[The Role of Hydrogen Sulfide in Acute Liver Injury Induced by Traumatic Stress in Rats].

OBJECTIVE: To explore the role of hydrogen sulfide (H2S) in acute liver injury induced by crushing hind limbs of rats. METHODS: The rats were randomly divided into the following groups: control, crushing, H2S donor sodium hydrosulfide (NaHS) + crushing, H2S inhibitor propargylglycine (PAG) + crushing group. The acute liver injury model was established by 'crushing the hind limbs of rats with standard weight. Rats were sacrificed at 30 min and 120 min after the crush. The activities of serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were measured by colorimetric method, and the content of H2S in plasma and the contents of malondialdehyde (MDA), protein carbonyl, glutathione (GSH) in the liver and the activity of H2S generating enzyme (cystathionine y-lyase, CSE) were determined by chemical method. The expression of CSE mRNA in liver was detected by RT-PCR. RESULTS: For crush injury group, the levels of AST and ALT in serum, MDA and protein carbonyl in liver increased. The levels of GSH, CSE, CSE mRNA in liver and H2S in serum decreased. The administration of NaHS before limbs crush could attenuate the changes of liver injury, but the pre-treatment with PAG could exacerbate the changes. CONCLUSION: The decrease of H2S production could involve in mediating the acute liver injury induced by traumatic stress in rats.

[Effects of HO-1 on Lipopolysaccharide-induced Endoplasmic Reticulum Stress of Rat Hepatocytes].

OBJECTIVE: To investigate effects of antioxidant stress protein heme oxygenase-1 (HO-1) on lipopolysaccharide (LPS)-induced endoplasmic reticulum stress (ERS) of rat hepatocytes. METHODS: The BRL cells (rat hepatocyte cell line) were cultured. The hepatocytes were treated with LPS, LPS+HO-1 siRNA, HO-1 siRNA and PBS solution, respectively. The cell viability was measured by trypan blue exclusion test. The apoptosis cells were detected by the fluorescent dye Hoechst 33258. Expressions of GRP78, CHOP, caspase-12 and HO-1 were detected by Western blotting. RESULTS: LPS caused an increase of HO-1 protein expression of rat hepatocytes in a dose-dependent and time-dependent manner, a up-regulation of GRP78, CHOP and caspase-12, a decrease in cell viability, and an increase in apoptosis rate of hepatocytes. Pretreatment of HO-1 siRNA inhibited the up-regulation of LPS-induced HO-1, however, aggravated ERS and cellular injury. CONCLUSION: HO-1 inhibites ERS-mediated cellular injury of rat hepatocytes induced by LPS.

[Nitric oxide mediated TNF-α, IL-1ß gene expression in liver induced by crush injury of rat's soft tissues].

OBJECTIVE: To explore the effect of nitric oxide (NO) on the gene expression of hepatic TNF-α and IL-1ß by crush injury of rat's soft tissues. METHODS: Rats were randomly divided into sham group, crush group, crush+aminoguanidine (AG) group, and crush+L-arginine (L-Arg) group. Activities of ALT and AST as well as NO level in serum were measured. Gene expressions of TNF-α and IL-1ß were detected with RT-PCR. RESULTS: Obvious increase in TNF-α and IL-1ß mRNA expression was detected in the crush group compared with the sham group (P<0.05). After pretreated L-Arg, expressions of TNF-α and IL-1ß mRNA were markedly increased (P<0.05). After pretreated AG, those indices obviously decreased (P<0.05). Activities of ALT and AST enhanced and NO level increased in the crush group compared with the sham group (P<0.05). Pretreatment with L-Arg or AG led to substantial increased or reduced activities of ALT and AST as well as NO levels, respectively. CONCLUSION: Endogenous NO mediated TNF-α, IL-1ß mRNA up expression in liver induced by increased production of NO after crush injury of rat's soft tissues.

Negative modulation of NO for diaphragmatic contractile reduction induced by sepsis and restraint position.

