Activation of corticotrophin releasing hormone-containing neurons in hypothalamic paraventricular nucleus contributes to sympathoexcitation in rats with congestive heart failure

AIM:To observe the expression of corticotropin releasing hormone (CRH) within the paraventricular nucleus of hypothalamus (PVN) and to explore the relationship between the activated CRH-containing neurons and sympathetic activity in rats with heart failure (HF).METHODS:Healthy male Sprague-Dawley (SD) rats were subjected to coronary artery ligation to induce HF,and chronic intracerebroventricular (ICV) infusion was performed by osmotic pump for 4 weeks.The rats in sham group and HF group were given vehicle (VEH;artificial cerebrospinal fluid 0.25 μL/h).The rats in HF plus treatment group were treated with CRH competitive inhibitor αh-CRH (15 mg/h).Meanwhile,the Lewis rats and Fischer 344 rats for control study also underwent coronary ligation to induce HF or sham surgery.After 4 weeks,left ventricular end-diastolic pressure (LVEDP) and maximum positive/negative change in pressure over time (±dp/dt_max) were determined.The right ventricular-to-body weight (RV/BW) and lung-to-body weight (lung/BW) ratios were calculated.The renal sympathetic nerve activity (RSNA) was recorded and the plasma norepinephrine (NE) level was measured.The expression of CRH in the PVN combined with the plasma adrenocorticotrophic hormone (ACTH) levels were measured.RESULTS:Compared with the sham-SD rats,the HF-SD rats had a greater number of CRH positive neurons in the PVN (accordingly the plasma ACTH levels were increased),accompanied by decreased±dp/dt_max and increased RSNA,plasma NE,LVEDP,lung/BW and RV/BW.However,ICV treatment with αh-CRH attenuated these changes in the HF-SD rats (P<0.05).Compared with the sham-Fisher 344 rats,the HF-Fisher 344 rats also had a greater number of CRH positive neurons in the PVN (accordingly the plasma ACTH levels were increased).In addition,they had significantly increased RSNA and plasma NE level,higher LVEDP,RV/BW and lung/BW,and lower±dp/dt_max(P<0.05).Compared with the SHAM-Lewis rats,the HF-Lewis rats had not significantly changed in the above parameters.CONCLUSION:In CHF,the CRH-containing neurons in PVN are activated,thus aggravating cardiac function by increasing sympathoexcitation.     

Role of central PGE2 on sympathetic excitation in chronic heart failure

AIM: To observe the effect of central prostaglandin E₂ (PGE₂) on sympathetic activation in chronic heart failure (CHF) and to explore the underlying mechanism. METHODS: Male SD rats were subjected to coronary artery ligation to induce heart failure (HF), and the intracerebroventricular infusion was performed by osmotic pump continuously. The rats in sham group and HF group were given artificial cerebrospinal fluid (0.25 μL/h). The rats in HF plus treatment group was given celecoxib (CLB; 20 mg/h). After 4 weeks, the levels of PGE₂ in cerebrospinal fluid (CSF), the sympathetic nerve excitability and cardiac function were measured, and the changes of corticotropin-hormone releasing hormone (CRH)-containing neurons activation and neurotransmitter contents in the hypothalamic paraventricular nucleus (PVN) were also determined. RESULTS: Compared with the sham-operated rats, the HF rats had raised level of PGE₂ in CSF, up-regulated renal sympathetic nerve activity and plasma norepinephrine, increased left ventricular end diastolic pressure, lung-to-body weight and right ventricular-to-body weight ratios, and decreased maximal increase and decreased rate of left ventricular pressure (P<0.05). In addition, the number of CRH positive neurons in PVN and the level of plasma adrenocorticotropic hormone were higher in HF rats than those in sham-operated rats (P<0.05). After administration of CLB into the lateral ventricle of HF rats, the contents of PGE₂ in CSF were significantly reduced, the number of activation CRH neurons in PVN was decreased, the excitability of sympathetic nerves was down-regulated and cardiac function was improved (P<0.05). Compared with the sham-operated rats, the content of glutamic acid in PVN of HF rats was increased, the content of γ-aminobutyric acid and the number of glutamate decarboxylase 67-positive neurons were decreased (P<0.05). After the CLB was given, the above indexes were reversed (P<0.05). CONCLUSION: These findings indicate that in CHF, the increased central PGE₂ may activate CRH-containing PVN neurons and contribute to the augmented sympathetic drive possibly by modulating the neurotransmitters within the PVN.     

