Effect and mechanism of Qing-Kai-Ling on endotoxin-induced fever in rabbits

AIM:To explore the antipyretic mechanism of Qing Kai-Ling (QKL) injection on endotoxin (ET)-induced fever in rabbits.METHODS:Rabbit models of endotoxin (ET)-induced fever were duplicated. The rectal temperature was measured by digital thermograph. The cAMP and IL-1β content in the hypothalamus (HP), the cAMP content in the cerebrospinal fluid (CSF), and the arginine vasopressin (AVP) content in the ventral septal area (VSA) were determined by radioimmunoassay.RESULTS:① QKL had significant antipyretic effect on ET-induced fever(P<0.01), ② The production of IL-1β and cAMP in HP was significantly inhibited by QKL treatment (P<0.01), ③ QKL markedly decreased the cAMP content in the CSF and AVP content in the VSA(P<0.01).CONCLUSION:The antipyretic mechanisms of QKL are probably due to inhibiting the production of the endogenous pyrogen and central mediator of fever, and meanwhile stimulating the release of the antipyretic substances.     

Effect of endotoxin on phospholipids of hepatic mitochondria membrane and cation A antagonism in rabbits

AIM: To investigate the effect of endotoxin on phospholipid of hepatic mitochondria membrane (MiM) and cation A (CA) antagonism in the model of endotoxemia in rabbits. METHODS: Forty-eight healthy Japanese big-ear rabbits were randomly divided into 3 groups: the normal control (groupⅠ), endotoxin treatment group (groupⅡ) and cation A and endotoxin treatment group (group Ⅲ). The contents of phosphatidylcholine (PC), phosphatidylethanolamin (PE), phosphatidylserine (PS) and phosphatidylinositol (PI) in MiM of three groups were measured at the 3rd or 7th hour after corresponding treatment. RESULTS: The contents of the four phospholipids in groupⅡ were lower than those in groupⅠ during the experiment (P<0.01). A significant increase in the contents of four phospholipids in group Ⅲ was observed as compared to group Ⅱ (P<0.05, P<0.01). CONCLUSION: Endotoxin decreases the major membrane phospholipids in MiM, whereas CA has a prominent protective effect on injuries by endotoxin in MiM and provides a valuable evidence for the use of some drugs of endotoxin antagonist.     

Effect of Qing-Kai-Ling Injecta on cAMP content of hypothalamus and AVP content in ventral septal area of endotoxin-induced febrile rabbits

AIM:To investigate the mechanism of Qing-Kai-Ling(QKL) Injecta suppressing endotoxin(ET)-induced fever in rabbits.METHODS:①The ET-induced fever model was established in rabbits. QKL injecta was administered intravenously, and the febrile response of rabbits was observed. The cAMP content in the hypothalamus (HP) and arginine vasopressin (AVP) content in the ventral septal area (VSA) were determined by radioimmunoassay.RESULTS:①The maximal increment in body temperature (△T) ,6 h thermal response index (TRI₆)(29.59±10.39), cAMP content in the HP and AVP content in the VSA in the ET group were significantly higher than those in the normal saline (NS) group and the QKL+ET group .②The positive correlation was observed between the cAMP content in the HP and the fluctuation of body temperature (r=0.904,P＜0.01).CONCLUSION:The antipyretic mechanisms of QKL were probably due to inhibiting the increase in cAMP content in HP, and meanwhile stimulating the release of AVP in VSA.     

Effect of Nao-re-qing oral liquid on cAMP content in hypothalamus and CSF,and AVP content in ventral septal area of endotoxin-induced febrile rabbits

AIM: To explore the mechanism of Nao-re-qing oral liquid (NRQ) decreasing endotoxin (ET)-induced fever in rabbits. METHODS: (1) The ET-induced fever model was established in rabbits. Febrile response of rabbits was observed. (2) The arginine vasopressin (AVP) content in the ventral septal area (VSA), and cAMP content in hypothalarmus (HP) and CSF were determined by radioimmunoassay.RESULTS: (1) In ET group, the maximal increment in body temperature (ΔT) [(1.80±0.16) ℃], 6 h thermal respone index (TRI₆)(11.31±0.20), the cAMP content in the HP [(1.35±0.21)nmol/g], the cAMP content in CSF [(66.69±1.82) nmol/L] and AVP content in the VSA [(30.80±9.59)ng/g ] were significantly higher than those in NRQ+ET group[ΔT(0.82±0.08) ℃, TRI₆(5.73±0.09), HP: cAMP(0.70±0.50)nmol/g, CSF: cAMP(56.86±1.34), AVP:(11.91±3.47)ng/g]( P<0.01). (2) The AVP content in VSA, and cAMP content in HP and CSF were separately paralleled with the fluctuation of body temperature (AVP: r=0.972, P<0.01; HP: cAMP r=0.899, P<0.05; CSF: cAMP r=0.991, P<0.01). CONCLUSION: The antipyretic action of NRQ may be due to inhibiting the increase in cAMP in HP and meanwhile promoting the release of AVP in VSA.     