In practice of forensic medicine, potential disease can be associated with fatal asphyxia in restraint position. Research has demonstrated that nitric oxide (NO) and nitric oxide synthase (NOS) are plentifully distributed in skeletal muscle, contributing to the regulation of contractile and relaxation. In the current study, respiratory functions, indices of diaphragmatic biomechanical functions ex vivo, as well as NO levels in serum, the expressions of diaphragmatic inducible NOS (iNOS) mRNA, and the effects of L-NNA on contractility of the diaphragm were observed in sepsis induced by cecal ligation and puncture (CLP) under the condition of restraint position. The results showed that in the CLP12-18h rats, respiratory dysfunctions; indices of diaphragmatic biomechanical functions (Pt, +dT/dt(max), -dT/dt(max), CT, Po, force over the full range of the force-frequency relationship and fatigue resistance) declined progressively; the NO level in serum, and iNOS mRNA expression in the diaphragm increased progressively; force increased significantly at all stimulation frequencies after L-NNA pre-incubation. Restraint position 1 h in CLP12 h rats resulted in severe respiratory dysfunctions after relative stable respiratory functions, almost all the indices of diaphragmatic biomechanical functions declined further, whereas little change took place in NO level in serum and diaphragmatic iNOS mRNA expression; and the effects of L-NNA were lack of statistical significance compared with those of CLP12 h, but differed from CLP18 h group. These results suggest that restraint position and sepsis act together in a synergistic manner to aggravate the great reduction of diaphragmatic contractility via, at least in part, the negative modulation of NO, which may contribute to the pathogenesis of positional asphyxia.

[Expression of CaMK II delta in cerebral cortex following traumatic brain injury].

OBJECTIVE: To observe the time-course expression of calcium-calmodulin dependent protein kinase II delta (CaMK II delta) in cerebral cortex after traumatic brain injury (TBI). METHODS: The TBI rat model was established. The expression of CaMK II delta in cerebral cortex around injured area was tested by Western blotting and immunohistochemical staining. RESULTS: Western blotting revealed expression of CaMK II delta in normal rat brain cortex. It gradually increased after TBI, peaked after 3 days, and then returned to normal level. The result of immunohistochemical staining was consistent with that of Western blotting. CONCLUSION: The expression of CaMK II delta around injured area after TBI increased initially and then decreased. It could be used as a new indicator for wound age determination following TBI.

[Endoplasmic reticulum stress mediates lipopolysaccharide-induced apoptosis in rat hepatocyte].

OBJECTIVE: To investigate the role of endoplasmic reticulum stress (ERS) in lipopolysaccharide (LPS)-induced hepatocyte apoptosis. METHODS: Cells of the rat hepatocyte line BRL were cultured. The hepatocytes were treated with LPS, ERS inducer thapsigargin (TG), and ERS inhibitor 4-phenylbutyric acid (4-PBA), respectively or in their different combination. The cell viability was measured by MTT assay. The cyto-nuclear morphological changes of apoptosis cells were detected by the fluorescent dye Hoechst 33258. The apoptosis rate was assessed by flow cytometry with Annexin V-FITC/PI double-staining. Expressions of GRP78 as ERS marker protein, CHOP, caspase-12 and cleaved-caspase-3 as ERS related protein were detected by Western blotting. RESULTS: LPS could cause a decrease in cell viability and an increase in apoptosis rate in a dose- and time-dependent manner. The expression of GRP78, CHOP, caspase-12 and cleaved-caspase-3 proteins were significantly increased with LPS treatment. TG led to a marked decrease in cell viability and an increase in apoptosis rate, which aggravated the hepatocyte injury induced by LPS; whereas 4-PBA alleviated LPS-induced apoptosis. CONCLUSION: ERS mediates LPS-induced hepatocyte injuries, indicating that ERS may play a vital role in the pathogenesis of LPS-induced hepatocyte injuries.

[Changes of MDA, SOD, TNF-alpha, and IL-1beta in rat brain tissue after concussion].

OBJECTIVE: To observe the changes of malondialdehyde (MDA), superoxide dismutase (SOD), tumor necrosis factor-alpha (TNF-alpha), and interleukin-1beta (IL-1beta) in rat brain tissue and to explore the mechanism of secondary cerebral injury after brain concussion. METHODS: The brain concussion model was established with the pathological changes of rat brain tissue by Weil stain. The expressions of MDA and SOD in brain tissue were examined by photochemical method. The expressions of TNF-alpha and IL-1beta in cerebral cortex and hippocampus were examined by immunochemistry. RESULTS: Nerve myelin sheath showed disorder, disruption, gryposis and swelling by Weil stain. Above changes were more severe at 12h. The quantity of MDA in rat brain tissue after concussion was significantly higher than that in the control group. The activity of SOD was significantly lower than that in the control group. The expressions of TNF-alpha and IL-1beta increased more significantly in cerebral cortex and hippocampus in rat brain tissue after concussion than that in the control group. CONCLUSION: Oxidative stress and inflammatory injury in the rat brain tissue, which may play an important role in secondary cerebral injury after concussion.

