Role of Rho kinase in blocking the return of mesenteric lymph to improve vascular calcium sensitivity in hemorrhagic shock rats

AIM: To observe the role of Rho kinase in mesenteric lymph duct ligation or mesenteric lymph drainage to improve vascular calcium sensitivity in the rats subjected to hemorrhagic shock. METHODS: Male Wistar rats were randomly divided into sham group, shock group, shock+ligation (shock plus mesenteric lymph duct ligation) group and shock+drainage (shock plus mesenteric lymph drainage) group. After induction of shock (hypotension at 40 mmHg) for 3 h, the vascular rings of superior mesenteric artery (SMA) were prepared and used to measure the response to gradient calcium ions for determining the calcium sensitivity with a wire myograph system. In shock+ligation group and shock+drainage group, the vascular rings were incubated with Rho kinase agonist angiotensinⅡ or antagonist fasudil before the measurement of the response to gradient calcium ions. RESULTS: The calcium sensitivity of vascular rings in shock group was significantly lower than that in sham group, and that in shock+ligation group and shock+drainage group was significantly higher than that in shock group, but still lower than that in sham group. AngⅡ elevated the contractile activity of the vascular rings in response to gradient calcium ions and the pD₂, and fasudil significantly decreased the response to gradient calcium ions and E_max in shock+ligation group and shock+drainage group. At the same time, fasudil decreased the pD₂ in shock+ligation group. CONCLUSION: Rho kinase plays an important role in blocking shock mesenteric lymph return that improves calcium sensitivity.     

Effect of resveratrol on level of brain-derived neurotrophic factor in hippocampus of obese rats induced by ovariectomy and high-fat diet

AIM：To explore the effects of resveratrol on the level of brain-derived neurotrophic factor (BDNF) and the mRNA expression of estrogen receptor α (ERα) and estrogen receptor β (ERβ) in hippocampus of obese rats induced by ovariectomy and high-fat diet. METHODS：Fifty female Wistar rats, aged 3 months, were randomly divided into 5 groups: control (C) group, sham operation plus high-fat diet (H) group, ovariectomy plus normal diet (O) group, ovariectomy plus high-fat diet (O+H) group, and ovariectomy plus high-fat diet and treated with resveratrol (40 mg·kg-1·d-1) (O+H+R) group. Three months later, the blood was collected from the femoral artery to detect the serum concentrations of total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C) and estradiol (E2). The mRNA expression of ERα, ERβ and BDNF in the hippocampus was determined by real-time PCR. The protein level of BDNF in hippocampal tissues was detected by ELISA and Western blotting. RESULTS：Compared with C group, the serum levels of TC and LDL-C in H group were increased, and the hippocampal level of BDNF was decreased. The rats in O group had higher concentration of serum TC, and lower levels of serum E2 and the mRNA expression of ERα, ERβ and BDNF in the hippocampus than those in C group. Compared with C,H and O groups, the level of serum TC was higher, and the level of serum E2 and the expression of BDNF in the hippocampus was lower in O+H group. The mRNA expression of ERα and ERβ in hippocampus was also reduced as compared with C group and H group. After treated with resveratrol, the rats in O+H+R group showed lower level of serum TC, and higher levels of serum E2, hippocampal BDNF and mRNA expression of ERα and ERβ than those in O+H group. CONCLUSION：Ovariectomy combined with high-fat diet decreases the mRNA expression of ERαand ERβ and the level of BDNF in the rat hippocampus. Resveratrol improves the blood lipid metabolism and up-regulates the mRNA expression of ERα/ERβ and the level of BDNF in the hippocampus in obese rats induced by ovariectomy and high-fat diet.     

