Effects of oxidative modification of lipoproteins on blood coagulation and fibrinolysis

AIM: To study the effects of oxidative modification lipoproteins on blood coagulation and fibrino-lysis in vitro. METHODS: Normal human plasma VLDL, LDL and HDL, which were isolated by density gradient ultracentrifugation method, were oxidatively modified by Cu²⁺ and HOCl method. N-VLDL, Ox-VLDL, N-LDL, Ox-LDL, N-HDL, Ox-HDL were added to the reaction system which consisted of mixed fresh normal plasma respectively, prothrombin time (PT), activated partial thrombplastin time (APTT), plasminogen activator inhibitor 1 (PAI-1), tissue plasminogen activator (t-PA) and platelet aggregation were measured according to the direction of the kits. RESULTS: The relative electrophoretic mobility (REM), absorbance at 234nm and TBARS of oxidized VLDL, LDL and HDL mediated by HOCl or Cu²⁺ were significantly higher than that of the control group (P<0.01). N-VLDL, N-LDL and N-HDL had no effect on PT, APTT, t-PA, PAI-1 and platelet aggregation. The PT and APTT of Ox-VLDL, Ox-LDL and Ox-HDL were significantly shorter than that of the control group (P<0.05 and P<0.01). The platelet aggregation of Ox-VLDL, Ox-LDL and Ox-HDL were significantly stronger than that of the control group (P<0.01). The Ox-VLDL and Ox-LDL were higher in t-PA and lower in PAI-1 than that of the control group (P<0.05 and P<0.01), but the Ox-HDL had no influences on t-PA and PAI-1 activity. CONCLUSIONS: N-VLDL, N-LDL and N-HDL have no effects on blood coagulation and fibrinolysis in vitro. Ox-VLDL, Ox-LDL and Ox-HDL enhance blood coagulation and thrombosis. Ox-VLDL and Ox-LDL enhance t-PA activity and decreased PAI-1 activity, but Ox-HDL does not affect the fibrinolysis activity.     

Influence of Nao-xue-bao on blood coagulation and platelet aggregation in rats

AIM and METHODS:To study the effect of Nao-xue-bao at three different doses on blood coagulation,platelet aggregation by observing the changes in activated partial thromboplastin time (APTT), prothrombin time (PT), antithrombin-Ⅲ(AT-III), fibrinogen(Fng), plasminogen(Plg) and platelet aggregation(PAG). RESULTS:Compared with thrombosis group, the rats treated with Naoxuebao showed that the plasma APTT,PT were longer, and the activity of AT-III was increased. The content of Fng was reduced, TT was longer, there was a negative correlation between Fng and TT. Furthermore PAG-1, PAG-5 and PAG-M were reduced. CONCLUSION: Nao-xue-bao could inhibit thrombosis in different keys of blood coagulation.     

Study on biological activity of thrombopoietinⅡ in vivo

AIM: To investigate the biological activity of thrombopoietin Ⅱ(TPOⅡ) in vivo, which consists of two new kinds of ligand binding with thrombopoietin receptor. METHODS: Purified ligandⅠof TPOⅡ, artificial compound ligandⅡ of TPOⅡand rhTPO were injected into purebred Babl/c mice respectively in 7 days by intraperitoneal injection once for a day. Then the biological activity of TPOⅡ was analyzed by measuring peripheral platelet counts by the end of the seventh day. RESULTS: On the seventh day, the platelet counts of mice treated by ligandⅠof TPOⅡ were higher than that in the negative control group(P＜0.05), while not significantly different from the platelet counts of mice treated by rhTPO(P＞0.05). On the fourteenth day, the platelet counts increased in two all experimental groups of TPOⅡcompared with negative control group(P＜0.01), while not significantly different from the platelet counts of mice treated by rhTPO too(P＞0.05). Moreover the platelet counts of mice in two experimental groups of TPOⅡ and the positive group showed increase with experimental days. CONCLUSION: The purified ligandⅠof TPOⅡ had obvious activity in increasing platelet production, which is not different from the effect of rhTPO.     

