection of Oradexon, concomitantly with endotoxin, reduced the total cell count at 48 and 72 hours, due to decreases in the macrophage count. The i.p., i.v. or s.c. administration of Oradexon concomitantly with LPS decreased the lymphocyte count and the neutrophil count at 24 and 72 hours. These results prove that glucocorticoids are capable of modifying the immune cell reactions induced by endotoxin.     

Serum trypsin inhibitor activity in rabbits immunized with mounting doses of bacterial antigen (Salmonella paratyphi B)

The author studied changes in serum trypsin inhibitor activity and in the leucocyte count in rabbits immunized withSalmonella paratyphi B vaccines in different concentrations. Changes in serum trypsin inhibitor activity followed a regular course. Six hours after administering the antigen it fell significantly, the degree of the decrease being correlated to the antigen concentration. After 24, 48, 72 and 96 hours it was significantly raised, the maximum increase being recorded after 72 hours; the increase was likewise correlated to the vaccine concentration. Pronounced changes were also recorded in the leucocyte count, but these did not follow a regular course and were not correlated to the amount of antigen administered.     

Plasma renin, renin substrate and angiotensin II changes following experimental endotoxinaemia.

The effect of a single dose of endotoxin (B. coli, 1.5 mg/kg intravenously) on plasma renin concentration (PRC), renin substrate (PRSC), and angiotensin II (AT II) was studied in rats over a period of 48 hours. All determinations were performed by specific radioimmunoassay. Six and nine hours following endotoxin administration, renin secretion was decreased, whereas at 48 hours a slight increase in the PRC was found. In contrast, a three-fold elevation of the PRSC occurred during the first 24 hour period, attributable to a stimulation of the hepatic biosynthesis as result of corticosterone oversecretion. According to the observed changes in PRC and PRSC, AT II remains unchanged after six and nine hours, whereas a significant increase was detected after 24 and 48 hours. Based on the actual AT II level, the findings emphasize that in the rat the RAS does participate in the later stages of endotoxin stress only.     

Hematological and Blood Biochemical Effects of Fasting and Subsequent Oral Administration of Endotoxin in Prepubertal Gilts

The main objective of the present study was to investigate the effects of short-term fasting in gilts on endocrinological and blood biochemical parameters and, further, the effects of subsequent oral endotoxin (ET) administration. Group 1 was fasted for 30 h and then received feed with ET added. Group 2 was fasted for 30 h but received standard feed at refeeding. In group 3, gilts were fed every 6 h for 30 h. The major effects of fasting were: gradually increased concentration of plasma prostaglandin F2α metabolite, serum total bilirubin, serum free fatty acids, and decreased serum glucose. The values were normalized within 1–4 h of refeeding. Twelve hours after refeeding, the ET-refed gilts showed higher levels of serum total bile acids and polymorphonuclear leukocytes than those in group 2. It is possible that the observed changes during fasting reflect either an increased intestinal uptake of naturally present endotoxin or a reduced endotoxin detoxifying capacity of the liver. The increased bile acid concentration and polymorphonuclear leukocyte count following refeeding with ET-feed may indicate that orally administered ET is to some extent absorbed from the gut.     

Hirulog effect in rat endotoxin shock

Hirulog^TM is a thrombin catalytic site inhibitor which exhibits specificity for the anionic binding exosite of alpha thrombin. Here, we have evaluated the effect of Hirulog^TM (1, 5 and 10 mg/kg, 30 min pretreatment) in a rat model of endotoxemia. Intravenous injection of lipopolysaccharide from E. coli (25 mg/kg; serotype 0127:B8) caused decreases in blood pressure which were significantly reduced (about 60%) in animals pretreated with Hirulog^TM. Rat survival to endotoxin was significantly increased in Hirulog^TM pretreated group (5 and 10 mg/kg) up to 24 hours. Hirulog^TMat the dose of 10 mg/kg inhibited both endotoxin-induced leukopenia at 30 and 60 minute points and thrombocytopenia at 30 minute point but not at 90 and 120 minute points. Fibrinogen levels were significantly reduced after 2 hours following endotoxin administration. Pretreatment with Hirulog^TM (5–10 mg/kg i.v.) 30 min prior to administration of endotoxin prevented changes in fibrinogen plasma levels. These results demonstrate that Hirulog^TM-induced inhibition of thrombin is effective in reducing toxic and lethal effects of endotoxin.     

