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Objective:To investigate the mechanism of cyclic AMP receptor protein (CRP) in regulating the siderophore enterobactin-related gene entC of carbapenem-resistant Klebsiella pneumoniae (CRKP). Methods:A mutant strain with crp gene deletion strain (Δ crp) and a complementary strain (c-Δ crp) were constructed using CRKP-27 as the wild-type strain. The influence of CRP on the secretion of siderophore by CRKP was analyzed by chrome azurol sulfonate (CAS) quantitative assay. RT-qPCR and lacZ reporter gene fusion assay were used to detect the regulatory effect of CRP on entC gene expression and its promoter. Electric mobility shift assay (EMSA) was performed to detect the binding of CRP to the entC promoter region and the binding sequence was analyzed by DNase Ⅰ footprinting assay. Results:The Δ crp and c-Δ crp strains were successfully constructed. Compared with the wild-type and c-Δ crp strains, the Δ crp strain could secrete more siderophore under both normal and iron-deficient conditions, but the difference was statistically significant only under normal condition ( P<0.05). The relative expression of entC gene at mRNA level was significantly lower in the Δ crp strain than that in the wild-type and c-Δ crp strains under both normal and iron-deficient conditions (both P<0.05). The promoter of entC gene in the Δ crp strain was less active than that in the wild-type and c-Δ crp strains under both normal and iron-deficient conditions (both P<0.05). EMSA showed that with the increase of CRP protein, the distance of entC probe from the positive pole was shortened and blocked. DNase Ⅰ footprinting assay further identified the specific binding site of the entC promoter region to CRP as 5′-AAGGTGATAAATGCGTCTCATTTTCAA-3′. Conclusions:The CRP protein in CRKP could specifically bind to the entC promoter region and directly promote its expression at transcriptional level.
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Objective@#To establish a rat model of preeclampsia (PE) in early pregnancy and to observe the changes in phenotype，pregnancy outcome and cognitive ability of offspring．@*Methods @#The pregnant rats were randomly divided into model group and control group．Ultra-low dose lipopolysaccharide (LPS) (0. 5 μg / kg) and an equal volume of normal saline were injected into the tail vein of pregnant rats on the fifth day of pregnancy．The levels of blood pressure ，12-hour urinary protein ，peripheral blood coagulation factors and placental cytokines in the two groups were measured．Furthermore，placental pathology，pregnancy outcomes，and cognitive abilities of offspring were observed. @*Results@#Blood pressure and urinary protein levels of model group were significantly higher than those of control group levels．Compared with the control group，the levels of platelet and antithrombin Ⅲ (AT Ⅲ) in the peripheral blood of pregnant rats in the model group were lower than those in the control group，while D-dimer was higher than that in the control group，the weight of the fetus and placenta in the model group decreased (P ＜0. 001) ，the expression levels of interleukin ( IL) -6，tumor necrosis factor α ( TNF-α) and interferon gamma (INF-γ) in peripheral blood increased，while the expression level of transforming growth factor β1 (TGF-β1) decreased(P＜0. 001) ．The water maze test showed that the latency of the offspring of the model group to the plat- form was longer than that of the control group (P＜0. 05) ，while the frequency of crossing the platform quadrant and the time of staying in the platform quadrant of the model group were lower than those of the control group (P < 0. 05 ) ．HE and PAS staining showed that there were infiltration of inflammatory cells in the basal layer of placenta， obvious decrease of blood vessels in labyrinthine area，slight edema of renal interstitium and degeneration of local renal tubular epithelial cells in the model group，while there were no above pathological changes in placenta and kidney in the control group．@*Conclusion@#A single injection of LPS in early pregnancy can successfully induce PE- related symptoms and adverse pregnancy outcomes such as fetal growth restriction and lead to the decline of cogni- tive ability of offspring.