Influence of ovariectomy and estrogen replacement on gene expression profile of myocardium in rats

AIM:To investigate the influence of ovariectomy and estrogen replacement treatment on profile of gene expression in myocardium by cDNA microarray,and to characterize the targeting genes of estrogen.METHODS:cDNA microarray containing 1 400 rat cDNAs was used to study the genes differentially expressed in myocardium between sham (Ⅰ),ovariectomy (Ⅱ,OVX) and estrogen replacement treatment (Ⅲ,OVX+E2) group.Then down-regulated genes in myocardium of OVX rats were further confirmed by RT-PCR.RESULTS:177 genes were differentially expressed in myocardium between sham and OVX rats,with 91 genes up-regulated and 86 genes down-regulated in OVX rats.164 genes were differentially expressed in myocardium between OVX and OVX+E2 rats,with 113 genes up-regulated and 54 genes down-regulated in OVX rats.There were 54 genes differentially expressed in OVX compared to sham and OVX+E2.They are involved in membrane channels and transporters (18),cell receptors (9),intracellular transducers/effectors/modulator (7) and metabolism (6).Most of the genes (45) were down-regulated in OVX rats and up-regulated in OVX+E2 rats.RT-PCR test confirmed the results of cDNA microarray.CONCLUSIONS:Long-term estrogen replacement may influence the expression of genes involved in membrane channels and transporters,cell receptors,intracellular transducers/effectors/ modulator and metabolism.Long-term estrogen replacement has some beneficial effects on ionic concentration and cardiac function which partially comes from the results of influence of expression on Na+,K+-ATPase and Na+/H+ exchanger.Estrogen has an inhibitory effect on the expression of dopamine receptor,which partially clarify the myocardial protection of estrogen.     

Role of K+ channels in hypoxic pulmonary vasoconstriction in normal and chronic hypoxic rats

AIM:To investigate the role of K⁺ channels in the decreased hypoxic pulmonary vasoconstriction(HPV) in chronic hypoxic rats. METHODS:Blockers of three kinds of K⁺ channels, 4-AP(voltage dependent K⁺ channel blocker), TEA(Ca²⁺ activated K⁺ channel blocker), GLIB(ATP sensitive K⁺ channel blocker) were used in isolated perfused rat lungs to detect the role of K⁺ channels in HPV. RESULTS:In normal rats, 4-AP and TEA, but not GLIB, both elicited a significant increase in pulmonary artery baseline pressure, and also potentiated the acute hypoxic pulmonary vasoconstriction. In chronic hypoxic rats, the HPV is significantly decreased, while 4-AP, TEA, GLIB all elicited a significant but smaller increase in pulmonary artery baseline pressure. Additionally, all these three blockers potentiated the HPV stronger in chronic hypoxic rats than in control rats. CONCLUSION:The opening of Kv, K_Ca, K_ATP might modulate the hypoxic pulmonary vasoconstriction in isolated rat lungs, and the increase in this modulation by potassium channel in chronic hypoxic rats might play a role in its decrease in HPV.     

Role of TGF-β1/Smads and ERK expression in vascular remodeling induced by high-salt diet in Wistar rats

AIM: To investigate the role of transforming growth factor β₁ (TGF-β₁)/Smads and extracellular signal-regulated kinase(ERK) expression in vascular remodeling induced by high-salt diet in Wistar rats. METHODS: Wistar rats were randomly divided into 3 groups: normal control group (n=13), high salt (8%) model group and high salt+telmisartan group (n=13). Tail-cuff arterial pressure was determined every 2 weeks. After 24 weeks, the rats in high salt model group were divided into model animals with hypertension group (MH, n=12) and model animals without hypertension group (MN, n=12). The remodeling of aorta and mesenteric artery was observed by HE and Masson staining. In addition, the techniques of immunohistochemistry and real-time PCR were applied to detect the expression of proliferating cell nuclear antigen (PCNA), TGF-β₁, p-Smad2/3, p-ERK1/2 and Smad7 at both protein and mRNA levels. RESULTS: Compared with normal control group, blood pressure in MH group was much higher, and media thickness (MT) and collagen volume fraction (CVF) of arteries in MH and MN groups were higher.The mRNA expression of TGF-β₁, Smad2 and Smad7 in the aorta was significantly increased, and the protein levels of PCNA, p-ERK1/2, TGF-β₁ and p-Smad2/3 in the aorta and mesenteric artery media were elevated, but Smad7 decreased. After telmisartan treatment, MT and CVF were much lower,and the protein levels of PCNA, TGF-β₁, p-Smad2/3 and p-ERK1/2 were significantly reduced, whereas Smad7 was increased. CONCLUSION: The abnormal expression of TGF-β₁/Smads and ERK may be involved in the mechanism of remodeling of aorta and mesenteric artery induced by high-salt diet. Telmisartan prevents the vascular remodeling via regulating TGF-β₁/Smads and ERK signal pathways mediated by angiotensinⅡ type 1 (AT₁) receptor, at least in part.     