Activities of conjugating and antioxidant enzymes following endotoxin exposure

Endotoxin exposure elicits various responses in mammals including the acute phase response that has been shown to cause changes in the activity of several forms of cytochrome P450s and other enzymes. Therefore, the hepatic conjugating enzyme, glutathione S‐transferase (GST), and UDP‐glucuronosyltransferase (UDPGT), the antioxidant enzymes, glutathione peroxidase (GSHPx), catalase, and superoxide dismutase (SOD), as well as lipid peroxidation were investigated following the administration of endotoxin to male Sprague–Dawley rats (8 mg/kg body weight). Rats were euthanized at various times following endotoxin administration and the livers removed and processed to assess various enzyme activities. Glutathione S‐transferase, UDPGT, and GSHPx activity showed statistically significant decreases after 24 hours and remained lower than controls for the duration of the study. Decreases in total SOD and catalase activities were seen at 24, 48, and 72 hours following endotoxin administration; however, only catalase activity showed statistically significant differences between control and treated samples at those time points, and total SOD activity showed a statistically significant decrease at 24 hours. No statistically significant changes were seen in the level of lipid peroxidation in the liver microsomes from endotoxin‐treated animals. Changes in the conjugative enzymes and the free‐radical scavenging enzymes following endotoxin exposure may alter the host's metabolism and response to free radicals. © 1998 John Wiley & Sons, Inc. J Biochem Toxicol 13: 63–69, 1999     

Changes in leukocyte count, blood glucose and coagulation system in calves injected with Escherichia coli endotoxin

Responses of leukocyte, blood glucose and coagulation system in calves were investigated to injection with Escherichia coli endotoxin. Severe leukopenia and hyperglycemia following transient hypoglycemia were noted within 24 hours after injection. In the coagulation system, a definite decrease in platelet count, prolongation of prothrombin time and activated partial thromboplastin time were observed. Fibrinogen, soluble fibrin monomer complex and clotting time, however, varied.     

Influence of physical loading on the content of intestinal microflora endotoxin in blood plasma and immunity indices to endotoxin

The content of endotoxin of Gram-negative bacteria and humoral and granulocytic immunity indices to endotoxin in sportsmen and untrained persons before and after undergoing physical load were studied. The study revealed that prior to physical load the content of intestinal microflora endotoxin in the blood stream of volunteer students increased and the humoral immunity indices to endotoxin decreased. Judging by the content of cortisol in the blood, the state of stress increased after a physical load. In the groups with good adaptation a decreased endotoxin content in the blood stream was noted, especially 24 hours after load. On the contrary, in the groups with dysadaptation the content of endotoxin in blood plasma increased after a load and was accompanied by a decrease in antibody titers and in the reserve of leukocytes capable of binding endotoxin.     

Physiological and chemical indicators for early and late stages of sepsis in conscious rats

Endotoxin shock is a major cause of death in patients with septicemia. Endotoxin induces nitric oxide (NO) production and causes tissue damage. In addition, the release of oxygen free radicals has also been observed in endotoxin shock and was found to be responsible for the occurrence of multiple organ failure. The purpose of the present study was to evaluate suitable indicators for early and late stages of endotoxin shock. The experiments were designed to induce endotoxin shock in conscious rats by means of anEscherichia coli lipopolysaccharide (LPS) injection. Arterial pressure (AP) and heart rate (HR) were continuously monitored for 72 h after LPS administration. The maximal decrease in AP and increase in HR and nitrate/nitrite level occurred at 9–12 h following LPS administration. The white blood cell (WBC) count had decreased at 3 h. Hydroxyl radical (methyl guanidine, MG) decreased rapidly after LPS administration. Plasma levels of blood urea nitrogen (BUN), creatinine (Cr), lactic dehydrogenase (LDH), creatine phosphokinase (CPK), and glutamic oxaloacetic transaminase increased before the rise of amylase. Our results suggest that changes in AP, HR, WBC, free radicals, and chemical substances (BUN, Cr) can possibly serve as approximate indicators for the early stage of endotoxin shock. Severe multiple organ damage may be caused by amylase release in the late stage of endotoxin shock.     