[Myocardial expression of Spry1 and MAPK proteins of viral myocarditis].

OBJECTIVE: To discuss the myocardial expression of Spry1 and MAPK proteins of viral myocarditis (VMC), to reveal its mechanism of sudden death, and to provide guides for forensic identification of sudden cardiac death. METHODS: Thirty Balb/c male mice were randomly divided into VMC group and control group, inoculated intraperitoneally with Coxsackievirus B3 and Eagel's solution, respectively. After the mice were sacrificed, the cardiac tissues of the mice were taken to proceed regular pathological examination. The changes of Spry1 protein, Spry1 mRNA and MAPK protein were detected by immunohistochemistry, Western blotting and real-time PCR. RESULTS: Under light microscope, the pathologic changes included myocardial interstitial edema, inflammatory cells infiltration, myocardial necrosis, and focal and patchy necrosis of myocardial fiber in VMC group. The expression of Spry1 protein in VMC group was lower than that in control group (P < 0.05). There was slightly decreased expression of Spry1 of the mRNA level in VMC group (P > 0.05). But the MAPK protein expression in VMC group was higher than that in control group (P < 0.05). CONCLUSION: The pathway of MAPK/ERK involving Spry1 protein accelerates the expression of collagen, which may contribute to arrhythmia, heart failure and even sudden cardiac death.

[Effects of restraint position on changes of diaphragmatic mechanical characteristic in rats].

OBJECTIVE: To observe effects of restraint position on the changes of diaphragmatic mechanical characteristic in rats, and try to explore the role of nitric oxide (NO). METHODS: Rat model of restraint position was established. Rats were divided into control group, restraint position 12h and 24h groups. The markers of respiratory functions in vivo and the biomechanical markers of diaphragmatic characteristic ex vivo were evaluated. Serum NO levels were measured with spectrophotometry. The expressions of nNOS and iNOS mRNA in diaphragm were detected using RT-PCR. RESULTS: Compared with control group, respiratory rate, tidal volume and minute ventilation were significantly decreased in the restraint position 12h and 24h groups. Pt of diaphragm significantly decreased and force-generating capacity reduced at low frequency stimulation in 12h group. Force-generating capacity over the full range reduced at low and high frequency stimulation in 24h group. Pt of diaphragm in control and restraint position groups increased after L-NNA pre-incubation. Force-frequency relationship after L-NNA pre-incubation reduced in 24h group. NO level in serum increased significantly in the restraint position groups. Diaphragmatic nNOS mRNA expression was upregulated significantly in the restraint position groups. CONCLUSION: Restraint position induces the decreasement of diaphragmatic contractility and the decreasement is mediated by NO from diaphragm or circulation blood.

[Effect of soft tissue crush injury on tensions of thoracic aortic rings in rats].

OBJECTIVE: To observe the effect of soft tissue crush injury on the tensions of thoracic aortic rings (TARs) in rats and to investigate the potential roles of nitric oxide in the change of the tensions. METHODS: Thirty adult SD rats were randomly divided into control group and crush injury (8 h and 16 h after injury) groups. Two kinds of TARs (one with endothelium and the other without endothelium) in vitro were prepared. In the TARs with endothelium, the tensions induced by phenylephrine (PE), acetylcholine (Ach), calcium ionophore A23187 and angiotensin II (AngI) were measured by the vascular tension detective technique. Then the TARs with endothelium were preincubated with nitric oxide synthase inhibitor N-nitro-L-arginine (L-NNA) for 20 minutes, the tensions induced by PE and Ang II were measured again. In the TARs without endothelium, the tensions induced by PE and Ang II were measured by the same method. RESULTS: In the TARs with endothelium, the tension of relaxation induced by cumulative doses of Ach and A23187 decreased significantly in 8 h and 16h groups. The tension of contraction induced by cumulative doses of PE and Ang II also decreased significantly (P<0.05). The tension of contraction increased after the preincubation with L-NNA. In the TARs without endothelium, the tension of contraction induced by PE and Ang II increased comparing to that of TARs with endothelium. CONCLUSION: The soft tissue crush injury can influence the tensions of TARs in rats and the vascular-derived NO can mediate the effects.