Effect of estrogen on the gene expression of caveolin-1 in rat vascular smooth muscle cells

AIM: To assess the effect of estrogen on the gene expression of caveolin-1 in rat vascular smooth muscle cells (VSMCs). METHODS: Wistar rats were ovariectomized and subjected to subcutaneous implantation of placebo pellets (OVX+V group) or estradiol pellets (OVX+E group). 2 weeks after implantation, the expression of caveolin-1 gene in endothelium-denuded aortic tissue was examined by RT-PCR. Furthermore, Northern blotting was used to analyze the mRNA expression of caveolin-1 in cultured rat VSMCs. RESULTS: RT-PCR showed that expression of caveolin-1 gene was significantly higher in OVX+E group than that in OVX+V group. Northern blot analysis showed that the mRNA expression of caveolin-1 was higher in VSMCs pretreated with 17β-estradiol (17β-E₂) than that in VSMCs without 17β-E₂ pretreatment. CONCLUSION: Estrogen up-regulates the gene expression of caveolin-1 in the vascular wall, partially indicating the cardiovascular effect of estrogen.     

Role of K+ channels in attenuation of pulmonary vasoreactivity following chronic hypobaric hypoxia in rats

AIM and METHODS: To determine the role of different K⁺-channels in attenuation of vasoreactivity of intrapulminary artery rings induced by chronic hypoxia. RESULTS: ①Acute hypoxia-induced pulmonary vasoconstriction (HPV) could be significantly attenuated by chronic hypobaric hypoxia for 15 days and for 30 days. ②HPV could be significantly potentiated by ATP-sensitive K⁺-channel (K_ATP) blocker or Ca²⁺-activated K⁺-channel (K_Ca) blocker, and the potentiated scope in chronic hypoxic group was much higher than that observed in control group. ③Delayed rectifier K⁺-channel (K_DR) blocker showed no effect on HPV in both control group and chronic hypoxic group. CONCLUSION: Both K_ATP and K_Ca play an important modulating role in HPV and its potentiation may be a critical mechanism for the attenuated vasoreactivity to acute hypoxia following chronic hypobaric hypoxia.     

Role of ATP-sensitive potassium channels in inhibitory effect of hydrogen sulfide on high glucose-induced injury in H9c2 cardiac cells

AIM: To investigate the roles of ATP-sensitive potassium (K_ATP) channels in high glucose-induced cardiac injury and the inhibitory effect of hydrogen sulfide (H₂S) on the cardiomyocyte injury. METHODS: The expression level of K_ATP channel protein was tested by Western blot. The cell viability was measured by CCK-8 assay. The number of apoptotic cells was observed by Hoechst 33258 nuclear staining. Mitochondrial membrane potential (MMP) was examined by JC-1 staining. RESULTS: After the H9c2 cells were treated with 35 mmol/L glucose (high glucose, HG) for 1~24 h, the protein level of K_ATP channel was significantly reduced at 6 h, 9 h, 12 h and 24 h, reaching the minimum level at 12 h and 24 h. Pretreatment of the cells with 400 μmol/L NaHS (a donor of H₂S) prior to exposure to HG for 12 h considerably blocked the down-regulation of K_ATP channels induced by HG. Pretreatment of the cells with 100 μmol/L mitochondrial K_ATP channel opener diazoxide, 50 μmol/L non-selective K_ATP channel opener pinacidil or NaHS obviously inhibited HG-induced injuries, leading to an increase in the cell viability, and decreases in the number of apoptotic cells and the MMP loss. Pretreatment with 100 μmol/L mitochondrial K_ATP channel antagonist 5-hydroxydecanoic acid or 1 mmol/L non-selective K_ATP channel antagonist glibenclamide attenuated the above cardioprotective effects of NaHS. CONCLUSION: K_ATP channels mediate the inhibitory effect of H₂S on HG-induced cardiac injury.     