Effects of granulocyte colony-stimulating factor on the myocardial infarction in experimental rats

AIM: To investigate the effects of granulocyte colony-stimulating factor (G-CSF) on the myocardial infarction in experimental rats. METHODS: Rats were randomly divided into GT group and saline control group (SC).The rats of GT group were treated with G-CSF (10 μg/kg) once a day subcutaneously for 5 days and those of SC group were received saline.On the third day, both groups were injected with isoprenaline (ISO) interaperitoneally to develop acute ischemic model. The hearts were harvested from 2 weeks to 4 weeks after administration of ISO for histopathological examination. RESULTS: Compared with saline control group, G-CSF treatment group significantly reduced the scar size (P<0.05). We also found the regeneration of myocytes, smooth muscle and endothelial cells. CONCLUSION: G-CSF treatment could be benefical to the regeneration of infarcted myocardium and significantly reduce scar size and it could be used for therapeutic intervention of the acute myocardial infarction.     

Effects of different group B streptococci strains on platelet activation

AIM: To explore the ability of different group B streptococci (GBS) strains on inducing platelet activation. METHODS: Six strains of GBS, separated from the septic patients with thrombocytopenia, were used as the inducers. Light transmission aggregometry was used to measure platelet aggregation. Scanning electron microscopy (SEM) was performed to investigate the interaction of platelets with bacteria. The expression of platelet CD62P, Toll-like receptor 2 (TLR2) and TLR4 was determined by flow cytometry and Western blotting. Furthermore, the activity of platelet TLR2 (or TLR4) was blocked by anti-TLR2 (or anti-TLR4) monoclonal antibody, and the platelet aggregation induced by GBS was detected. RESULTS: Only 3 of 6 GBS strains isolated from the septic patients induced platelet aggregation and up-regulated the expression of CD62P and TLR2 in the platelets (P < 0.05), but not TLR4. Incubation with anti-TLR2 antibody, but not anti-TLR4 antibody, significantly blocked platelet aggregation induced by GBS.CONCLUSION: Some GBS strains from the patients are able to trigger platelet activation in vitro, and platelet TLR2 may play an important role in the interaction between GBS and platelets.     

Effects of imidapril on blood gas,oxidative stress and inflammatory factors in rats with acute lung injury induced by ammonium chloride

AIM: In this study, the rat lung injury model was induced by ammonium chloride for studying the effect of imidapril on blood gas, serum TNF-α, IL-6 and MDA concentrations, and AngⅡ and CD54 protein expression in rat lung tissue. METHODS: Male rats were randomly divided into 3 groups: control group, lung injury model group and drug group. The rats in control group were given saline (2 mL/kg), while the rats in lung injury model group were given 6% ammonium chloride (2 mL/kg). In drug group, imidapril (3 mg·kg^-1·d^-1) was given to the rats once daily for 1 week by intragastric gavage after given 6% ammonium chloride. On the 7th day, the rats were anesthetized with 2% so-dium pentobarbital. Abdominal aorta blood, venous blood and lung tissue were collected. The blood gas indexes and serum TNF-α, IL-6 and MDA concentrations were determined. The lung tissues were fixed and sliced, and the expression of AngⅡ and CD54 proteins was detected by immunohistochemistry. RESULTS: The PaCO₂ increased in lung injury model group compared with control group and drug group (P < 0.05).The expression of AngⅡ and CD54, and the concentrations of TNF-α, IL-6 and MDA also increased significantly (P < 0.01) in model group. Pulmonary edema, inflammation, alveolus congestion, hemorrhage and hyperplasia in model group were obvious compared with control group and drug group. CONCLUSION: Imidapril improves blood gas indexes, and reduces lipid peroxidation and inflammatory responses in the rats with lung injury induced by ammonium chloride.     