内源性一氧化氮在内毒素引起的肺动脉高压和肺损伤中的作用

本实验观察了家兔静脉内注入内毒素的主要成分脂多糖(LPS)后平均动脉血压(MAP)、肺动脉压(PAP)及入、出肺血NO含量的变化,并观察了静脉内预注入NO生成抑制剂Nω-硝基-L-精氨酸(L-NNA)及诱生型NO生成抑制剂氨基胍(AG)后PAP和肺损伤的变化.结果观察到:家兔LPS注入后,MAP均明显下降,LPS注入后0.5、1、1.5、2h PAP明显增高(P<0.05).LPS注入后PAP的高峰期(1h)入肺血NO含量明显降低,出肺血NO无明显变化.与对照组相比,LPS注入后3h出肺血NO含量和5h入、出肺血NO含量均明显增多.相关分析表明,兔LPS注入前和LPS注入后1h PAP与入肺血NO含量呈明显的负相关,而LPS注入后 3h和5h两者相关不明显.静脉预注入L-NNA后,LPS处理组的动物PAP明显增高,入、出肺血丙二醛(MDA)含量也明显增高,动物生存率明显降低.肺组织光镜下可见肺萎陷和小血管淤血加重,白细胞明显增加.静脉预注入AG后,LPS处理组的动物MAP在3～5h明显增高,此时PAP无明显改变,但5h时血中MDA含量明显减低,5h时与LPS组相比肺萎陷和小血管淤血减轻,白细胞也明显减少.以上结果提示,内毒素入血后较早期阶段可出现PAP的升高,此时入肺血NO的减少是参与肺动脉压增高(PAH)的机制之一.家兔内毒素进入血后较早期阶段NO对减轻内毒素引起的PAH和肺损伤起重要作用,而较晚的时期当诱生型NO合酶(iNOS)诱生后释放的NO则参与内毒素引起的肺组织炎症反应和肺损伤.     

Pathogenesis of Lethal Shock After Intravenous Staphylococcal Enterotoxin B in Monkeys

The pathogenesis of shock in the rhesus monkey given intravenous staphylococcal enterotoxin B (SEB) is not understood. Several cardiovascular changes produced by a highly purified preparation of SEB were studied after administration of doses ranging from 50 to 1,000 mug/kg. Irreversible arterial hypotension was found consistently at the higher doses. Arterial blood pressure and cardiac output declined substantially as shock developed. Total peripheral vascular resistance did not rise at any time, but showed a significant fall during the late stages of shock. Portal and central venous pressures remained essentially unchanged. Venous O(2) content and pO(2) declined gradually throughout the period of toxemia, but arterial O(2) content remained constant until just prior to death, when a slight fall was noted in some monkeys. These changes were consistent with a pooling of blood in the peripheral vascular beds and seemed to resemble cardiovascular responses reported to occur in monkeys during shock due to bacterial endotoxin. Epinephrine, administered in the late stages of shock, caused arterial pressure to increase almost immediately and cardiac output to return to normal about 1 min later. Although life could occasionally be prolonged for several hours by continuous or intermittent epinephrine infusions, this therapy never succeeded in reversing the lethal effects of high doses of SEB.     

Changes in the activities of enzymes, especially lactate dehydrogenase, in endotoxin-poisoned mice.