JNK pathway promotes apoptosis of rat hippocampal neurons after cerebral ischemia and reperfusion

AIM:To investigate the effect of c-Jun N-terminal kinase(JNK) pathway on the apoptosis of hippocampal neurons after cerebral ischemia-reperfusion(IR) in SD rats. METHODS:Ninety rats were randomly divided into 5 groups:sham group, cerebral IR group,cerebral IR+JNK inhibitor(SP600125) group,cerebral IR+JNK agonist(anisomycin) group and cerebral IR+vehicle group. The brain samples were collected 24 h after reperfusion. The protein level of caspase-3 in hippocampal neurons was measured by immunohistochemical and Western blotting techniques. The mRNA expression of caspase-3 in the hippocampus was determined by real-time fluorescence quantitative PCR. The apoptosis of hippocampal neurons was detected by TUNEL staining. RESULTS:Compared with sham group, the expression of caspase-3 at mRNA and protein levels in cerebral IR group increased obviously(P<0.05). Compared with cerebral IR group, the expression of caspase-3 at mRNA and protein levels in cerebral IR+JNK inhibitor group decreased obviously(P<0.05), and those in cerebral group increased obviously(P<0.05). However, the expression of caspase-3 at mRNA and protein levels in cerebral IR+vehicle group had no obvious change(P>0.05).The apoptosis of hippocampal neurons in each group was consistent with the changes of caspase-3 at mRNA and protein levels. CONCLUSION:Activation of JNK pathway enhances caspase-3 expression in rat hippocampal neurons after cerebral IR,thus promoting the apoptosis of the neurons.     

全国设施蔬菜生产可持续发展学术研讨会在沈阳召开

会议由中国园艺学会主办 ,中国农业工程学会设施园艺工程专业委员会协办 ,沈阳农业大学园艺系承办 ,于 2 0 0 0年 4月 19日至 2 2日在沈阳农业大学召开。来自我国 13个省、自治区、直辖市的与会代表共 78人 ,会议论文 4 3篇 ,由沈阳农业大学学报专刊发表。经承办单位和与会者努力 ,会议圆满成功。开幕式由中国园艺学会副理事长李树德研究员主持 ,辽宁省科技厅、农业厅、沈阳市副食品局、沈阳农业大学的领导到会祝贺并发表讲话。会议就确定的主题进行了大会发言 ,小组讨论及现场考察。代表们欣喜地看到 ,近 2 0年来我国蔬菜设施生产迅猛发展 …     

Effects of hemorrhagic shock on BKCa channel tyrosine phosphorylation level in mesenteric artery in rats

AIM: To study the effects of hemorrhagic shock on BK_Ca channel tyrosine phosphorylation in rat superior mesenteric artery and the role of nitric oxide (NO) in BK_Ca channel tyrosine phosphorylation. METHODS: The hemorrhagic shock model [(35±5)mmHg] was established in rats and the whole lysate of superior mesenteric artery were extracted and analyzed by immune precipition (IP) and immunoblotting. The tyrosine phosphorylation levels of BK_Ca channel alpha-subunit in mesenteric artery in hemorrhagic shock rats were investigated, and the modulation of BK_Ca channel alpha-subunit tyrosine phosphorylation by NO and its dose-and time-dependended relationships were observed. RESULTS: The tyrosine phosphorylation level of BK_Ca channel alpha-subunit in mesenteric artery in rats increased significantly after hemorrhagic shock 2 h and 4 h (P<0.01 ), and L-arginine (5×10^-5-5×10^-4 mol/L) up-regulated BK_Ca channel alpha-subunit tyrosine phosphorylation in primary cultured VSMC in a 30 min incubation and without significant decrease after 2 h; L-arginine induced BK_Ca channel alpha-subunit tyrosine phosphorylation in a dose-dependent manner. CONCLUSION: Hemorrhagic shock enhances BK_Ca channel tyrosine phosphorylation in resistant artery in rats, and NO is involved in this process.     