Polysaccharide extracted from laminaria japonica aresch inhibits platelet activation and protects endothelial cells

AIM: To study the relationship between the effects of polysaccharide L01 extracted from laminaria japonica aresch on platelet activation and endothelial cells. METHODS: A rat model of endothelial injury was established via injecting adrenaline. The percentage of platelet adhesion was evaluated by filtration method, the activation of platelet aggregation was observed on a glass plate with collodion membrane, the content of vWF in rat plasma was measured by ELISA, the damaged degree of aortic vascular endothelial was evaluated by immunity histochemistry. RESULTS: The percentage of platelet adhesion and aggregation in model group were higher than those in NS group from the 3th and 4th day during the model made (P<0.05, P<0.01). The percentage in both L01 high-dose group (50 mg/kg) and low-dose group (10 mg/kg) at the 4th and 5th day was lower than that in model group (P<0.05, P<0.01). The content of vWF in rat plasma in model group was higher than that in NS group and in L01 high-dose group at 4th day (P<0.05). The same results were presented by the comparison among model group and NS group, both L01 high-dose group and low-dose group at the 5th (P<0.05). The measure of intact endodermis lengths (μm) stained by immunohistochemistry demonstrated that the length in model group was shorter than that in NS group (P<0.05), whereas the length in L01 high-dose group and low-dose group was obviously longer than that in model group (P<0.05) at the 4th and 5th day. CONCLUSION: The inhibitory effect of L01 on platelet activation may be related with its protective effect on vascular endothelial cells.     

Effect of cGMP on voltage-gated potassium channel in pulmonary artery smooth muscle cells from rats exposed to chronic hypoxia

AIM: To investigate the effect of cGMP on voltage-gated potassium channel in pulmonary artery smooth muscle cells (PASMCs) from rats exposed to chronic hypoxia. METHODS: (1) Wistar rats were randomly divided into control group (group A) and chronic hypoxia group (group B). Then group B received hypoxia 8 hours per day for 4 consecutive weeks. (2) Single PASMC was obtained via acute enzyme separation method. (3) Conventional whole-cell patch clamp technique was used to record resting membrane potential (Em) and ion currents of voltage-gated potassium channel. The changes of ion currents of voltage-gated potassium channel before and after applying cGMP (1 mmol/L), an agonist of protein kinase G (PKG), and cGMP plus H-8 (1 mmol/L), an inhibitor of PKG were compared between two groups. RESULTS: The Em of group B were significantly lower than that of group A. The ion currents of voltage-gated potassium channel in group A and group B were all significantly inhibited by cGMP [control group: from (118.0±5.0) pA/pF to (89.9±16.5) pA/pF, n=6, P＜0.05;chronic hypoxia group: from (81.0±5.0) pA/pF to (56.8±9.1) pA/pF, n=6, P＜0.05]and these effects were reversed by H-8 [control group: from (119.2±10.3) pA/pF to (117.8±9.1) pA/pF, n=6, P＞0.05;chronic hypoxia group: from (96.8±6.2)　pA/pF to (98.0±2.2)　pA/pF, n=6, P＞0.05]. CONCLUSIONS: The currents of voltage-gated potassium channel was inhibited by chronic hypoxic. The inhibitory effect of cGMP on currents of voltage-gated potassium channel in PASMCs from both normal and chronic hypoxic rats may be probably through the phosphorylation of voltage-gated potassium channel.     

Role of kisspeptin/GPR54 signaling pathways in prompting formation of precocious puberty