Effect of Jiere Xingshen Injection on cAMP,IL-1β content in hypothalamus of ET febrile rabbits

AIM: The effects of Jiere Xingshen(JRXS) Injection on cAMP, IL-1_β content in hypothalamus (HP) of endotoxin(ET)-induced feverish rabbits were studied. METHODS: The ET-induced fever model was established in rabbits and the cAMP content in hypothalamus (HP) and csf, IL-1_β content in HP were determined by radioimmunoassay following intravenous infusion of JRXS. RESULTS: In ET group, the ΔT[(0.40±0.11)℃], TRI₁(1.78±0.79), cAMP content in HP[(2.90±0.40)nmol/g], cAMP content in csf[(0.40±0.11)nmol/L)], IL-1_β content in HP[(6.08±0.79)ng/g] were higher than that of NS and JRXS+ET group (P＜0.01). In JRXS+ET group, the ΔT[(0.10±0.10)℃], TRI₁(0.36±0.64), cAMP content in HP[(1.37±0.27)nmol/g], cAMP content in csf[(14.4±3.69)nmol/L)], IL-1_β content in HP[(2.90±0.37)ng/g] were very close to that of NS group but lower than that of the ET group (P＜0.01);The cAMP content in HP and csf, IL-1_β content in HP paralleled with the fluctuation of temperature. CONCLUTION: JRXS Injection has significant inhibitory effect on ET-induced fever by inhibiting cAMP and IL-1_β production in hypothalamus.     

Effect of Naoreqing on endotoxin-induced fever in rabbits

AIM:To observe the antipyretic effect of Naoreqing (NRQ) oral solution in rabbits with endotoxin-induced fever.METHODS:The ET-induced fever model was established in rabbits.The digital thermometer was used to register rectal temperature.The endothelin content in blood plasma,and tumor necrosis factor-α (TNFα) in blood serum were determined by radioimmunoassay.The activities of tissue-type plasminogen activator (t-PA) and plasminogen activator inhibitor (PAI) in plasma were measured by the assay of chromogenic substrate.At the same time，the pathology of lung,kidney and liver were observed.RESULTS:① NRQ showed obvious antipyretic effect in the rabbits with endotoxin-induced fever (P<0.01).② NRQ inhibited the endothelin content in plasma and TNFα content in serum,and at the same time reduced activity of PAI (P<0.01) and improved activity of t-PA in plasma (P<0.01).③ NRQ reduced the pathology of congestion of lungs,liver and renal in febrile rabbits.CONCLUSION:NRQ has an antipyretic effect .The mechanism is maybe related to its adjusting the balance of coagulant substance and anticoagulant substance,and at the same time inhibiting the secretion of TNFα in febrilic rabbits.     

Signal transduction in cells induced by endotoxin

Depending on LBP/CD14 systems, LPS activates a series of signal-transducing systems in cells. Protein tyrosin kinase (PTK) system, ceramide activated kinase (CAK) system might play an important role in cells signal-transducing. This article give a summary about signal transduction in cells induced by endotoxin.     