[The expression of cholecystokinin-octapeptide receptor in vascular endothelial cells induced by lipopolysaccharide].

OBJECTIVE: To investigate the expression of cholecystokinin-octapeptide receptor (CCK-R) mRNA, and observe the effect of lipopolysaccharide (LPS) on CCK-AR mRNA and CCK-BR mRNA expression in ECV-304. METHODS: The human umbilical vein endothelial cell line ECV-304 was cultured and treated with LPS in dosage of 0.01, 0.1, 1, 10 mg/L for 2 hours, or treated with LPS in dosage of 1 mg/L for 0.5, 2, 6, 12 hours. Reverse transcription-polymerase chain reaction (RT-PCR) was employed to examine the expression of CCK-AR mRNA and CCK-BR mRNA in ECV-304, and to analyse the sequences of the amplification products. RESULTS: Compared with control group, the expression of CCK-AR mRNA and CCK-BR mRNA was significantly upregulated in a dose-dependence manner after incubated with 0.01, 0.1 and 1 mg/L LPS for 2 hours (all P<0.05). However, the expression of CCK-AR mRNA showed no significant increase,while that of CCK-BR mRNA was increased, after being incubated with 0.01 mg/L LPS. The expressions of CCK-AR mRNA and CCK-BR mRNA in the 10 mg/L LPS group showed no significant difference compared with 1 mg/L LPS group (both P>0.05). The expression of CCK-AR mRNA and CCK-BR mRNA was significantly upregulated in a time-dependence manner after incubated with 1 mg/L LPS from 0.5 hour to 2 hours compared with control group (all P<0.05). After incubated with 1 mg/L LPS for 6 hours, the expression of CCK-AR mRNA and CCK-BR mRNA was significantly decreased compared with 2-hour group, but was still higher than that of control group (both P<0.05). Its expression was decreased further after being incubated with 1 mg/L LPS for 12 hours compared with the 6 hours group (both P<0.05), but showed no significant difference compared with the control group (both P>0.05). CONCLUSION: Both CCK-AR mRNA and CCK-BR mRNA are expressed in ECV-304. LPS can up-regulate the expression of CCK-AR mRNA and CCK-BR mRNA.

[Mechanism of acute liver injury induced by crushing hindlimbs in rabbits].

OBJECTIVE: To investigate the role of oxidative stress in acute liver injury during crushing hindlimbs in rabbit. METHODS: The crushing injury model in rabbit was established by intermittent crushing the hind limbs of rabbit with standard weight. The ALT and AST activities were spectrophotometrically measured. The weight ratio (wet/dry,W/D) of livers was measured with scale, and the pathologic changes were observed. Superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) and total anti-oxidant capacity (T-AOC) as well as malondialdehyde (MDA) level were spectrophotometrically measured. RESULTS: As compared with control rabbits, crushing hindlimbs of rabbits induced acute liver injury with the increase in ALT and AST activities in serum,which were 4.31 (P < 0.01) and 10.54 times (P < 0.01) of control group respectively, there were cellular swellings and slight congestion of hepatic sinuses. In addition,crushing hind-limbs elicited significant decrease in SOD,CAT,GSH-Px activity and T-AOC to 17%, 29%, 24% and 21% (P < 0.01) compared with control group respectively, whereas MDA level markedly enhanced. CONCLUSION: Crushing hindlimbs of rabbits induced acute liver injury and significant decrease in anti-oxidant capacity, the latter maybe play an important role in crushing hind-limbs of rabbits-elicited the acute liver injury.

[Change of nitric oxide in local muscle of crush injury hind-limbs in rats].