Effect of ACTH on pain behavior and the level of brain-derived neurotrophic factor and corticotropin-releasing hormone in the hippocampus of rats with chronic pain

AIM: To observe the effect of adrenocorticotropic hormone(ACTH) on the levels of brain-derived neurotrophic factor(BDNF), trkB and corticotropin-releasing hormone(CRH) in the hippocampus of arthritic rats.METHODS: The BDNF immunoreactivity(IR) and CRH-positive neurons were stained with immunohistochemistry and in situ hybridization methods, respectively.RESULTS: The BDNF-IR, CRH mRNA-positive neurons in the contralateral hippocampus of the arthritic rats were increased significantly, which was decreased markedly by intraperitoneal injection of ACTH. However, the effect of ACTH was attenuated after adrenalectomy(ADX).CONCLUSION: These results suggest that BDNF and CRH in the hippocampus of arthritic rats were involved in the modulation of chronic pain, ACTH produced its analgesic effect by inhibiting the increase in BDNF and CRF level. Adrenal is critical to the analgesic action of ACTH.     

“信息园艺学论坛”在成都举行

由《园艺学报》编辑部和中国农业科学院蔬菜花卉研究所生物技术研究室共同发起和主办的“信息园艺学论坛”于2007年5月28～29日在成都举行。     

Effects of tyrosine phosphatase inhibitor on tau phosphorylation in vivo

AIM: To explore the effect of receptor tyrosine kinase system mediated by phosphotyrosine phosphatase (PTP) on tau phosphorylation in rat hippocampus. METHODS: Pervanadate (PVN), inhibitor of PTP or inhibitor of glycogen synthase kinase-3 (GSK-3), LiCl were injected into rat hippocampus by stereotaxy technique. The level of tau phosphorylation was detected by Western blot and immunohistochemistry after 24 h of injection. RESULTS: PVN significantly inhibited tau phosphorylation at PHF-1 epitope and the inhibition of tau phosphorylation by PVN was stronger than that of LiCl (P<0.01),and tau-1 epitope non-phosphorylated tau increased significantly in LiCl+PVN group than in control group (P<0.05). The level of total tau determined by R111d was significantly lower in PVN and LiCl+PVN treated groups (P<0.05) than that in LiCl and control groups. CONCLUSION: Tyrosine phosphatase inhibitor inhibited tau phosphorylation of hippocampus in rats. The underlie mechanism might be at least partially through the inhibition of GSK-3.     

Effect of hypothalamic PVN exogenous orexin-A on food intake in obese rats and regulation by NPY receptor signaling pathway

AIM:To investigate whether neuropeptide Y (NPY) receptor signaling pathway is involved in the regulation of orexin-A on food intake and glucose-sensitive (GS) neuronal excitability in the hypothalamic paraventricular nucleus (PVN) of diet-induced obese (DIO) rats. METHODS:Fluorescence immunohistochemistry experiment was used to observe the expression of orexin-A receptor (orexin receptor 1, OX1R) and NPY receptor Y5 (NPY-5R) in the PVN. The effect of orexin-A on the excitability of GS neurons in PVN was observed by single cell discharge recording. The cannula was implanted into the PVN of SD rats and DIO rats. The orexin-A, OX1R antagonist SB-334867 and NPY-5R antagonist CGP-71683 were injected through the cannula to observe the 0~2 h and 0~4 h food intake of the rats. RESULTS:The expression of OX1R and NPY-5R in the PVN of DIO rats was significantly higher than that in the SD rats. Orexin-A inhibited glucose-inhibited (GI) neurons and excited glucose-excited (GE) neurons in the PVN. However, the effects of orexin-A on GS neurons were partially blocked by the NPY-5R antagonist CGP-71683. Compared with the SD rats, orexin-A had more pronounced excitatory and inhibitory effects on PVN GS neurons in the DIO rats. Injection of orexin-A in the PVN increased food intake in the SD rats and DIO rats. However, the orexin-A-induced feeding was partially blocked by the NPY-5R antagonist CGP-71683. The effect of orexin-A on feeding was stronger in the DIO rats than that in the SD rats. CONCLUSION:The hypothalamic PVN orexin-A regulates food intake and GS neuronal excitability mainly through the OX1R signaling pathway, and NPY-5R signaling is also involved in this process, in which the regulatory effect on DIO rats is more sensitive.     