Effects of Astragalus injection on neuronal apoptosis and expression of JNK3 in rat hippocampus after cerebral ischemia reperfusion

AIM:To investigate the effects of Astragalus injection on neuronal apoptosis and expression of c-Jun N-terminal kinase 3(JNK3) in the rat hippocampus after cerebral ischemia reperfusion. METHODS:The rat model of cerebral ischemia reperfusion was set up by a four-vessel occlusion method. The SD rats were randomly divided into 4 groups:sham operation group, cerebral ischemia reperfusion group(model group), cerebral ischemia reperfusion+Astragalus injection group(Astragalus injection group) and cerebral ischemia reperfusion+vehicle group(vehicle group). The rats in model group, Astragalus injection group and vehicle group after transient global cerebral ischemia(30 min) were then divided into 7 subgroups according to the reperfusion time of 0 h, 0.5 h, 2 h, 6 h, 24 h, 72 h and 120 h. The apoptosis of the neuron in the hippocampus was measured by the method of TUNEL staining. The expression of JNK3 at mRNA and protein levels was determined by real-time PCR and Western blotting,respectively. RESULTS:Compared with sham operation group, the number of apoptotic neurons increased in model group(P<0.05). Compared with model group, the number of apoptotic neurons decreased obviously in Astragalus injection group(P<0.05). Compared with sham operation group, the expression of JNK3 at mRNA and protein levels in the hippocampus increased obviously in model group at all time points except 120 h(P<0.05). Compared with model group, the expression of JNK3 at mRNA and protein levels in the hippocampus decreased obviously in Astragalus injection group at all time points except 120 h(P<0.05). CONCLUSION:Astragalus injection decreases neuronal apoptosis in rat hippocampus after cerebral ischemia reperfusion by inhibiting the expression of JNK3 at mRNA and protein levels.     

Effects of simulated ischemia/reperfusion on spontaneous action potentials in primary cultured sinoatrial node cells and the influence of pinacidil

AIM: To study the effects of ischemia/reperfusion (I/R) on primary cultured sinoatrial node (SAN) cells and the influence of pinacidil (a K_ATP channel activator). METHODS: The SAN cells were isolated from newborn rats and purified. The 48 h cultured cells were cultivated in following mediums: simulated reperfusion solution as normal control, simulated ischemia/reperfusion solution (I/R), Pinacidil+I/R (P+I/R), 5-HD+P+I/R and 5-HD+I/R. Spontaneous action potentials were recorded by ruptured-patch whole-cell technique in current clamp (I=0) and the maximum diastolic potential (MDP), upstroke velocity (UV), action potential overshoot (APO), interbeat interval (IBI) and action potential durations at 50% repolarization (APD₅₀) were measured. RESULTS: Compared with control group, simulated ischemia/reperfusion shorten APD₅₀, reduced UV, MDP and APO. Exposed to pinacidil, MDP of cells in I/R groups was hyperpolarized; IBI, UV and APO were increased; APD₅₀ was shorten. 5-HD couldn't block the effects of pinacdil on APD₅₀, IBI and MDP, but reversed its actions on increasing UV and APO. CONCLUSIONS: Pinacidil made changes of AP in I/R group by opening different K_ATP channels of SAN cells. The role of this changes on protection in SAN cells during ischemia/reperfusion requires further investigation.     

