The aim of this study was to observe the effect of a simulated liver tissue injury microenvironment on the directed differentiation of umbilical cord mesenchymal stem cells into hepatocytes with CYP450 metabolic activity in vitro, and to explore the mechanisms underlying this directed differentiation. Normal and damaged liver tissue homogenate supernatants (LHS and CCl4-LHS, respectively) were used as induction fluids. After induction for different durations, Western blot and RT-PCR were used to measure the protein and gene expression of the hepatocellular proteins AFP, CK18, ALB, and the CYP450 family. Simultaneously, the metabolic activity of CYP450 in hepatocytes was determined. Compared with the LHS and CCl4-LHS controls, the LHS and CCl4-LHS induction groups showed a significantly elevated protein and gene expression of AFP, CK18, ALB, CYP1A1/2, CYP2A6, CYP2C9, CYP2C19, CYP2D6, CYP2E1, and CYP3A4 (P < 0.05). The metabolic activity of CYP450 in hepatocytes was increased (P < 0.05). In addition, compared with the LHS group, the CCl4-LHS group induced cell differentiation more rapidly and with a higher efficiency. The results suggested that a liver injury microenvironment is conducive for the directed differentiation of umbilical cord mesenchymal stem cells into hepatocytes with metabolic enzyme activity.

Electromagnetic pulse (EMP) causes central nervous system damage and neurobehavioral disorders, and sevoflurane protects the brain from ischemic injury. We investigated the effects of sevoflurane on EMP-induced brain injury. Rats were exposed to EMP and immediately treated with sevoflurane. The protective effects of sevoflurane were assessed by Nissl staining, Fluoro-Jade C staining and electron microscopy. The neurobehavioral effects were assessed using the open-field test and the Morris water maze. Finally, primary cerebral cortical neurons were exposed to EMP and incubated with different concentration of sevoflurane. The cellular viability, lactate dehydrogenase (LDH) release, superoxide dismutase (SOD) activity and malondialdehyde (MDA) level were assayed. TUNEL staining was performed, and the expression of apoptotic markers was determined. The cerebral cortexes of EMP-exposed rats presented neuronal abnormalities. Sevoflurane alleviated these effects, as well as the learning and memory deficits caused by EMP exposure. In vitro, cell viability was reduced and LDH release was increased after EMP exposure; treatment with sevoflurane ameliorated these effects. Additionally, sevoflurane increased SOD activity, decreased MDA levels and alleviated neuronal apoptosis by regulating the expression of cleaved caspase-3, Bax and Bcl-2. These findings demonstrate that Sevoflurane conferred neuroprotective effects against EMP radiation-induced brain damage by inhibiting neuronal oxidative stress and apoptosis.

Objective:To observe the changes of pregnenolone(PREG) content in different brain region of scopolamine-induced learning and memory impairment rats model.Methods:The learning and memory impairment rats model was made by peritoneal injection of scopolamine.The learning and memory ability of rats were detected with Morris water maze;the PREG content in cortex of frontal lobe and hippocampus were detected by high performance liquid chromatography-mass spectrometry(HPLC-MS).Results:The learning and memory ability of model rats decreased significantly compared with control rats.Compared with control rats,the PREG contents in cortex of frontal lobe decreased significantly(P0.05);While PREG content in rats' hippocampus had no significantly changed.Conclusions: The PREG content in cortex of frontal lobe of scopolamine-induced learning and memory impairment rats decreased significantly,which infers that scopolamine may impair the rat's learning and memory ability by influenceing the synthesis of PREG.

目的 研究肝X受体(LXR)配体TO901317对海马神经元淀粉样前体蛋白(APP)、α-分泌酶(ADAM10)和β-分泌酶(BACE1)mRNA表达的影响及与β-淀粉样肽(Aβ)生成的关系.方法 大鼠海马神经元培养至第7天,在饲养液中加入2.0μmol/LTO901317,继续培养48h.应用RT-PCR方法研究海马神经元APP、ADAM10和BACE1等基因的mRNA的表达,放免法检测培养液Aβ含量的变化.结果 TO901317降低海马神经元APP和BACE1 mRNA表达(P＜0.01),减少培养液Aβ含量(P＜0.01),但不影响ADAM10 mRNA表达(P＞0.05).结论 TO901317激活LXR,能通过降低APP和BACE1的表达来减少海马神经元Aβ分泌.