Carbohydrate metabolic disorders were investigated by means of enzyme activities in mice (ddYS) injected intraperitoneally with endotoxin from Salmonella typhimurium. The mice exhibited hyperglycemia 2 hr after administration of endotoxin and hypoglycemia at 18 hr. Activity of hepatic phosphorylase in the endotoxin-poisoned mice at 2 hr was slightly higher than that in the control mice, whereas the level of this activity was not significantly different from that in the controls after 18 hr. Glucose-6-phosphatase activity in the poisoned mice increased by 2 hr after injection, but decreased by 18 hr. The blood lactate level in the poisoned mice transiently decreased until 3 hr after injection, but the mice exhibited a marked lactacidemia by 8–24 hr. The time course of lactate dehydrogenase (LDH) activity in various tissues was examined in mice injected with endotoxin. The activity of hepatic LDH declined to about two-thirds of that of the control mice after 16 hr, and was restored to the normal level by 48 hr. LDH in the cardiac muscle was markedly activated (by about 37%) in the early period (3–6 hr) after administration of endotoxin, and this activity gradually declined. However, the activity of LDH in the skeletal muscle showed a tendency similar to the rise and fall of the levels of blood lactate, and was restored to the normal value at 72 hr after injection. On the other hand, the serum LDH activity in the poisoned mice increased about 1.75-fold by 16 hr after injection. Mice injected with endotoxin exhibited a leakage of the isozymes LDH 3 and 5, but the origin of the leakage is uncertain. Similar elevation in the activities of transaminases (GPT and GOT) and malate dehydrogenase was found in the mouse serum at 16 hr after injection of endotoxin.     

Effect of platelet-activating factor-receptor antagonism on endotoxin-induced lung dysfunction in sheep

To further define the role ofplatelet-activating factor (PAF) in endotoxin-induced lung dysfunction,we examined the effect of ABT-299, a specific and potent PAF-receptorantagonist, on the response to endotoxemia in six chronicallyinstrumented awake sheep. We administered Escherichiacoli endotoxin (0.5 µg/kg) intravenously with orwithout pretreatment with ABT-299 while monitoring mean pulmonaryarterial pressure (Ppa), mean systemic arterial pressure (Psa), dynamiccompliance of the lungs (Cdyn), and functional residual capacity (FRC).Endotoxin administration caused pulmonary hypertension, reduced Cdyn,leukopenia, and hypoxemia while having no significant effect on Psa orFRC. Administration of ABT-299 did not affect any of the measuredvariables at baseline. Pretreatment with ABT-299 attenuated the peakPpa seen after endotoxin administration but had minimal effects onendotoxin-induced changes in Cdyn, white blood cell count, oralveolar-to-arterial oxygen difference. ABT-299 was shown to completelyblock the pulmonary hypertension and reduction in Cdyn seen afterintravenous administration of exogenous PAF. We conclude that PAF doesnot play an essential role in the sheep's response to endotoxin.

     

Adenine induced granulocytosis in the rabbit.

Peripheral blood specimens from rabbits injected parenterally with physiological saline, adenine sulfate and guanine sulfate were examined for white blood cell count changes. A significant leukocytosis occurred within forty-eight hours only after adenine sulfate administration. A differential analysis revealed the increase was in the heterophil (pseudoeosinophil, amphophil) population. A mild lymphopenia was noted. There were no clear cut trends in the eosinophil, basophil and monocyte populations. No leukocyte morphological changes were found on peripheral blood smears.     

内毒素在大剂量顺铂所致大鼠急性肾损伤过程中的变化及意义

目的利用大剂量顺铂（cisplatin,DDP）所致大鼠急性肾功能衰竭的动物模型,观察外周血内毒素（endotoxin）在大鼠急性肾损伤中的变化及其意义。方法SD大鼠36只,雌雄各半,依体重随机分为DDP用药6h、48h、对照组和生理盐水（NS）用药6h、48h、对照组,每组6只。10mg／kgDDP单次腹腔内注射,等量Ns对照。观察并记录用药后对照组大鼠的毒副反应;用药6、48h各组大鼠无菌条件下心脏穿刺取血、肝素抗凝,检测外周血内毒素含量,同时内眦静脉取血,测定血清尿素氮、肌酐浓度,并进行统计学分析。结果DDP用药后6h,大鼠体重开始明显降低,用药48h后,大鼠腹泻逐渐加重,用药3d后大鼠死亡。DDP用药后6h大鼠血尿素氮、肌酐的含量与对照组比较差异无显著性（P〉0．05）;DDP用药后48h血尿素氮升至（18．71±9．9）mmol／L,明显高于对照组（7．48±0．6）mmol／L（P〈0．05）,同时血肌酐含量亦升至（49．6±14．1）μmol／L,与对照组（27．17±1．7）μmol／L比较差异具有显著性（P〈0．05）。DDP用药后6h所有大鼠外周血内毒素含量都低于0．0218Eu／rrd最低检出限,明显低于NS对照组大鼠（0．3141±0．1477）Eu／ml（P〈0．01）;DDP用药后48h大鼠外周血内毒素的含量增高均超过0．70Eu／ml最高检出限,明显高于NS对照组大鼠（0．1661±0．1198）Eu／ml（P〈0．01）。结论外周血内毒素含量的变化与大剂量顺铂所致大鼠急性肾损伤早期的发病机制无关,但与大鼠肾功能衰竭有关的发生相关。     