AIM: To explore the role of kisspeptin/GPR54 signaling pathway in the pathogenesis of precocious puberty based on female precocious puberty rat model induced by the single dose of danazol. METHODS: Female SD rats aged 3 d were randomly divided into normal group, vehicle group and model group. On the 5th day, the model rats were given a single subcutaneous injection of danazol with ethanol and ethylene glycol mixture. All rats were executed on 15 d, 25 d, 30 d, 35 d and 40 d, and the samples were collected to observe the sexual organ development. The levels of E₂, FSH and LH in peripheral blood were measured by ELISA. The Kiss-1 mRNA expression of Kiss-1, GPR54 and GnRH in hypothalamus was detected by real-time PCR. The kisspeptin expression in rat hypothalamus was observed by immunofluorescence. RESULTS: The time for puberty onset and sexual maturation in the model rats was significantly earlier than that in normal group and vehicle group. On days 25 and 30, the levels of peripheral sex hormones and uterine coefficients in model group were significantly higher than those in normal group and vehicle group. On days 25 and 30, the ovarian morphological development in the model rats was significantly earlier than that in normal group. On day 25, the mRNA expression of hypothalamic Kiss-1 and GnRH, and kisspeptin expression of hypothalamic arcuate nucleus in the model rats significantly increased compared with normal group and vehicle group. On day 30, kisspeptin expression of hypothalamic arcuate nucleus in the model rats decreased compared with normal group and vehicle group. On day 35, the mRNA expression of Kiss-1 and GnRH in the model rats decreased compared with normal group and vehicle group. The mRNA expression of GPR54 had no obvious difference among all groups. CONCLUSION: The Kiss-1 mRNA and kisspeptin expression in the model rats with precocious puberty is significantly increased in the hypothalamus during onset of puberty, suggesting that kisspeptin is an initiating factor for precocious puberty. Kisspeptin/GPR54 signaling pathway may play an important role in the occurrence of precocious puberty.     

Antiplatelet aggregation of naringenin via cyclic nucleotide signaling:in vitro studies

AIM:To investigate effect of naringenin on ADP-induced platelet aggregation and its possible mechanism.METHODS:The levels of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) were measured in the platelets with ADP stimulation using ELISA in the presence or absence of different concentrations of naringenin.The effect of naringenin at different concentrations on the change of phosphodiesterase (PDE) activity was measured by high efficiency liquid chromatography.The effects of naringenin at different concentrations on phosphorylation of vasodilator-stimulated phosphoprotein (VASP) at positions Ser157 and Ser239 in washed platelets with ADP stimulation were analyzed by Western blot.The phosphorylation of VASP at Ser239 was also analyzed in the presence of protein kinase A (PKA),protein kinase G (PKG),or protein kinase C (PKC) inhibitors before incubation with naringenin.The platelet aggregation was measured in the presence of PKA or PKG inhibitors before incubation with naringenin.RESULTS:Naringenin elevated cGMP levels significantly but not cAMP levels in the platelets with ADP stimulation in a dose-dependent manner.Naringenin inhibited PDE activity.Naringenin increased the phosphorylation of VASP at Ser239 in a dose-dependent manner in the platelets with ADP stimulation but only modest changes in the phosphorylation at position Ser157.The phosphorylation level of VASP at Ser239 position was inhibited when the platelets were treated with PKA inhibitor before incubation with naringenin.Incubation of platelets with neither PKG nor PKC inhibitors before treatment with naringenin affect the phosphorylation of VASP at Ser239.Pretreatment with PKA inhibitor but not PKG inhibitor significantly reversed the antiplatelet aggregation by naringenin in ADP-stimulated platelets.CONCLUSION:Naringenin may inhibit platelet activation through the elevation of cGMP-and PKA-mediated VASP phosphorylation.     

Effects of cotransplantation of rat bone marrow mesenchymal ste m cells and bone marrow on hematopoiesis

AIM:To investigate effects of rBMMSC on he matopoiesis and immune reconstitution after allo-hematopoietic stem cells transp lantation (HSCT).METHODS:Allogeneic BMT model from Fischer344 rats (RT-1Al) to W istar rats (RT-1Au) was established.The effects of MSCs on hematopoietic recons titution and immune reconstitution were studied by observing the survival rate,peripheral blood counts,thymus counts,spleen counts,bone marrow counts and im mune function analysis at 30 days after transplantation.RESULTS:1.Cotransplantation of MSCs and bone marrow (BM) was d emonstrated to improve hematopoietic reconstitution.Lymphocyte and platelet cou nts in peripheral blood in cotransplantation groups were higher than those in co ntrol groups.More bone marrow neucleated cells were also observed in cotranspla ntation groups.2.Cotransplantation of MSCs and BM improved immune reconstituti on.First,overall thymic cellularity and spleen cellularity significantly incre ased in cotransplantation groups at day 30.Secondly,cotransplantation improved immune functional recovery.Non-specific lymphocytes proliferation reaction ind uced by ConA and LPS increased in cotransplantation group,and so did for alloge neic mixed-lymphocyte reaction.CONCLUSION:Hematopoietic reconstitution and immune reconstituti on were significantly enhanced by MSCs cotransplanted with BM.     