Objective To investigate the effects of morphine dependence and withdrawal on neurosteroids and amino acid transmitters of rat amygdala. Methods Morphine dependence was induced by pretreatment with increasing doses of morphine for 7 days. Withdrawal was precipitated by naloxone (2mg/kg). Withdrawal syndromes were observed and scored. After decapitation, amygdala was dissected out. Nomadic and conjugated neurosteroids were extracted using liquid-liquid extraction and solid phase extraction. Concentrations of neurosteroids including dehydroepiandrosterone (DHEA), pregnenolone (PREG), allopregnanolone (AP), dehydroepiandrosterone sulfate (DHEAS) and pregnenolone sulfate (PREGS) were detected with HPLC-MS. Concentrations of glycine (GLY), glutamate (GLU) and gamma-aminobutyric acid (GABA) were quantitated by HPLC-ECD with pre-column OPA derivatization. Results Compared with saline control, the DHEA level in rat amygdala of morphine dependent group decreased by 33% (P＜0.01). Compared with naloxone control, the PREG and AP levels in rat amygdala of morphine withdrawal group increased by 45% (P＜0.05) and 42% (P＜0.05) respectively; the GABA level decreased by 18% (P＜0.01). Compared with morphine dependent group, the PREG and PREGS levels in rat amygdala of morphine withdrawal group increased by 60% and 40% respectively (P＜0.05); the glycine level decreased by 14% (P＜0.05). Conclusion The DHEA in rat amygdala may play a role in the development of morphine dependence but not involved in the manifestation of withdrawal symptoms. Other neurosteroids (including PREG, AP and PREGS) in rat amygdala seem to be involved in withdrawal but not in dependence. The synthesis and release of inhibitory amino acids in amygdala were depressed when withdrawal was precipitated by naloxone. The results suggest that different changes of neurosteroids and amino acids exist in stages of morphine dependence and withdrawal.

AIMTo establish the rat model of morphine-induced conditioned place preference (CPP) and to investigate the effects of morphine psychical dependence on the levels of neurosteroids in rat brain.METHODSRats were ip administered morphine 5 mg x kg(-1) for 10 days to induce CPP in morphine group. The concentrations of dehydroepiandrosterone (DHEA), pregnenolone (PREG), allopregnanolone (AP), dehydroepiandrosterone sulfate (DS) and pregnenolone sulfate (PS) in nucleus accumbens (Nac), hypothalamus (Ht), amygdale (A) and plasma of rats were determined with liquid chromatography-negative atmospheric pressure ionization mass spectrometry (LC-MS).RESULTSTrained with morphine for 10 days resulted in the acquisition of CPP in morphine group with the time that the rats spent in drug-pairing room was longer than that of control group. Compared with control group, morphine treatment could significantly decrease the contents of DHEA in Nac and plasma, decrease that of PREG in Ht.CONCLUSIONMorphine could induce the CPP in rats and affected the contents of some neurosteroids in rat brain, which suggests that endogenous neurosteroids might he related to the development of morphine dependence.

AIM:To investigate the effects of morphine dependence and withdrawal on the concentrations of neurosteroids in rat brain.METHODS:A method of simultaneous quantification of neurosteroids by gas chromatography-mass spectrometry (GC-MS) had been established.RESULTS:The chronic morphine administration (ip) resulted in a marked decrease in the brain concentrations of pregnenolone (PREG), progesterone (PROG), and pregenenolone sulfate (PREGS) in rats killed 6 h after the last treatment. In contrast, there were no significant effects of morphine dependence on the brain concentrations of allopregnanolone (AP), dihydroepiandrosterone (DHEA), and dihydroepiandrosterone sulfate (DHEAS). Naloxone-induced withdrawal produced a significant increase in the concentrations of PREG, PROG, AP, DHEA, PREGS, and DHEAS as compared with the control group.CONCLUSION:Morphine dependence and withdrawal affected the concentrations of neurosteroids in rat brain, which suggests that endogenous neurosteroids in brain might be related to the development of morphine dependence and withdrawal.

In rat peritonitis induced by ip carrageenin, depletion of circulating neutrophils (Neu) either by iv nitrogen mustard (1.2, 2.4, 3.6 mg/kg) or by exposure to 60Co (9 Gy) caused the decrease in number of Neu and amount of protein in exudate. However, in histamine-induced peritonitis, although the depletion of circulating Neu by 60Co decreased Neu emigration, the protein exudate was not reduced. Dexamethasone (0.15, 0.5, 1.5 mg/kg) im th before ip carrageenin suppressed both Neu emigration and protein exudate. On the other hand. dexamethasone only inhibited Neu emigration. but had no significant inhibitory effect on protein exudate induced by histamine. The results revealed tbat the increase in vascular permeability induced by carrageenin was dependent on the presence of circulating Neu, so that Neu emigration may be responsible for the exudation of plasma protein through the blood vessel wall. In addition. the primary action of dexamethasone may be an inhibitory action on Neu emigration and then control the vascular permeability.