Partial recovery of neutrophil functions during prolonged hypothermia in pigs

The changes in circulation and migration of mature and immature neutrophils during 12 h of hypothermia have been studied using an experimental pig model. At 29 degrees C the number of circulating neutrophils fell from 5 +/- 1.1 at 37 degrees C to 3.5 +/- 0.6 X 10(9)/l and then remained unchanged while hypothermia was maintained. The number of circulating immature neutrophils did not fall during hypothermia. During hypothermia, hydrocortisone failed to stimulate the release of mature and immature neutrophils from the bone marrow. In contrast, endotoxin caused a profound neutropenia followed by a gradual increase in the number of circulating mature neutrophils, which by 6 h, was similar to the number circulating before endotoxin administration. At 29 degrees C the number of circulating immature neutrophils also fell following endotoxin but then increased over the number circulating before endotoxin administration by approximately 10-fold. Compared with neutrophil migration at 37 degrees C, very few mature or immature neutrophils migrated to an inflammatory site during the 12 h of hypothermia (29 degrees C). Unlike hypothermia in vitro, where neutrophil function may improve with time in vivo, neutrophil function remains compromised.     

内毒素和细胞因子在腹部火器伤肠管穿透后血液中的变化及意义

目的：探讨内毒素和细胞因子在腹部火器伤肠管穿透后血液中的变化规律及意义。方法：健康长白仔猪42头随机等分为对照组和伤后1h、2h、4h、8h、12h和24h组,实验组建立腹部火器伤肠管穿透模型后,用显色基质鲎试剂法检测各组血浆内毒素水平,采用双抗体夹心ELISA法测定各组动物血清TNF-α、IL-6水平,并观察各个时间点的体温变化。结果：实验各组的血浆内毒素水平及血清TNF-α、IL-6水平均明显高于对照组（P〈0.05）,血浆内毒素于伤后8h达到高峰,伤后12h仍维持在高峰值水平（P〈0.05）;血清TNF-α在伤后12h为（94.36±10.18）ng/L,IL-6在伤后12h为（1218.35±74.00）ng/L,二者均于伤后12h达到高峰并与伤后血浆内毒素水平变化一致。伤后动物体温逐渐升高,在伤后12h、24h实验组的平均体温达40℃以上。结论：腹部火器伤肠穿孔后内毒素血症可能诱导了血液中TNF-α、IL-6的产生,并参与了腹部肠管火器伤后机体的病理生理过程。     

Nutritional state and endotoxin fever of newborn rabbits.

At thermoneutral environments 6-10 day-old well-fed rabbits responded to 20 microgram/kg I.V. E. coli endotoxin with biphasic fever: temperature peaks at 60 and 120-150, and a transient fall between 60 and 90 min after endotoxin injection. In rabbits starved for 24 hours, and in runt rabbits body temperature did not rise, but a decline started 60 min after endotoxin administration, corresponding to the transient fall observed in well-fed animals and continuing until about the 100-120th min; thereafter body temperature tended to stabilize at the low level.     

Age-related differences in the effect of glucagon on metabolism in rat liver.

The authors found differences in the metabolic response of 10- and 120-day-old rats to glucagon. In 10-day-old young, the administration of glucagon was followed in 5 min by an abrupt small increase in the blood sugar level, which continued to rise and attained the maximum 2 hours after the injection of glucagon. In adult rats there was an abrupt large increase in the blood sugar level in the first minutes after administering glucagon; after that the blood sugar level fell, but remained significantly higher than in the controls. In a series of experiments on the isolated perfused liver, no differences were found in glucose and protein release from the liver into the perfusion medium, but the protein concentration in the liver of the younger rats fell. The results show that the liver of young rats, after the injection of glucagon, draws on its own protein resources for the substrates needed for gluconeogenesis.