Effects of exogenous ADM on HPA axis in early stage of acute mechanical renal trauma

AIM: To explore the effects of exogenous adrenomedullin(ADM) on hypothalamus-pituitary-adrenal cortex (HPA)axis in the early stage of acute mechanical renal trauma.METHODS: Healthy adult Wistar rats were randomly divided into 4 groups: 8 in control group, 32 in trauma group, 32 in the group injected with ADM before trauma and 32 in the group injected with ADM after trauma. To induce renal trauma, the rats in the latter 3 groups were subjected to mechanical impact directly on the skin of renal region by a free-fall iron hammer. The rats in 2 treatment groups were injected with ADM (0.1 nmol/kg) intraperitoneally 10 min just before and after trauma,respectively. The rats in the 3 groups with kidney injury were executed in batches by drawing all the blood quickly in the hearts at the time points of 1 h, 6 h, 12 h and 24 h after trauma. The hypothalamus tissues were also collected. The expression of corticotropin-releasing hormone(CRH) in hypothalamus and the concentrations of adrenocorticotropic hormone(ACTH) and cortisol(CORT) in plasma were detected by immunohistochemical method and radioimmunoassay. RESULTS: The expression of CRH in hypothalamus and the concentrations of ACTH and CORT in plasma in trauma group,but were slightly higher than those in control group,but without statistical significance. The expression of CRH in hypothalamus at 1 h and 24 h, the concentration of ACTH in plasma at 12 h and CORT at 6 h,12 h and 24 h in the group injected with ADM before trauma significantly higher than those in trauma group and control group (P<0.05). The expression of CRH in hypothalamus at 1 h, 6 h and 12 h and the concentration of CORT in plasma at 12 h and 24 h in the group injected with ADM after trauma were obviously higher than those in trauma group and control group (P<0.05). CONCLUSION: Exogenous ADM stimulates HPA axis and activates the function of HPA axis markedly. However, the different layers of HPA axis have different responses to exogenous ADM. Injection of ADM before or after trauma has different effects on HPA axis.     

Effects of electrical stimulation of ventral septal area on discharge of pyrogen-treated thermosensitive neurons in preoptic anterior hypothalamus region of rabbits

AIM and METHODS: To investigate the effect of electrical stimulation of ventral septal area (VSA) on discharge of pyrogen-treated thermosensitive neurons in preoptic anterior hypothalamus (POAH) region, the discharging rate of thermosensitive neurons in the POAH region of 32 New Zealand white rabbits were recorded by using extracellular microelectrode techinque. RESULTS: (1) Intraceretroventricularly (i c v) injection of interleukin-1_β(IL-1_β) caused decrease of discharging rate of warm-sensitive neurons and increased in discharging rate of cold-sensitive neurons in POAH regions. (2) These effects could be reversed by electrical stimulation of VSA. CONCLUSION: VSA may play a central role of negative regulation in thermoregulation of pyrogen-treated animal.     