Effect of nitric oxide on adiponectin-induced inhibition of platelet aggregation in hyperlipidemia rats

AIM: To investigate the mechanism that adiponectin inhibits platelet aggregation via nitric oxide (NO) signaling pathway. METHODS: Adult rats were fed with normal or high-fat diet for 14 weeks. Their platelets were immediately isolated and treated with or without recombinant full-length adiponectin (rAPN). The platelet aggregation, NO and superoxide production, endothelial nitric oxide synthase (eNOS)/inducible NOS (iNOS) expression, and antioxidant capacity were determined. RESULTS: Treatment with rAPN inhibited platelet aggregation induced by hyperlipidemia (P<0.05). Interestingly, total NO, a crucial molecule depressing platelet aggregate and thrombus formation, was significantly reduced, rather than increased in rAPN-treated platelets. Treatment with rAPN significantly decreased superoxide production by 62% (P<0.05) and increased antioxidant capacity by 38% (P<0.05) in hyperlipidemic platelets. Importantly, hyperlipidemia-induced reduction of eNOS phosphorylation and increase in iNOS expression were markedly reversed by rAPN treatment (P<0.05 and P<0.01, respectively). CONCLUSION: Adiponectin is an adipokine that inhibits platelet aggregation by enhancing eNOS activation and attenuating oxidative/nitrative stress including blockage of iNOS expression and superoxide production.     

Correlation analysis between visualization of hemorrheologic changes and platelet function in patients with acute coronary syndrome after percutaneous coronary intervention

AIM:To intuitionally observe the characteristics of blood rheology in the patients with acute coronary syndrome (ACS) after percutaneous coronary intervention (PCI) for 1 year to 3 years by micro-channel array flow analyzer (MC-FAN) combined with other platelet function indexes, and to explore the correlations between the test results of MC-FAN and platelet function. METHODS:This study brought 74 patients with ACS after PCI for 1 year to 3 years into test group, and 21 healthy subjects were enrolled as normal group. The levels of platelet aggregation test (PAgT), platelet adhesiveness test (PAdT), P-selectin, platelet-derived growth factor BB (PDGF-BB) and von Willebrand factor (vWF) were detected. MC-FAN HR300 was used to detect the transiting time (MC-FAN TT) of the blood passing through the model body capillaries. The differences of the test results between the 2 groups were compared, and the correlations between the results of MC-FAN and platelet function in the patients with ACS after PCI were also explored. RESULTS:Compared with normal group, the MC-FAN TT in test group was prolonged (P<0.01), the ability of erythrocyte deformation was weakened, and the leukocyte attaching the vascular wall and platelet adhesion and aggregation relatively increased. The levels of PAgT, PAdT, P-selectin and PDGF-BB in test group were all higher than those in normal group (P<0.01). No difference of vWF between the 2 groups was observed. The intergroup correlation analysis showed that there were correlations between MC-FAN TT and platelet function, in which 10 μL MC-FAN TT and 30 μL MC-FAN TT had the most significant correlation with P-selectin (r=0601, P<0.01; r=0334, P<0.01), 60 μL MC-FAN TT had the most significant correlation with PAgT (r=0527, P<0.01), and 100 μL MC-FAN TT had the most significant correlation with PAdT (r=0. 815, P<0.05). CONCLUSION:The visualization of hemorrheologic changes and platelet function in the patients with ACS after PCI are abnormal.There are correlations between MC-FAN TT and platelet function.The results of MC-FAN can objectively evaluate the blood rheology of the patients, and provide the reference for clinical treatment.     