OBJECTIVE: To investigate the change of nitric oxide (NO) level in local muscles induced by crushing hind-limbs in rats. METHODS: The rat experimental model of hind-limb crushing injury was established by crushing the hind limbs of rats with standard weight for 5 hours, thereafter releving the standard weight for another 5 hours. The rats were randomly divided into sham group, crushing group, crushing and injecting aminoguanidine (AG) group, crushing and injecting L-arginine (L-Arg) group. The NOS activity and NO level in local muscles and serum were spectrophotometrically measured, and iNOS and eNOS protein expressions in local muscles were examined by immunohistochemistry. The weight ratio of wet to dry (W/D) of local muscles was measured and the pathologic changes were observed. RESULTS: The crushing hind-limbs induced serious primary and secondary injuries of local muscles such as rupture and rhadomyolysis of skeletal muscular fibers, interstitial vascular congestion and edema, and marked increase in W/D. The expressions of eNOS and iNOS were upregulated in local muscle in crush group compared with sham group. The NOS activity and NO level in local muscles and serum significantly increased. There was positive relationship between NO level and W/D in local muscles. With the usage of AG and L-arg, the hind-limb injuries seemed alleviated and aggravated, respectively. CONCLUSION: The crushing hind-limbs of rats elicited the upregulation of eNOS and iNOS protein expression, the enhancement of NOS activity and the excess production of NO, the latter of which was involved in the mediation of secondary pathological changes in local muscles.

[Inhibitory effect of cholecystokinin octapeptide on lipopolysaccharide-elicited inducible nitric oxide synthase expression in vascular endothelial cells].

OBJECTIVE: To investigate the effect of cholecystokinin octapeptide (CCK-8) on lipopolysaccharide (LPS)-elicited inducible nitric oxide synthase (iNOS) expression in vascular endothelial cells. METHODS: Human umbilical vein endothelial cell line (ECV-304 cells) was stimulated with vehicle (normal saline) or LPS in the presence (0.01, 0.1, 1 mg/L) or absence (0.1 mg/L) of CCK-8 (10(-6)-10(-8)mol/L). Nitric oxide (NO) level and cellular nitric oxide synthase (NOS) activity were determined with spectrophotometrically. The iNOS expression was detected with immunocytochemical technique and Western blot. RESULTS: Compared with normal saline, LPS significantly induced the upregulation of iNOS protein expression in the cultured ECV-304 cells, and NOS activity in ECV-304 cells and NO level in cultured media were increased. CCK-8 obviously inhibited above-mentioned effect of LPS in a dose-dependent manner. Whereas CCK-8 alone did not showed effect on iNOS protein expression, NO level and cellular NOS activity as compared with those values when vehicle was used. CONCLUSION: CCK-8 inhibited LPS-elicited iNOS expression and NO production in ECV-304 cells.

[Receptor mechanisms underlying the modulation of lipopolysaccharide-induced nuclear factor-kappaB expression in vascular endothelial cells by cholecystokinin octapeptide].

OBJECTIVE: To elucidate the receptor mechanisms underlying the modulation of lipopolysaccharide (LPS)-induced nuclear factor-kappaB (NF-kappaB) expression in human umbilical vein endothelial cell line ECV-304 cells by cholecystokinin octapeptide (CCK-8). METHODS: Human umbilical vein endothelial cell line ECV-304 cells were stimulated with vehicle, LPS, CCK-8 (10(-9)-10(-7) mol/L), CCK receptor non-specific antagonist proglumide, CCK-A receptor (CCK-AR) specific antagonist CR-1409 or CCK-B receptor (CCK-BR) specific antagonist CR-2945 singularly or in combination. The NF-kappaB p65 protein level was determined by Western blot and immunocytochemistry technique. RESULTS: LPS resulted in an increase in the up-regulatory expression and nuclear translocation of NF-kappaB p65 protein in ECV-304 compared with vehicle stimulation. CCK-8 obviously inhibited LPS-induced the changes in NF-kappaB p65 protein in a dose-dependent manner. The inhibitory effects of CCK-8 on NF-kappaB p65 protein expression were attenuated by proglumide>CR-2945>CR-1409. CONCLUSION: CCK-AR and CCK-BR are involved in the mediation of CCK-8 inhibitive regulation for LPS-induced NF-kappaB protein expression in ECV-04 cells, whereas the effect of CCK-BR are more than that of CCK-R.

Effect of cholecystokinin octapeptide on diacylglycerol-PKC signaling pathway in rat pulmonary interstitial macrophages stimulated by lipopolysaccharide.