Effect of patchouli oil on lipopolysaccharide-induced fever in rabbits

AIM:To investigate the antipyretic effect of patchouli oil on lipopolysaccharide (LPS)-induced fever in rabbits. METHODS:Male rabbits (n=42) were randomly divided into 7 groups according to their body weight and basal body temperature, including control group, model group, western medical positive group, traditional Chinese medical positive group, and high, middle and low doses (2%, 1% and 0.5%) of patchouli oil groups. Subsequently, except the controls, the rabbits were injected with LPS at a dose of 1 mL/kg (2 mg/L) through marginal ear vein to establish rabbit fever model and the rabbits in control group received the same volume of NS. The rabbits in control group and model group were injected with 0.5% Tween-80 0.5 h late, and the rabbits in the other groups were treated with correspoonding drugs. The effect of patchouli oil on the body temperature was observed, and the levels of interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) in the serum, and prostaglandin E2 (PGE2) and cyclic adenosine monophosphate (cAMP) in the hypothalamus were measured by radioimmunoassay. RESULTS:The body temperature and the levels of IL-1β, TNF-α, cAMP and PGE2 in model group were significant higher than those in control group. Patchouli oil notably inhibited the body temperature in the febrile rabbits. From 1.5 h to 5.5 h after administration, the body temperatures were increased by (1.06±1.55), (1.62±1.36), (1.38±1.22), (0.98±0.98) and (0.48±0.95) ℃ in high patchouli oil group, respectively. From 3.5 to 5.5 h after administration, the body temperatures were elevated by (1.47±0.73), (1.15±0.68) and (0.63±0.54) ℃ in middle patchouli oil group, respectively. A tendency of downregulation of the elevated body temperatures was observed at every time point after administration in low patchouli oil group. Patchouli oil significantly decreased the levels of TNF-α in the serum and cAMP content in the hypothalamus, and attenuated the elevated tendency of the IL-1β level in the serum and PGE2 level in the hypothalamus.CONCLUSION: Patchouli oil evidently has antipyretic effect on LPS-induced fever in the rabbits. The antipyretic mechanism might be related to the inhibition of TNF-α level in serum and cAMP content in the hypothalamus.     

Effects of aminoguanidine on endotoxin-induced acute lung injury in rabbits

AIM: To observe the effect of aminoguanidine (AG) on hemodynamics and lung capillary permeability in acute lung injury (ALI) in rabbits. METHODS:24 rabbits were equally divided into four groups: saline group, endotoxin group, AG group and AG plus endotoxin group. In AG plus endotoxin group, endotoxin was injected to animals to make an ALI model, 25mg/kg AG was injected following that and let this sustain 3 hours. Meanwhile, mean arterial pressure (MAP), mean pulmonary arterial pressures (MPAP) and blood gas analyses were observed during this period. At the end of the experiment, broncho-alveolus lavage was performed, pathologic samples were treated routinely and lung wet weight/dry weight ratio was calculated. RESULTS:After endotoxin injection, MAP and arterial oxygen pressure (PaO₂) decreased, and MPAP increased significantly. The injection of AG had little effect on MAP, but AG could markedly decrease MPAP and increase PaO₂. Cell count in broncho-alveolus lavage fluid (BALF) was less in AG plus endotoxin group than in endotoxin group. Although AG did not affect total protein in BALF, low molecular weight proteins decreased in AG plus endotoxin group by the assay of electrophoresis. Tissue wet weight/dry weight ratio also decreased in this group. Pathologic study showed that there were fewer inflammatory cells and less lung edema in AG plus endotoxin group. CONCLUSION:AG could improve hemodynamics status and attenuate acute lung injury induced by endotoxin in rabbits.     

Effects of glycine/polymyxine B mixture on endotoxin-induced acute phase response in rabbits

AIM: To explore effects of glycine and polymyxin B mixture (Gly/PMB) on endotoxin-induced acute phase responsein vivo. METHODS: Model of acute phase response was reconstructed by endotoxin (ET) in rabbits. Specimens of blood were collected at 1 hour after the highest body temperature. Leukocyte count, serum C-reactive protein and trace element were also detected. RESULTS: Pretreatment of half-dose Gly/PMB significantly inhibited acute phase response induced by ET (P＜0.05) in vivo, and serum C-reaction protein and trace element tended to normal level. There was no significant difference in inhibitory effects on ET-induced acute phase response between half-dose of Gly/PMB and total-dose of PMB (P＞0.05). CONCLUSION: These results suggested that glycine enhanced the inhibitory effect of polymyxin B on ET-induced acute phase response. The advantage of glycine and polymyxin B mixture was decreasing dosage and side effects of polymyxin B.     

Synergetic antagonism of polymyxin B associated with glycine to pyrogenous effect of endotoxin

AIM and METHODS: To investigate the antagonistic effects of polymyxin B(PMB) in combination with glycine(Gly) on the pyrogenicity of endotoxin(ET) in rabbits and the LD₅₀ of PMB in mice. RESULTS: (1)The antagonistic effect of PMB plus Gly was augmented and the optimal combination was PMB(30000 U) plus Gly(15 mg) to ET(0.01 μg); (2)The LD₅₀ of PMB with or without Gly were 8.38×10⁴U/kg and 6.06×10⁴ U/kg in mice, respectively. CONCLUSION: The antagonistic effect of PMB plus Gly on ET showed synergnism and this combination could decrease the toxicity of PMB.     