Expression of cathepsin B and cystatin C and its potential role in diabetic rats

AIM: To observe the expressions of cathepsin B (CB) and cystatin C (CC) in different stage of diabetic rats and to investigates their potential roles.METHODS: Sixty rats were divided into diabetes mellitus group induced by intravenous injection of streptozotocin (55 mg/kg) and normal group injected with citrate buffer. Ten rats were sacrificed respectively at the end of fourth week, eighth week and sixteenth week in both groups. 24 h urine excretion was collected in rats before sacrifice. The blood and the kidney were also collected. The mRNA and protein expressions of CB and CC in kidney were detected by real time PCR and immunohistochemical staining, respectively.RESULTS: At the end of eighth week, the expression of Ccr, 24 h urinary protein excretion, CB, CC in diabetic rats increased significantly, compared to the results at the fourth week (P<0.01 or P<0.05). With the aggravation of diabetic nephropathy, the expressions of CC, colⅣ, FN and 24 h urinary protein excretion were up-regulated significantly (P<0.01 or P<0.05). The expression of CB in diabetic rats was up-regulated at eighth week significantly (P<0.01), whereas, at the end of sixteenth week it was down-regulated significantly (P<0.01). The 24 h urinary protein excretion, the expressions of colⅣ at protein and mRNA levels and FN were negatively correlated with CB (P<0.01).CONCLUSION: The unbalance of CB and CC exists in diabetic nephropathy renal tissue, which is likely to lead to the accumulation of extracellular matrix.     

Role of nitric oxide in aortic contractile function of renal hypertensive rats

AIM:To investigate the changes of aortic contractile function in renal hypertension with two-kidney, one-clip (2K1C) rats and its interrelation with nitric oxide (NO). METHODS:Animals were divided into 5 groups, sham operation group, 2K1C group, captopril group, L-arginine group and L-NAME group. At 4th week after operation, isometric tension changes of aortic rings were recorded, aortric cGMP content were also measured. RESULTS:Phenylephrine, acetylcholine, angiotensin Ⅱ and high potassium chloride solution-induced contraction was significantly increased, and aortric cGMP content was lowered in aortic rings from 2K1C rats compared with rings from sham rats. These changes were abolished in 2K1C rats treated with captopril. L-arginine partially reversed the change of aortic contractibility of 2K1C rats, and elevated aortic cGMP content. In 2K1C rats treated with nitric oxide synthase inhibitor L-NAME, aortric cGMP content were decreased further, but phenylephrine-induced contractile response were unaffected. After blockade of NO production with L-NAME, the maximal responses of aortric rings relaxation to sodium nitroprussidum were not significantly different in all five groups. CONCLUSION:These results indicate that the deficiency of nitric oxide production and the increase in the contractive factor in vascular tissue may contribute to changes in aortic contractile function of 2K1C rats.     

Changes of heme oxygenase-carbon monoxide system-in vascular calcification in rats

AIM:To investigate the change of heme oxygenase (HO)-carbon monoxide (CO)-cyclic guanosine monophosphate (cGMP) pathway in vascular calcification, to clarify the cellular and molecular mechanimsm in vascular calcification.METHODS:Vascular calcification model was established in rats by using vitamin D₃ and nicotine. The relative content of HO-1 mRNA, immunochemistry (IH) for HO-1, HO activity, HbCO formation and content of cGMP in aorta were measured.RESULTS:Compared to those of control rats, the HO-1 mRNA level in vessels of rats in VDN group(vascular calcification group) were decreased by 34.9% (P＜0.05);expression of HO-1 protein were decreased too, there were trace positive staining of HO-1 in the endothelium, and no obvious immunoreactivity in the medial layer;HO-1 activity was decreased by 60.6% (P＜0.01), CO concentration was decreased by 53.9% (P＜0.01) and cGMP content was decreased by 77.1% (P＜0.01) in vessels of rats in VDN group.CONCLUSION:There were obvious down regulation in HO-CO-cGMP pathway in calcified vessels.     