AIM: To investigate the effect of cholecystokinin octapeptide (CCK-8) on the diacylglycerol-protein kinase C (DAG-PKC) signaling pathway in rat pulmonary interstitial macrophages (PIM) stimulated by lipopolysaccaride (LPS). METHODS: The PIM from rat lung tissues were isolated using the collagenase digestion method combined with alveolar lavage and pulmonary vessel perfusion. DAG content and PKC activity were measured by radioenzymatic assay. The translocation of PKCzeta was determined by semi-quantitative immunoblot analysis. RESULTS: CCK-8, at high concentrations (1 x 10(-6) - 1 x 10(-5) mol/L), decreased DAG content and inhibited PKC activity and PKCzeta translocation compared with that in rat resting PIM of a control group (P< 0.01). LPS increased DAG content, and promoted PKC activity and PKCzeta translocation (P< 0.01). CCK-8 decreased LPS-induced DAG content and inhibited LPS-induced PKC activity and PKCzeta translocation significantly at 1 x 10(-8) - 1 x 10(-5) mol/L (P< 0.01). This inhibitory effect of CCK-8 could be abrogated partly by proglumide (non-selective CCK receptor antagonist), CR-1409 (selective CCK-A receptor antagonist), and CR-2945 (selective CCK-B receptor antagonist) in a concentration-dependent manner (P< 0.01). CONCLUSION: CCK-8 was a negative modulator of the DAG-PKC signaling pathway in rat resting PIM, which is very important for maintaining body homeostasis. It significantly inhibited LPS-induced DAG content, PKC activity and PKCzeta translocation in a concentration-dependent manner. The CCK receptor, especially the CCK-A receptor, might play a major role in this process.

[Polymorphic analysis of four Y short tandem repeat loci in Han nationality of Hebei province in China].

OBJECTIVE: To investigate the distribution of the polymorphism of the Y-chromosomal loci DYS438, DYS439, GATA A7.1 and GATA A7.2 among Han population in Hebei province. METHODS: With the use of PCR followed by polyacrylamide gel electrophoresis and silver staining, the allele frequencies of these loci in 164 unrelated men of Han population were investigated. RESULTS: Four, five, five, four alleles were observed at the loci DYS438, DYS439, GATA A7.1 and GATA A7.2 respectively; the frequencies of these alleles ranged from 0.0359 to 0.6587, from 0.0179 to 0.4107, from 0.0122 to 0.4146 and from 0.0476 to 0.5238 respectively; the probability discrimination of these loci were 0.5121, 0.6811, 0.6679 and 0.6327 respectively. Seventy different haplotypes were found at these loci. Thirty-six different haplotypes appeared only once. The power of discrimination of these four loci was 0.9480. CONCLUSION: The results demonstrate that these loci(DYS438, DYS439, GATA A7.1 and GATA A7.2) are good genetic markers with high determination power and can be applied to individual identification, especially in paternity test and the detection of mixed samples.

Effect of lipopolysaccharide on expression and characterization of cholecystokinin receptors in rat pulmonary interstitial macrophages.

AIM: To investigate the effect of lipopolysaccharide (LPS) on the expression and the binding characteristics of cholecystokinin receptors (CCK-R) in rat pulmonary interstitial macrophages (PIMs). METHODS: The PIMs isolated from rat lung tissues were purified by the collagenase digestion method combined with alveolar lavage and pulmonary vessel perfusion. The expression of CCK-R mRNA was detected by RT-PCR and Southern blot analysis and the binding experiments were performed by radioligand binding assay (RBA). RESULTS: CCK-A receptor (CCK-AR) and CCK-B receptor (CCK-BR) mRNA were detected in rat PIMs and their RT-PCR amplified products had a size of approximately 1.37 kb and 480 bp, respectively. The relative expression of CCK-BR mRNA was higher than that of CCK-AR mRNA after incubation with LPS for 0.5, 2, and 6 h. The expression of CCK-R mRNA could be upregulated obviously by LPS. Southern blot analysis of RT-PCR amplified CCK-AR and CCK-BR mRNA products using [gamma-32P]ATP 5'-end-labelled probe showed specific hybridization bands. The specific binding of [3H]CCK-8S to rat PIM membranes was detected in the rats administered with LPS for 48 h, but not in normal rats. Scatchard analysis of the saturation curves suggested the presence of CCK-R with a high affinity (Kd = 0.68 +/- 0.28 nmol/L) and a low binding capacity (Bmax = 32.5 +/- 2.7 fmol/g protein) in rat PIMs. The specific binding of [3H]CCK-8S to rat PIM membranes was inhibited by unlabelled CCK-8S (IC50 = 2.3 +/- 0.8 nmol/L), CCK-AR specific antagonist CR1409 (IC50 = 0.19 +/- 0.06 micromol/L) and CCK-BR specific antagonist CR2945 (IC50 = 3.2 +/- 0.1 nmol/L). CONCLUSION: Two types of functional CCK-AR and CCK-BR existed in rat PIMs and their expression could be upregulated by LPS.