Influence of SDD and caecostomy/colonic irrigation on gut endotoxin/bacteria translocation following acute severe pancreatitis

AIM: To observe the influence of the selective decontamination of the digestive tract (SDD) and caecosomy/colonic irrigation on gut endotoxin/bacteria translocation following acute severe pancreatitis (ASP). METHODS: Twenty three pigs weighing 16-22 kg were divided into four groups. Group I (n=5): sham-control; Group Ⅱ (n=6): ASP-control; Group Ⅲ (n=6): gntamicin [(8.55×10⁵±5.70×10⁴)units/time] and nystatin [(1.37×10⁵±9.00×10³)units/time]were fed orally every 8 h for 1 week before the induction of ASP; Group Ⅳ (n=6): caecostomy was performed before the induction of ASP. ASP was induced by infecting 1 mL/kg BW of combined solution of 5% sodium taurocholate and (8-10)×10⁶ BAEE units/L of trypsin into pancreas via pancreatic duct. Systemic plasma endotoxin levels were quantified by the chromogenic limulus amebocyte lysate (LAL) technique. Specimens of tissue from mesenteriolum and mesocolon lymph nodes, lung, lymph nodes in hilus pulmonis, pancreas and the samples of both portal and systemic blood were collected before and at 72 h following ASP and cultured for aerobic as well as anaerobic bacteria growth. Positive specimens were subcultured and the bacteria identified by standard procedure. RESULTS: Preventive SDD not only effectively reduced the amount of bacteria in stool (P<0.01), but also significantly reduced the levels of plasma endotoxin and the magnitude of bacteria translocation to the portal and systemic blood and the remote organs and tissues, for instance, mesenteriolum and mesocolon lymph nodes, lung, lymph nodes in hilus pulmonis, pancreas. Early caecostomy/colonic irrigation also significantly reduced the levels of translocated origin-endotoxin and bacteria after ASP. CONCLUSIONS: SDD and caecostomy/colonic irrigation effectively reduce the levels of plasma endotoxin and the magnitude of bacteria translocation to the portal and systemic blood and the remote organ, especially the latter will be of a great importance in the future clinical practice.     

Effects of endotoxin on phospholipid metabolism and membrane fluidity in liver mitochondria of goats

AIM and METHOD:To study the changes of contents of phosphatidyl inositol (PtdIns), phosphatidylserine (Ptdser), phosphatidylethanolamine (PtdEtn) and phosphatidylcholine(PtdCho) in hepatic mitochondria membrane of goats in vivo at 5 h after administration of E. coli endotoxin(1800 U/kg body weight) with HPLC. The membrane fluidity of the erythrocyte and liver mitochondria of E. coli endotoxin treated group was examined with the fluorescence polarization technique, in which 1, 6-diphenyl-1, 3, 5, -hexatriene was used as a fluorescence probe. RESULTS:E. coli endotoxin treated group (group II) led to a marked decrease of PtdIns, PtdSer, PtdEtn, PtdCho contents of hepatic mitochondria in vivo at 5 h as compare to the normal control (group I) (P＜0.01). The fluorescence anisotropy (A) parameters of erythrocytic and liver mitochondria membrane in group II were higher than those in group I(P＜0.01). CONCLUSION: E. coli endotoxin could induced marked decrease of membrane phospholipid contents and membrane fluidity.     

Progress in studying the mechanism of fever using knockout mice

Increasing evidence suggests that a complex net-work of fever induction pathways in mammalian exists. In this article, the overview of recent studies on the mechanism of fever induced by different pyrogens using IL-1, IL-1R, ICE, IL-1ra, IL-1RacP, IL-6, IL-10, TNFR, cPLA₂, COX, EP, AT₂, iNOS and D_2/3 knockout mice is presented. Hyperthermia respond to localized infection/inflammation (e.g., sc injection of turpentine) is mediated by IL-1β and IL-6 in turn.While fever induced by systemic infection/inflammation (e.g., treatment with LPS intraperitoneally) varies with the different doses of pyrogens administered. Fever caused by a low dose of LPS administered ip is IL-6 dependent, but the IL-6 independent pathway is crucial for the fever evoked by a high dose of LPS. Febrile responses during both local and systemic infection/inflammation develop totally through central PGE₂ dependent mechanism, but some stress induced hyperthermia otherwise.     