The central role of corticotropin-releasing hormone in stress-induced hyperthermia and LPS-induced fever in rats

AIM:To further investigate the role of central corticotropin-releasing hormone in stress-induced hyperthermia and lipopolysaccharide (LPS)-induced fever in the rat.METHODS:Test substances were administered intracerebroventricularly (icv) via a third ventricle cannula. Body temperature responses were monitored at 30 min intervals using colonic thermistor probes. Arginine vasopressin (AVP) level in the ventral septal area (VSA) determined by radioimmunoassay. RESULTS:In normal saline controls,rats were handled to take the colonic temperature,their body temperature significantly increased with a peak of(0.88±0.31)℃.The injection(icv)of α-helical CRH(9-41),a CRH-41 receptor antagonists,markedly attenuated the stress-induced hyperthermia within 90 min after injection of normal saline.LPS(300 ng,icv)stimulated a biphasic rise in the colonic temperature,the 3.5 h thermal response index(TRI_3.5)and AVP levels in the VSA of LPS-treated rats were higher than those of control rats.The AVP responses to LPS were inhibited significantly by blockade of central CRH actions using α-helical CRH(9-41)(5μg,icv)administered 10 min prior to LPS,whileα-helical CRH(9-41)(5μg,icv)resulted in exacerbated febrile responses to LPS(300 ng,icv). CONCLUSION:Central CRH plays an important role in stress-induced hyperthermia. The injection (icv) of α-helical CRH(9-41) enhances markedly LPS-induced fever in rats. CRH is a dual action molecule in LPS-induced fever, which itself mediates LPS-induced fever, at the same time, and limits the rise in body temperature during fever through actions of AVP in the VSA and glucocoticoids.     

Effects of antihistamine treatment on mast cell infiltration and c-Kit and SCF expression in liver tissues of rats with experimental hepatitis

AIM：To study the infiltration of mast cells and the expression of c-Kit and stem cell factor (SCF) in liver tissues of rats with experimental hepatitis and their changes after antihistamine (AH) treatment. METHODS：Thirty Wistar rats were divided into 3 groups at random: normal control (NC) group, chronic hepatitis (CH) group and AH group. The rat model of CH was established by composite factors (subcutaneous injection of carbon tetrachloride, accompanied by a diet containing high cholesterol, high alcohol, low protein and low choline). The rats in AH group were treated with ketotifen based on CH. At the end of the 4th week, blood samples were taken to determine plasma tryptase (TS) and histamine (HA) levels. Liver tissues were taken to detect HA content, observe the histological changes with HE staining and count the number of mast cells with toluidine blue (TB) staining. The mRNA and protein expression of c-Kit and SCF in liver tissues was detected by RT-PCR and immunohistochemistry. RESULTS：(1) The plasma TS and HA levels and liver HA content in CH group were significantly increased compared with NC group (P<0.05), while those in AH group were obviously decreased compared with CH group (P<0.05). (2) Fatty degeneration and fibrosis were observed in CH group under light microscope, but the hepatic injury was obviously attenuated in AH group. TB staining showed there were many degranulating and degranulated mast cells filled with purple granules around liver blood vessels and in fiber interval in CH group, and there were few purple granules in the cytoplasm of mast cells in AH group. The number of mast cells in CH group was increased compared with NC group (P<0.05), and that in AH group was reduced compared with CH group (P<0.05). (3) The results of RT-PCR showed that AH down-regulated the expression of c-Kit and SCF mRNA (P<0.05). The expression of c-Kit and SCF proteins in liver tissues increased in CH rats (P<0.05 vs NC group), decreased after AH treatment (P<0.05 vs CH group) and was positively correlated with liver HA content (P<0.05). CONCLUSION：These data suggest that an inflammatory pathway mediated by mast cell activation is involved in experimental hepatitis. Ketotifen can reduce mast cell degranulation by down-regulating the expression of mast cell membrane receptor c-Kit and its ligand SCF, thereby attenuating the liver inflammation.     