[Effect of peroxynitrite on the reactivity of rabbit pulmonary arteries in vitro].

To investigate the effect of peroxynitrite (ONOO(-)) on the reactivity of rabbit pulmonary artery, the responses of rabbit pulmonary artery rings (PARs) pre-incubated with ONOO(-) to endothelium-dependent and receptor-dependent relaxants ACh and ADP, endothelium-dependent and receptor-independent relaxant calcium ionophore A23187, endothelium-independent relaxant sodium nitroprusside (SNP) and alpha(1)-adrenoceptor agonist phenylephrine (PE) were observed in vitro in an accumulative manner. (1) Relaxations of PARs to ACh, calcium ionophore A23187 and ADP were markedly impaired with shift of accumulative dose-response curve of each agonist to the right. Inhibition of endothelium-dependent and receptor-dependent or independent relaxation by ONOO(-) was dose-dependent. (2) ONOO(-) incubation inhibited SNP-induced relaxation in a dose-dependent manner. (3) Contractile response of PARs to PE varied with the different doses of ONOO(-). In PARs pre-incubated with 0.5 mmol/L ONOO(-), contractile response was significantly enhanced with shift of PE accumulative dose-response curve to the left, whereas in PARs pre-incubated with 1.0 mmol/L or 2.0 mmol/L ONOO(-), it was markedly reduced with right shift of PE accumulative dose-response curve. (4) Vehicle of ONOO(-) had no effect on responses to each agonist.Decomposed ONOO(-) had minimal effect on the response to PE and ADP, in contrast, relaxation of PARs to ACh, A23187 and SNP were enhanced. These results indicate that ONOO(-) may contribute to regulatory disorder of pulmonary artery reactivity.

[Endogenous peroxynitrite mediates lipopolysaccharide-induced injury in cultured pulmonary artery endothelial cells].

This study, using cultured bovine pulmonary artery endothelial cells (BPAECs), was undertaken to investigate the roles of endogenous ONOO(-) in LPS-caused injury in endothelial cells. The fluorescent intensity of nitrotyrosine (NT), a specific marker of ONOO(-) generation, in BPAECs represented the content of endogenous ONOO(-) generation. The fluorescent intensity of NT and the number of NT positive cells were detected with flow cytometry (FCM), and the percentage of NT positive cells was calculated. The results are as follows. (1) LPS (1, 5 and 10 microg/ml) caused a marked increase in fluorescent intensity of NT in a dose-dependent manner, which was significantly increased compared to the vehicle group (P<0.01).The number and percentage of NT positive cells were markedly increased (both P<0.05 vs vehicle group). Aminoguanidine (AG), a selective inhibitor of inducible nitric oxide synthase (iNOS), inhibited LPS-induced increase in fluorescent intensity of NT in BPAECs. However, the number and percentage of NT positive cells had a tendency to reduce. (2) LPS brought about an enhancement in MDA content and the activity of LDH in cultured supernatant. AG reversed the enhancement in MDA content induced by LPS (P<0.01). In contrast, AG had a marginal effect on the activity of LDH. (3) LPS induced an increase in apoptotic rate in BPAECs in a dose-dependent manner. The number of apoptotic cells markedly increased as well. Some BPAECs stained with fluorescent probe ethidium bromide showed morphological features of apoptosis with chromatin condensation and nuclear fragmentation. AG reduced the apoptotic rate and the number of apoptotic cells, both of which were still higher than those of vehicle group (P<0.05). LPS led to inhibition of mitochondrial respiration and membrane potential in an accumulation manner. In conclusion, LPS caused injury to cultured BPAECs and increased the production of ONOO(-).The cytotoxicity of LPS may be mediated by the endogenous ONOO(-).