Effect of ischemic preconditioning on vascular reactivity and calcium sensitivity in hemorrhagic shock rats

AIM: To investigate the effect of ischemic preconditioning (IPC) on vascular reactivity and calcium sensitivity during hemorrhagic shock. METHODS: Appropriate method of IPC was selected by observing the effect of different strategies of IPC on the survival time and the survival rate in hemorrhagic shock rats. The effect of IPC on the pressor effect of norepinephrine (NE, 3 μg/kg) and the contractile response of superior mesenteric artery (SMA) to NE and calcium in vivo and in vitro were observed. RESULTS: Among 3 strategies of IPC, 3 cycles of abdominal aorta occlusion for 1 min and loosing for 5 min increased the survival time and 24 h survival rate significantly, which was superior to the other two IPC methods. In vivo, IPC significantly increased the pressor response to NE and the contractile response of SMA to NE (P<0.01). In vitro, IPC significantly improved the reactivity of SMA to NE and Ca²⁺. The E_max values of SMA to NE and Ca²⁺ in IPC group were significantly higher than that in shock control group (P<0.01). CONCLUSION: Ischemic preconditioning reverses Shock-induced vascular hyporeactivity via improving calcium sensitivity of the vasculatures.     

Effects of drynaria total flavonoids on serum levels of leptin,interleukin 6, prostaglandin E2 and expression of bone β2-adrenergic receptor in ovariectomized osteoporosis rats

AIM: To investigate the effects of drynaria total flavonoids on serum levels of leptin (LEP), interleukin 6(IL-6), prostaglandin E₂(PGE₂) and the expression of bone β₂-adrenergic receptor (ADRB2) in a rat model of ovariectomized osteoporosis(OP). METHODS: The osteoporosis model was established by ovariectomy. Twelve weeks after modeling,bone mineral density (BMD) was determined by dual-energy X-ray absorptiometry to verify successful modeling.Enzyme-linked immunosorbent assay was applied to detect the concentrations of LEP, IL-6 and PGE₂ in serum. The expression of ADRB2 was determined by immunohistochemical technique. RESULTS: Compared with sham group,BMD of the rats in model group significantly decreased in multiple regions 12 weeks after modeling(P<0.01). The serum levels of LEP, IL-6 and PGE₂ in model group were significantly higher than those in sham group(P<0.05). The levels of LEP, IL-6 and PGE₂ in drynaria total flavonoids group were significantly lower than those in model group(P<0.01). No significant difference of PGE₂ between these 2 groups was observed. The ADRB2 expression in sham group and treatment group was significantly different from that in model group, and no significant difference between sham group and treatment group was found. CONCLUSION: The serum levels of LEP, IL-6 and PGE₂ and the expression of bone ADRB2 increased in OP rats.Drynaria total flavonoids reduce the production of LEP, IL-6 and the expression of ADRB2, and suppress the bone absorption, which may be one of the mechanisms in treating OP.     

Effect of exogenous H2S and ATP-sensitive potassium channels on colonic hypermotility in a rat model of chronic stress

AIM: To investigate the potential role of exogenous hydrogen sulfide (H₂S) and ATP-sensitive potassium (K_ATP) channels in chronic stress-induced colonic hypermotility.METHODS: Male Wistar rats were divided into water avoidance stress (WAS) group and sham WAS (SWAS) group. Organ bath recordings were used to test the contractile activity of colonic strips. The effects of H₂S donor NaHS and pretreatment with glibenclamide on the contractions of colonic smooth muscle were studied and the IC₅₀ of NaHS was calculated. The localization and expression of the subunits of K_ATP channels were determined by the methods of immunohistochemistry and Western blotting.RESULTS: WAS increased contractile activity of colonic strips. NaHS concentration-dependently inhibited the spontaneous contractions of strips from the SWAS and WAS rats. The IC₅₀ of NaHS for longitudinal muscle (LM) and circular muscle (CM) of the WAS rats was 0.2033 mmol/L and 0.1438 mmol/L, significantly lower than those of the SWAS rats. Glibenclamide significantly increased the IC₅₀ of NaHS for LM and CM from the SWAS and WAS rats. In both SWAS and WAS rat colon, Kir6.1, Kir6.2 and SUR2B were expressed on the plasma membrane of the smooth muscle cells. WAS treatment resulted in up-regulation of the expression of Kir6.1 and SUR2B in the colon devoid of mucosa and submucosa.CONCLUSION: The increased expression of Kir 6.1 and SUR2B in colonic smooth muscle cells may be a defensive response to chronic WAS. H₂S donors may have potential clinical effect on treating chronic stress-induced colonic hypermotility.     