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Objective @#To establish a laboratory model of heroin addiction in C57BL /6 mice based on associative learning mechanisms．@*Methods@#The black box and white box were selected as the memory training environment， and three behavioral training paradigms were studied : ① Pavlovian conditional position preference ( CPP) training paradigm，mice were placed in the white box for memory reinforcement training for 30 min after intraperitoneal injection of 0. 1 ml of corresponding concentrations (5. 0，10. 0，20. 0 mg / kg) of heroin at 9 :00 a．m．，and 24 h later 0. 1 ml of 0. 9% NaCl solution was injected intraperitoneally into the black box for training，and after the training，the mice were tested for their memory preference for the black and white boxes (movement time of different boxes) . ② A naloxone conditional position aversion ( CPA) training paradigm was conductedbased on the results of the CPP training paradigm. ③ Behavioral sensitization training paradigm，heroin addiction rating scale was established based on the statistical results of 3 behavioral experiments and the lethality of experimental animal disease mice after drug administration．Three different doses of heroin (5. 0，10. 0，20. 0 mg / kg) were selected to induce heroin addiction，and the most appropriate heroin concentration was selected by the results on the rating scale. @*Results@#In the CPP training paradigm，CPP was observed in all heroin groups (P＜0. 05，P＜0. 001，P＜0. 05) ．In the CPA training paradigm，the CPA induction rate was highest in the 10. 0 mg / kg heroin group compared to the control group (P ＜0. 01 ) ．In the behavioral sensitization training paradigm ，all heroin groups caused behavioral sensitization changes (P＜0. 001) ; but the 5. 0 and 10. 0 mg / kg heroin groups did not cause animal mortality．Overall，the 10. 0 mg / kg heroin group had the highest dose score on the rating scale．It could be used as a concentration to establish a stable experimental animal model of heroin addiction．@*Conclusion@#The study was effective in establishing a heroin addiction model in mice，and it was suitable for modeling drug concentration screening，with high animal survival rate and simple and practical．The combined learning mechanism can effectively shorten the model establishment period.
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Objective:To investigate the mechanism by which Fusobacterium nucleatum ( Fn) infection promotes TNF-α-induced inflammatory changes in colorectal cancer HCT116 cells. Methods:Fn-infected cells and TNF-α inflammation induction models were established and divided into 4 groups, namely uninfected control group, Fn-infected group, TNF-α induction group, and Fn+ TNF-α group. First, Fn was used to infect normal colonic epithelial cells hcoEPIC, colorectal cancer HCT116 and LoVo cells, the cell adhesion was detected 4 h later. Subsequently, HCT116 cells were induced with TNF-α for 3 h and then infected with Fn. After 24 h, the cell survival rate and cell damage were detected by CCK8 experiment and lactate dehydrogenase (LDH) viability assay. The ELISA method was further used to detect the expression of nuclear transcription factor NF-κB and cytokines IL-6, IL-8, and IL-1β in the cell and cell culture supernatant. Results:Fn has strong adhesion to colorectal cancer cells HCT116 and LoVo ( P<0.05), but basically does not show invasion. On the contrary, it has a higher invasion rate to normal colonic epithelial cells hcoEPIC after 24 h. Compared with the uninfected Fn group, the cell survival rate of the Fn-infected group was significantly reduced and the cell damage increased ( P<0.001). Three hours after TNF-α induction, Fn infection further promoted cell death and damage ( P<0.001). The expression of NF-κB in the Fn infection and TNF-α alone treatment group was significantly higher than that of the uninfected group ( P<0.001, P<0.05), and the NF-κB expression in the Fn+ TNF-α group was significantly higher than that of the control group and the single treatment group ( P<0.001). In the Fn infection and TNF-α treatment groups, the expressions of IL-6 and IL-8 were significantly higher than those in the uninfected group ( P<0.001), and IL-1β did not change significantly ( P>0.05). The expressions of IL-6, IL-8 and IL-1β in the Fn+ TNF-α group were significantly higher than those in the normal control group and the single treatment group ( P<0.05). Conclusions:Fusobacterium nucleatum can preferentially adhere to colorectal cancer cell HCT116, further promote TNF-α-induced cell damage and death, the expression and release of NF-κB and its downstream pro-inflammatory cytokines IL-6, IL-8, IL-1β.
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Objective To prepare nephritis dripping pills and study its pharmacodynamic effects. Methods The nephritis dripping pills were self-made, and the preparation was optimized by using orthogonal method. The model of chronic renal failure was established through resection of 5/6 kidney, the effect of nephritis dripping pills on rats was investigated by urinary protein and renal pathology analysis. Results The optimal preparation for nephritis dripping pills was as follows:taking PEG4000:PEG6000 =2:1, drug:matrix =1:3, setting temperature at 80 ℃ and dropping distance as 7 cm. The pharmacodynamic results showed that:compared with the model control groups, the nephritis dropping pills and renal failure pills significantly reduced the 24 h urine protein levels (P<0. 01),and the nephritis dripping pills were significant superior to renal failure pills (P<0. 05). The histopathological results showed that the renal tubular of treated groups remitted to normal, renal interstitial presented a small amount of inflammation cell infiltration and renal interstitial fibrosis was suppressed. Conclusion The preparation of nephritis dripping pills is relatively stable,and have good therapeutic effects on chronic renal failure,but the optimal dose should be further verified.