Effects of bortezomib-based therapy on hemostasis system and circulating microparticles in multiple myeloma patients

AIM：To investigate the changes of hemostasis, thrombosis and total microparticles (TMPs) in multiple myeloma (MM) patients receiving bortezomib-based induction therapy (bortezomib+adriamycin+dexamethasone, PAD). METHODS：The levels of TMPs were detected by flow cytometry in 38 newly diagnosed MM patients and 30 healthy people. The changes of the platelet, coagulation, anticoagulation, fibrinolytic activation and TMPs in the MM patients before and after PAD teatment were also studied.RESULTS：Before treatment, the values of FVIII:C and vWF:Rco in MM patient were elevated ［(152.89±31.14)% and (165.69±38.43)%］, the activation of platelet aggregation was inhibited ［(63.76±21.36)%］, and the PAI level increased ［3.98(1.63)U/mL］. Compared with the healthy people, higher concentration of TMPs was observed in MM patients ［(640.65±214.22)/μL vs (134.29±63.09)/μL, P<0.01］, and the level of TMPs was positively correlated with serum β2-MG (r=0.672, P<0.01).After PAD therapy, platelet aggregation activation was restored ［(77.83±15.62)%, P=0.01］, and PAI level decreased ［0.88(1.38)U/mL, P<0.01］. The level of TMPs also decreased, after 3 cycles of PAD, to the value of (184.25±93.35)/μL. CONCLUSION：MM patients were characterized by impaired platelet, coagulation and fibrinolysis functions, and increased level of TMPs. PAD restored platelet function, decreased the levels of PAI and TMPs, which might partially explain the low incidence of thrombosis in the MM patients receiving bortezomib-based treatment.     

Effect of myocardial ischemia on expression of natriuretic peptide receptors in rat medulla oblongata

AIM:To evaluate the expression of natriuretic peptide receptor A (NPR-A) and C (NPR-C), choline acetyltransferase (ChAT) and tyrosine hydroxylase (TH) in the ventral medulla oblongata after myocardial ischemia in the rats. METHODS:All rats were randomly divided into blank control group, sham group and myocardial ischemia group. After the myocardial ischemia model was established, the rats were sacrificed, and the expression of NPR-A, NPR-C, ChAT and TH in the rostral ventral medulla oblongata and caudal ventral medulla oblongata was detected by Western blotting on day 3, day 7, day 14, day 18 and on day 28. RESULTS:On the above days after modeling, the expression of NPR-A in ventral medulla oblongata of the rats was significantly increased (P<0.05). The expression of NPR-C was also increased, but later than NPR-A. The expression of TH was significantly decreased (P<0.05). The expression of ChAT in the rostral ventral medulla oblongata was lower than that in blank control group (P<0.05), and had no significant difference as compared with blank control group in the caudal ventral medulla oblongata. CONCLUSION:In medulla oblongata, the expression of NPR-A and NPR-C in the central cardiovascular region significantly increases after myocardial ischemia, while the expression of ChAT and TH decreases markedly. The natriuretic peptide, ChAT and TH may participate in the autonomic nervous control of cardiovascular system after myocardial ischemia.     

Effect of acupuncture on expression of EGF and bFGF in brain tissues of rats with traumatic brain injury

AIM: To observe the effect of acupuncture on the expression of epidermal growth factor (EGF) and basic fibrolblast growth factor (bFGF) in the brain tissues of rats with traumatic brain injury. METHODS: Thirty SD rats were randomized into sham-operated group, model group and acupuncture group. The model of traumatic brain injury was established by free drop impact. Acupuncture was performed to the rats in acupuncture group once every day and 7 days altogether. Brain histotomy was conducted after the treatment. Immunohistochemical method was adopted to test the protein expression of EGF and bFGF. RESULTS: Compared to sham-operated group, the expression of EGF in the brain tissues of model group decreased (P<0.01), and the expression of bFGF increased (P<0.01). Compared to model group, the expression of EGF and bFGF in acupuncture group increased obviously (P<0.01). CONCLUSION: Acupuncture significantly increases the expression of EGF and bFGF, and improves the repair of injured brain tissues. This might be one of the mechanisms by which acupuncture can treat traumatic brain injury and improve the nervous function.