Intracellular calcium alterations induced by endotoxin and IL-1β in rabbit hypothalamic neurons

AIM: To investigate intracellular free calcium ( [Ca²⁺]i ) alterations in hypothalamus of febrile rabbits induced by endotoxin (ET), and compare with the effect of ET and IL-1β on i in hypothalamic neurocytes from normothermia rabbits. METHOD: The concentration of [Ca²⁺]i was determined by using spectrofluorometer and fluorescent Ca²⁺ probe fura-2 /Am. RESULTS: 1. A minute dose of ET (2 ng/mL) induced a significant rise in [Ca²⁺]i in hypothalamic neurocytes from normothermia rabbits. The rise in [Ca²⁺]i in hypothalamic neurocytes from febrile rabbits induced by intravenous injection of ET was also observed. 2. In hypothalamic neurocytes from normotheria rabbits, IL-1β failed to affect [Ca²⁺]i at concentrations of 100, 500, 1 000ng/mL, respectively. CONCLUSION:The action site of low concentration of calcium that plays a regulatory role during fever seems unlikely to be in cytosolic compartment of hypothalamic neurons. The change of [Ca²⁺]i in hypothalamic neurocytes by ET can not be considered the direct effect of IL-1β.     

Effect of glycine on lipopolysaccharide and hypoxia-induced necrotizing enterocolitis in rats

AIM:To investigate the effect of glycine on endotoxin and hypoxia-induced necrotizing exterocolitos (NEC) in rats. METHODS:In glycine+NEC group, twenty anesthetized and artificially ventilated rats received 1g/kg glycine (20%, iv). Five minutes later, the rats were treated with 2 mg/kg lipopolysaccharide (LPS). In control group (NS+NEC), twenty rats were treated with normal saline as a substitute for glycine. In all animals, FiO₂ was reduced after 90 min from 21% to 5% and ventilation continued until 180 min or death. At the end of the experiment, the samples of blood and intestine were obtained immediately. Serum TNFα was measured with ELISA, serum NO was determined by nitrate reductase. The histopathology of the necrotic lesions were categoried: grade Ⅰ, focal mild injury confined to villous tips; grade Ⅱ, partial loss of villi; grade Ⅲ, necrosis extending to submucosa; grade Ⅳ, transmural necrosis. RESULTS:The survival time was shorter in the NS+NEC group (P＜0.01). The intestinal injury of the rats in glycine+NEC group was markedly alleviated (P＜0.01). The levels of TNF-α and NO₂^-/NO₃^- in serum decreased significantly in animals treated with glycine (P＜0.01, P＜0.05). CONCLUSION:Glycine alleviated LPS-induced NEC by inhibiting excessive production of TNFα and nitric oxide.     

Effect of intestinal endotoxemia on hepatic energy metabolism in acute liver failure

AIM:To study the effect of intestinal endotoxemia(IETM) on hepatic energy metabolism in acute liver failure. METHODS:Intoxication by thioacetamide (TAA) was used to establish rat model of acute liver injury.Ketone body(acetoacetate and β-hydroxybutyrate) in arterial blood and ATP content of hepatocellular mitochondria were determined by using enzymatic fluorimetric micromethod.Colectomy was adopted in observing the changes in plasma endotoxin content and serum alanine aminotransferase (ALT) activity. RESULTS:In the TAA group,plasma endotoxin content and serum ALT activity were all significantly higher than those in the control group(P＜0.01),arterial ketone body ratio of acetoacetate to β-hydroxybutyrate (AKBR) decreased below 0.4,total ketone body in arterial blood was significantly lower than that in the control group(P＜0.01).In the TAA+colectomy group,there was no endotoxemia to be found,ATP content of hepatocellular mitochondria was significantly higher than that in the TAA group(P＜0.01), though serum ALT activity was higher than that in the control group(P＜0.05),but significantly lower than that in the TAA group(P＜0.01). CONCLUSION:IETM played a key role in the occurrence of acute liver failure,hepatic dysfunction might be caused by IETM through damaging hepatic energy metabolism.     

Effect of pulmonary vascular endothelial cells on the development of acute lung injury in rats

AIM: Effect of endothelial cell on the development of acute lung injury and the prevention of dexamethasone in acute lung injury were observed.METHODS:Rats were divided into three groups:1.Control group.2.LPS group:Venous injection with LPS(5mg/kg body weight),execute respectively at 1 h,2 h,6 h and 24 h after LPS injection. 3.dexamethasone group:intraperitoneal injection with dexamethasone ,1 h before LPS injection,execute after 2 hours after LPS injection.RESULTS: Serum NO,TNF-α levels,lung iNOS activity and lung ICAM-1mRNA expression were increased( P <0.05, P <0.01, vs control group),but serum ACE was decreased( P <0.01).Dexamethasone could improve all the changes above mentioned.CONCLUSION:Endothelial cell played a vital role in the development of acute lung injury and dexamethasone could prevent acute lung injury.