Electrical stimulation of POAH alters firing rates of IL-1β-treated thermosensitive neurons in the VSA in rabbits

AIM and METHODS: To investigate the functional connection between the preoptic anterior hypothalamus (POAH) and the ventral septal area (VSA) in fever mechanism, the firing rates of thermosensitive neurons in the VSA of 26 New Zealand white rabbits were recorded using extracellular microelectrode technique. RESULTS: The firing rates in both types of thermosensitive neurons in the VSA had no significant changes after intracerebroventricular (icv) injection of artificial cerebrospinal fluid(ACSF). When interleukin-1_β (IL-1_β) was given (icv), the firing rate of the warm-sensitive neurons was increased significantly and that of the cold-sensitive neurons was decreased remarkably. The effects of IL-1_β on the changes of firing rate in thermosensitive neurons of the VSA were reversed by electrical stimulation of the POAH. CONCLUSION: The roles of positive and negative thermoregulatory centers in the interaction between the POAH and VSA are closely linked during endogenous pyrogen induced fever.     

Effect of Astragalus injection on expression of calmodulin after hypoxia/hypoglycemia and reoxygenation in rat hippocampal neurons

AIM: To investigate the effect of Astragalus injection on the expression of calmodulin(CaM) after hypoxia/ hypoglycemia and reoxygenation in rat hippocampal neurons.METHODS: The hippocampal neurons were cultured for 8 days and divided into 4 groups: normal control group (normal control), hypoxia/hypoglycemia and reoxygenation group (model), Astragalus injection solution group (solution control) and Astragalus injection group ( Astragalus ).The cells in all groups were treated with reoxygenation and normal medium after deprived of oxygen and glucose for 30 min except normal control group.The method of immunohistochemistry was used to measure the number of caspase-3 positive neurons.The expression of CaM at mRNA and protein levels was measured at time points of 0 h, 0.5 h, 2 h, 6 h, 24 h, 48 h, 72 h and 120 h after hypoxia/hypoglycemia and reoxygenation by RT-PCR and Western blotting, respectively.RESULTS: No difference of the parameters at all time points between model group and solution control group was found.Compared with normal control group, the numbers and the percentages of caspase-3 positive cells at all time points obviously increased in model group except at 0 h and 0.5 h (P<0.05).Compared with model group, the numbers and the percentages of caspase-3 positive cells were decreased in Astragalus injection group except at 0 h and 0.5 h (P<0.05).Compared with normal control group, the protein expression of CaM in rat hippocampal neurons at all time points obviously increased in model group (P<0.05).However, the protein expression of CaM in rat hippocampal neurons at all time points obviously decreased in Astragalus injection group as compared with model group (P<0.05).Compared with normal control group, the mRNA expression of CaM in rat hippocampal neurons at all time points obviously decreased in model group (P<0.05).The mRNA expression of CaM in rat hippocampal neurons at all time points obviously increased in Astragalus injection group as compared with model group (P<0.05).CONCLUSION: Astragalus injection inhibits the protein expression of CaM, the calcium overload and the expression of caspase-3 after hypoxia/hypoglycemia and reoxygenation, thus inhibiting hippocampal neuronal apoptosis.     

Nucleus tractus solitarius participates in regulation of paraventricular nucleus vasopressinergic neurons on gastric ischemia-reperfusion injury in rats

AIM: To investigate the role of the nucleus tractus solitarius (NTS) in the regulation of paraventricular nucleus (PVN) AVP-ergic neurons on gastric ischemia- reperfusion injury (GI-RI). METHODS: Male SD rats were used in experiments. The celiac artery were clamped for 30 min and reperfused 1 h by removal of the clamp to obtain the ischemia-reperfusion state. The mechanism was analysed with nucleus electrical stimulation, electrolytic lesion and nucleus microinjection technique. RESULTS: Microinjection of arginine-vasopressin (AVP) into PVN obviously attenuated the GI-RI and dose-dependent effects were observed (r=-0.477, P<0.05) ; NTS lesion or microinjection of AVP antagonist into NTS both eliminated the attenuate effect of electrical stimulation of PVN on GI-RI. The effect of microinjection of AVP into NTS was similar to microinjection of AVP into PVN. CONCLUSION: The NTS participates in regulation of PVN AVP-ergic on GI-RI, which is mediated by the AVP receptor in the NTS.     