Blockage of mesenteric lymph return promotes the vascular reactivity and calcium sensitivity in hemorrhagic shock rats

AIM: To observe the effects of mesenteric lymph duct ligation and mesenteric lymph drainage on the vascular reactivity and calcium sensitivity in hemorrhagic shock (HS) rats, and to investigate the role of mesenteric lymph on the vascular hyporeactivity during shock. METHODS: Seventy-two male Wistar rats were randomly divided into sham group (only operation), shock (duplicating HS model) group, shock+ligation group (duplicating HS model and mesenteric lymph duct ligation) and shock+drainage group (duplicating HS model and mesenteric lymph drainage). The changes of mean artery pressure (MAP) after injection of norepinephrine (NE, 3 μg/kg) at different time points were recorded. After hypotension (40 mmHg) for 3 h, the vascular ring of superior mesenteric artery (SMA) was made for determining the vascular reactivity and sensitivity to calcium by observing the contraction initiated by NE and Ca²⁺ under depolarizing conditions (120 mmol/L K⁺) in the isolated organ perfusion system. Meanwhile, the effects of angiotensin Ⅱ (AngⅡ) and insulin (Ins) on the vascular reactivity were also observed. RESULTS: Compared to sham group, the △MAP in shock group was increased significantly at 0 h and 0.5 h after shock, and that was decreased markedly at 1.5 h, 2 h, 2.5 h and 3 h after shock, respectively, and that in shock+ligation group and shock+drainage group was increased at 0 h, 0.5 h and 1 h after shock, decreased at 2.5 h and 3 h after shock, respectively. The △MAP in shock+ligation group and shock+drainage group was higher than that in shock group at 0.5 h after shock and all the time points followed. The SMA reactivity to NE and sensibility to Ca²⁺ in shock group, shock+ligation group and shock+drainage group were lower markedly than those in sham group. The vascular reactivity and calcium sensitivity in shock+ligation and shock+drainage groups were higher than those in shock group. The vascular reactivity and calcium sensitivity in shock group, shock+ligation group and shock+drainage group were lower than those in sham group, and those in shock+ligation and shock+drainage groups were increased as compared to shock group, respectively. CONCLUSION: Blockage of mesenteric lymphatic return with the methods of mesenteric lymph duct ligation and mesenteric lymph drainage promotes the vascular reactivity of HS rats. The mechanism may be related to improving the calcium sensitivity in the vasculature.     

Riboflavin preconditioning alleviates hepatic ischemia/reperfusion injury in rats

AIM: To explore the protective effect of riboflavin preconditioning on hepatic ischemia/reperfusion injury in rats. METHODS: Twenty-four Sprague-Dawley rats wererandomly divided into 3 groups (n=8): sham group, ischemia/reperfusion (I/R) group and riboflavin preconditioning (R+I/R) group. The rats in sham group and I/R group received a standard chow,while the rats in R+I/R group received a chow supplemented with riboflavin. After 4 weeks, portal vein and hepatic artery supplying the middle and left hepatic lobes were clamped with a traumatic vascular clip for induction of partial hepatic ischemia in the rats in I/R group and R+I/R group. After 1 h of ischemia, 1 h of reperfusion was conducted by removal of the clip. The activity of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in serum,the activity of superoxide dismutase (SOD) and the level of malondialdehyde (MDA) in serum and liver were measured. Western blotting was employed to examine the protein expression of heme oxygenase-1(HO-1) in the liver. RESULTS: The results showed that ischemia/reperfusion injury markedly increased the activity of AST and ALT in serum, decreased the activity of SOD, and elevated the level of MDA and the activity of HO-1 in the liver as compared with sham group (P<0.01). The riboflavin pretreatment significantly decreased the activity of AST and ALT in serum, increased the activity of SOD and decreased the levels of MDA in serum and liver as compared with I/R group (P<0.01). In addition, the protein expression of HO-1 and the activity of HO-1 were elevated in R+I/R group (P<0.01). Cytoplasmic vacuolation and swelling of the hepatocytes were observed in I/R group. Treatment with riboflavin markedly alleviated the changes of liver structure. CONCLUSION: Riboflavin preconditioning has protective effect on hepatic ischemia/reperfusion injury. The mechanism may be correlated with enhancing the anti-oxidation and alleviating the reaction of lipid peroxidation.     