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BACKGROUND:Ola rats is a kind of rats with genovariation, who displays Wallerian degeneration after peripheral neuroaxonal damage that is slower than that normal 6J rats, thereby additional damage factor may help fully understand the property of Ola rats.OBJECTIVE: To observe the effect of acrylamide on the degeneration and regeneration of sciatic nerve medullated fibers following crush injury of C57BL/Ola (Ola) rat and C57BL/6J (6J) rat.DESIGN: Randomized controlled experiment.SETTING: Department of Neurology,Second People's hospital of Shenzhen; Department of Neurology of First hospital of Jilin University MATERIALS: This experiment was carried out in the neurological department in the University of Occupational and Environmental, Japan from January to June 1996. Twelve adult Ola rats and 6J rats were adopted and evenly randomly divided into experimental group and comparison group.METHODS: Rats were subjected to general anaesthesia, and then the proximal section of sciatic nerve was exposed and frustrated with hemostatic forceps for 10 s before suture. Rats in the experimental group were given intraperitoneal injection of acrylamide in a total dosage of 350 mg, which replaced by the same volume of physiological saline in comparison group.At 14 days after sciatic nerve torsion injury, all rats were anaesthetized again and the distal section of sciatic nerve was obtained and cut into slices, meanwhile the cross sectional area, the density and size frequency distribution of medullated fibers, as well as the number of medullated fibers in each nerve were determined.MAIN OUTCOME MEASURES: The density and size frequency distribution of sciatic nerve medullated fibers, as well as the number, the maximum diameter and the mean diameter of medullated fibers in two group of 0la rats and 6J rats.RESULTS: Totally 12 Ola rats and 6J rats entered the result analysis.① No Ola rat displayed Wallerian degeneration; But medullated fiber degeneration and following neonatal small diameter medullated fibers could be observed in 6J rats. ②In the experimental group, the total density of sciatic nerve medullated fibers in 6J rats was lower than that of Ola rat (P ＜ 0.05) ;with the total number of medullated fibers in 6J rats also less than that of Ola rat (P ＜ 0.01 ), which predominated by obviously reduced big diameter fibers (P ＜ 0.01); The mean diameter of medullated fiber in 6J rats was also obviously smaller than that of 0la rat (P ＜ 0.01 ).CONCLUSION: The Wallerian degeneration is extremely slow in Ola rat after torsion injury, which cannot be affected by acrylamide; while acrylamide has obvious inhibition on the axonal neogenesis in 6J rat after torsion injury.
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<p><b>OBJECTIVE</b>To explore the changes of brain energy metabolism following acrylamide (ACR) poisoning.</p><p><b>METHODS</b>Creatie kinase (CK), adenosine triphosphate (ATP), adenosine diphosphate(ADP), adenosine 5'-monophosphate(AMP) and glucose contents in brain were observed in O1a mice and 6J mice following ACR intoxication by enzyme analytical method.</p><p><b>RESULTS</b>ATP, CK and glucose levels decreased transiently in O1a mice, while ATP level in 6J mice was significantly decreased (1.76 mumol/g, P < 0.01), as compared to the control (2.53 mumol/g) but ADP and AMP were increased, glucose was decreased. The activity of CK in poisoned group (1.13 mumol/g, P < 0.01) was lower than that of control (3.16 mumol/g and lasted for 5 weeks).</p><p><b>CONCLUSION</b>The influence of ACR on O1a mice was slight and reversible but on 6J mice was severe and lasting. There was severe damage to the potential energy supply compensation, which might be the biochemical basis of neuron damage induced by acrylamide.</p>
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Animales , Ratones , Acrilamida , Intoxicación , Adenosina Trifosfato , Encéfalo , Metabolismo , Creatina Quinasa , Metabolismo Energético , GlucosaRESUMEN
ObjectiveTo explore the effect of brain derived neurotrophic factor(BDNF) on regeneration of distal axon in sciatic nerve after cfrush injury. MethodDistal axon was assessed by quantitavtive and qualitative analysis of pathology ResultLight microscope indicated thedensity of large diameter of peroneal-nerve was higher in study group compared with control group( P ＜0.01 ). No differences in density of littlediameter fiber were found between study and control group. EM showed the density of non-medullated fibers with diameter ＜0.5μm in studygroup was higher than that of control group. The numbers of layer in myelin was positively related to transverse axonal area( P ＜0.01 ) . The re-gression codfficient in study group wsa higher compared with control group( P = 0. 0023).ConclusionBDNF may promoted maturation ofsensoy nerve and formation of the myeline.
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Objective :To observate the axon changes in pathology of Ola mice,compared with those of 6Jmice. Methods:The peroneal nerve and sural nerve were studied by light-microscope and electronmi-croscope. Results :In light-microscope,the total transverse fascicular area was significantly large ;density ofmyelinated fibers was significantly less;the maximal diameter of myelinated fibers was significantly less;minimal diameter of myelinated fibers had no changens in 6J mice. The Ola mice were nomal. In electronmi-croscope observation, the neurofilament was accumulated within axons. Conclusion: In Ola mice treatedwith ACR,the like-Wallerian degeneration wes delayed. However,in 6J mice the neurofilament and mito-chondria accumulation was found within axons.