Effects of Qiancaofang fumigation on expression of YAP/Smad3 in rats with knee osteoarthritis

AIM: To observe the effects of Qiancaofang fumigation on the expression of Yes-associated protein (YAP) and Smad3 in the cartilage of the rats with knee osteoarthritis (KOA), and to investigate the protective effects and mechanisms of Qiancaofang fumigation on the cartilage of the rats with KOA. METHODS: SD rats (n=32) were randomly divided into 4 groups:control group, model group, Chinese medicine group and hyaluronic acid (HA) group. The improved Hulth method was used to construct the rat model of KOA in model group, Chinese medicine group and HA group. The rats in Chinese medicine group were treated with Qiancaofang fumigation. The rats in HA group were treated with intra-articular injection of HA. After treatments, the cartilage tissues and serum of the rats in each group were taken. Hematoxylin-eosin (HE) staining and Mankin's scores were measured. The expression levels of cartilage oligomefic matrix protein (COMP) and C-telopeptide of type Ⅱ collagen (CTX-Ⅱ) in the serum were detected. The method of TdT-mediated dUTP nick-end labeling (TUNEL) was used to observe the apoptosis of the cartilage cells. Immunohistochemistry was performed to detect the expression of YAP and high mobility group protein B2 (HMGB2). Western blot was used to detect the expression of YAP, Smad3, bone morphogenetic protein 2 (BMP2), Bax and Bcl-2. RESULTS: The results of HE staining showed that the cartilage cells in model group were disordered and the structure was not clear. Compared with model group, the cartilage surface in Chinese medicine group was more smooth, the structure was clearer, and the staining of the cartilage matrix was more uniform. Compared with model group, the Mankin's scores in Chinese medicine group and HA group were significantly decreased (P<0.05), the serum concentration of CTX-Ⅱ was significantly increased, the serum concentration of COMP was significantly decreased, and the apoptosis rate of the cells was decreased (P<0.05). The results of immunohistochemistry and Western blot showed that the expression levels of YAP, HMGB2, Smad3 and Bcl-2 were increased in Chinese medicine group and HA group, and the expression levels of BMP2 and Bax were decreased as compared with model group (P<0.05). CONCLUSION: Qiancaofang fumigation relieves KOA partially through the YAP/Smad3 signaling pathway.     

c-Fos expression in spinal trigeminal tract neurons of rats induced by intrapericardiac injection of algogenic chemicals

AIM: To identify the correlation between intrapericardial injection of allogeneic chemicals and activation of the rat spinal trigeminal tract (STT) neurons.METHODS: Adult male Wistar rats were anesthetized with urethane and divided into 3 groups: inflammatory exudate solution (IES) group, receiving intrapericardial infusion of IES; negative control (saline) group, receiving intrapericardial infusion of saline; and sham group, undergoing the same surgical procedure without intrapericardial infusion. The expression of c-Fos in the neurons of the cervical spinal cord and brain stem, particularly in the region of the trigeminal sensory nuclear complex, including the principal sensory trigeminal nucleus (Pr5VL), subnucleus oralis (Sp5O), subnucleus interpolaris (Sp5I) and subnucleus caudalis (Sp5C), was analyzed by immunohistochemistry as an index of neuronal activation. RESULTS: Compared with saline group and sham group, the number of c-Fos-positive neurons in IES group increased significantly (P＜0.05). c-Fos-positive neurons were mainly found in the dorsal horns of laminae I-V at C2, as well as at the rostral edge of the Pr5VL, Sp5O, Sp5I, and Sp5C. The number of c-Fos-positive neurons gradually increased from bregma to interaural line at the pyramidal decussation. Interestingly, fewer c-Fos-positive neurons were observed on the right side than that on the left (P＜0.05).CONCLUSION: Intrapericardial injection of algogenic chemicals activates STT neurons, possibly underlying the phenomenon whereby cardiac ischemia causes craniofacial pain.     