Influence of hydrogen sulfide on ileal epithelial cell apoptosis in rats with intestinal ischemia-reperfusion injury

AIM: To investigate the influence of hydrogen sulfide (H₂S) on intestinal epithelial cell mitochondrial morphology and function and the expression of caspase-3, cleaved caspase-3, cytochrome C (Cyt C), Bcl-2 and Bax in rats with intestinal ischemia-reperfusion (I/R) injury. METHODS: Wistar rats (n=24) were randomly divided into 3 groups (8 in each group): sham group, I/R group and I/R+sodium hydrosulfide (NaHS) group. The animal model of intestinal I/R injury was established. The rats in I/R+NaHS group received NaHS (100 μmol/kg bolus +1 mg·kg^-1·h^-1 infusion) 10 min prior to the onset of reperfusion, whereas the rats in I/R group and sham group received equal volume of normal sodium. Ileum epithelial mitochondrial morphology and function were measured. Plasma H₂S was detected by sensitive sulfide electrode. The expression of Bcl-2 and Bax mRNA was studied by RT-PCR. The protein levels of caspase-3, cleaved caspase-3, cytochrome C (Cyt C), Bcl-2 and Bax were tested by Western blot.RESULTS: The area, volume density, maximum diameter, minimum diameter and equivalent diameter of mitochondria, and the expression of cleaved caspase-3, Cyt C and Bax in I/R group were significantly higher than those in I/R+NaHS and sham groups (P<0.01). The mitochondrial count, circumference, specific surface area, area density and population density, plasma H₂S, respiratory control rate (RCR), the ratio of P/O, R₃ , R₄, and the expression of Bcl-2 in I/R group were sharply lower than those in I/R+NaHS and sham groups (P<0.01). H₂S was negatively correlated with caspase-3, cleaved caspase-3, Cyt C and Bax (P<0.01), and was positively correlated with Bcl-2 (P<0.01). CONCLUSION: H₂S has a protective effect on mitochondrial morphology and function in rats with intestinal I/R injury by down-regulating cleaved caspase-3, Cyt C and Bax and up-regulating Bcl-2.     

Effects of hypoxia and hypercapnia on expression of soluble guanylate cyclase in rat pulmonary artery

AIM:To investigate the expression of soluble guanylate cyclase protein and its mRNA in rat pulmonary artery after exposure to hypoxia and hypercapnia.METHODS:Male Sprague-Dawley rats were randomly split into 4 group, which were hypoxic hypercapnic (HH 1 week, HH 2 weeks, HH 4 weeks) group and control group, to copy pulmonary hypertensive animal model. The expression of sGCα₁ and β₁ subunits protein of medial and small pulmonary artery was performed by immunohistochemistry with a polycolonal antibody. In situ hybridization was performed on the rat lung tissue using sGC oligonuclear probe to assay the expression of sGCα₁subunit mRNA.RESULTS:The sGCα₁ and β₁ subunits protein and sGCα₁ subunit mRNA were faint staining in the pulmonary small and medium artery in HH1 week, HH 2 weeks and HH 4 weeks groups compared with control group (all P＜0.01).CONCLUSION:sGC subunit mRNA and protein expression in pulmonary small and medium artery were decreased after exposure to hypoxia and hypercapnia, which took part in the development of the pulmonary hypertension.