Transplantation of human amnion epithelial cells improves learning and memory function in Alzheimer's disease-like pathology rat model

AIM: To observe the treatment effect and its immune regulation of human amnion epithelial cells (hAECs) on Alzheimer's disease (AD)-like pathology rat model. METHODS: The hAECs were isolated from amnion with trypsin digestion, and the phenotype of hAECs was analyzed by flow cytometry. SD rats (n=48) were randomly divided into sham control group, model group, medium group and hAECs group. AD-like pathology rat model was induced by bilateral intraventricular injection of lipopolysaccharide (LPS). hAECs (5×10⁵) were injected into the hippocampus of the AD-like pathology rats. At 2 weeks after transplantation, the animals were tested by Morris water maze to observe the function of learning and memory. The pathological change of the brain was observed by HE staining. The expression of amyloid β-protein 42(Aβ42) and Tau protein and the level of acetylcholine (ACh) in the injury brain were determined by immunohistochemistry. The survival and differentiation of hAECs in the hippocampus were measured by immunofluorescent technique. The percentages of lymphocyte subsets in the peripheral blood mononuclear cells were analyzed by flow cytometry. The contents of serum cytokines were detected by cytometric bead array. RESULTS: Compared with model group and medium group, hAECs group showed shortened escape latency (P<0.01), increased frequency of going through the platform (P<0.05), reduced loss of hippocampal neurons, decreased expression of Tau protein and Aβ42 in the hippocampus (P<0.05), increased ACh level in the hippocampus (P<0.05), decreased percentages of Th1 and Th17 subsets, increased percentages of Th2 and Treg cells (P<0.05), decreased concentrations of IFN-γ and IL-2 in the serum, and increased concentration of IL-4(P<0.05). CONCLUSION: hAECs improve the cognitive learning and memory function and alleviate pathologic damage of hippocampus through immune regulation in AD-like pathology rats.     

Changes of adenyl cyclase and phosphodiesterase activities at different time point in hypothalamus of rats with fever and hypothermia

AIM: To observe the changes of adengl cyclase (AC) and phosphodiesterase (PDE) activities of at different time point in hypothalamus of rats with fever and hypothermia. METHODS: Radioisotope method was used to measure the activity of AC and PDE. RESULTS: The fresh yeast caused rats fever after subcutaneous injection 4 h (P<0.01). AC activity reached a peak value at 3rd h after making model (P<0.05), and PDE activity increased slightly in the full process of experiment action; Aminopyrine induced rats hypothermia stat15 min after peritoneal injection (P<0.01). AC activity was higher than normal animal a 15th minute after the injection of aminopyrine. But subsequently AC activity decreased rapidly with the lowest value at 45th minute after the injection (P<0.05). PDE activity fluctuated slightly within normal range in the full course of experiment. CONCLUSION: In fever model, it might be important cause of febrile response that AC activity in hypothalamus increased markedly, while PDE might be the factor causing long-term febrile response. In hypothermia model, the obvious decrease in AC activity indicating that cAMP content in hypothalamus might be related to hypothermia status.     

Neuronal apoptosis and the chance of apoptosis-related proteins in ovariectomied rats with the effect of App17-mer peptide

AIM: To observe the expression of apoptosis-related proteins in hippocampal neurons of ovariectomized (OVX) rats and explore the neuroprotective mechanism of the App17-mer peptide. METHODS: Female Wistar rats were randomly divided into three groups. Bilaterally ovariectomized rats with injection of App 17P peptide (3.5 μg in 0.1 mL/per rat, three times a week) formed the experimental group (17P+ OVX group). Anti-AIF, Bcl-2 and Bax antibodies were applied in the immunohistochemistry experiment. TUNEL was employed to detect apoptosis. RESULTS: The number of apoptotic neurons was clearly higher in hippocampal and cortex in OVX group than that in OVX+17P group. Immunohistochemistry demonstrated the increased expression of AIF, Bax in hippocampal neurons of OVX group. OVX group showed a significantly reduced expression of Bcl-2 in hippocampal neurons. Hippocampal tissue from OVX group showed the increased expression of AIF,Bax ,and showed diminished expression of Bcl-2 , treating with App17-mer peptide normalized the expression of these proteins. CONCLUSIONS: The expression of apoptosis-related proteins were abnormal in the OVX rats. App17-mer peptide normalized these changes ; Estrogen deficiency induced neuronal apoptosis. App17-mer peptide diminished apoptosis.     

Influence of Bcl-2 inhibitor on Astragalus injection-reduced expression of caspase-3 in rat hippocampal neurons with oxygen-glucose deprivation and reoxygenation

AIM: To observe the influence of Bcl-2 inhibitor on the expression of caspase-3 reduced by Astra-galus injection in rat hippocampal neurons with oxygen-glucose deprivation and reoxygenation (OGD/R). METHODS: The primary rat hippocampal neurons cultured in vitro for 8 d were chosen and randomly divided into 6 groups: normal control group, model group (OGD/R group), Astragalus injection group, Astragalus injection solvent (sterile deionized water)group, Bcl-2 inhibitor group and Bcl-2 inhibitor with Astragalus injection group. The cells in all groups were tested 24 h after they were treated with reoxygenation after deprived of oxygen and glucose for 30 min except normal control group. The cell type and rate of positive cells were observed by immunohistochemistry. The protein levels of Bcl-2 and cleaved caspase-3 in the hippocampal neurons were measured by Western blotting. The mRNA expression of caspase-3 was detected by RT-PCR. RESULTS: Compared with normal control group, the caspase-3 positive rate of the cells, the protein levels of Bcl-2 and cleaved caspase-3, and the mRNA expression of caspase-3 in model group enhanced significantly (P < 0.05). Compared with model group, the expression of Bcl-2 in Astragalus injection group obviously enhanced, while the caspase-3 positive rate of the cells, the protein level of cleaved caspase-3 and the mRNA expression of caspase-3 in the Astragalus injection group decreased significantly (P < 0.05). No significant difference in injection solvent group, Bcl-2 inhibitor group and Bcl-2 inhibitor with Astragalus injection group was observed (P > 0.05). The expression of Bcl-2 was decreased sharply in Bcl-2 inhibitor group and Bcl-2 inhibitor with Astragalus injection group. CONCLUSION: Bcl-2 inhibitor antagonizes the inhibitory effect of Astragalus injection on caspase-3 expression in rat hippocamal neurons with OGD/R, which may be one of the possible target for the inhibitory action of Astragalus injection on the apoptosis of rat hippocampal neurons induced by OGD/R.     

Correlation of intestinal endotoxemia,histaminemia and cellular immune function in patients with hepatitis B

AIM: To investigate the correlation of intestinal endotoxemia (IETM), histaminemia and cellular immune function in the patients with hepatitis B. METHODS: Peripheral blood was collected from patients with chronic hepatitis B (n=80) and healthy individuals (n=18). According to plasma endotoxin concentration, total patients were divided into two groups: ET positive and ET negative. Serum IL-10, IL-12, IFN-γ, IL-2, IL-4 concentrations were detected. In addition, the serum histamine (HA), tryptase (TS) and AP50 levels were studied. RESULTS: Compared to control group, the concentrations of IL-4 and IL-10 were increased, but IL-12 and IFN-γ were decreased obviously in total patients (P<0.05). The levels of IL-4 and IL-10 in ET positive group were higher than that in ET negative group (P<0.05). The level of IL-12 and IFN-γ had no statistical difference between two groups. AP50, HA and TS levels were increased significantly in total patients compared with control group, and the levels of ET positive were higher than that in ET negative group (P<0.05). Furthermore, in total patients, ET was correlated with IL-4, IL-10, AP50 and HA, respectively. HA was negatively correlated with IL-12 and IFN-γ, and correlated with AP50 and TS. In ET positive group, ET was correlated with IL-4, IL-10, AP50 and HA, respectively, which did not exist in ET negative group. CONCLUSION: AP50 may be a sign of IETM. IETM may be disbenefit to hepatitis B through activating complement, which leads to histaminemia and poor cellular immune function.