Role of post-hemorrhagic shock mesenteric lymph in enhancement of vascular permeability

AIM：To investigate the role of post-hemorrhagic shock mesenteric lymph (PHSML) in the enhancement of vascular permeability. METHODS：Eighteen Wistar rats were randomized into sham group, shock group, and shock plus mesenteric lymph drainage (shock + drainage) group. The rats in shock group and shock + drainage group were routinely subjected to hemorrhagic shock and hypotension ［(40±2） mmHg］ was maintained for 90 min, and then the fluid resuscitation was performed. Mesenteric lymph was drained in the rats in shock+drainage group from resuscitation finished to 6 h, for the observation of PHSML drainage on the vascular permeability in multiple tissues of hemorrhagic shock rats. Afterwards, human umbilical vein endothelial cells (HUVECs) were incubated with the PHSML in vitro to observe the effects of PHSML on the morphology and permeability of HUVECs. RESULTS：The degree of blue color and concentrations of Evens blue in the lung, myocardium, kidney, liver, spleen and small intestine were significantly increased in the shocked rats than that in sham group, while the ratios of the dry weight to the wet weight were decreased. The mesenteric lymph drainage reversed these changes. Meanwhile, 4% and 10% of PHSML at 0~3 h and 3~6 h after resuscitation, and lipopolysaccharide (10 mg/L) all caused the damage of HUVECs, decreased the viability and trans-endothelial electrical resistance of HUVECs, and increased the permeability of HUVECs to fluorescein isothiocyanate-labeled albumin. CONCLUSION：PHSML is a vital factor in the enhancement of vascular permeability.     

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.     

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.     

Mesenteric lymph drainage alleviates spleen injury in hemorrhagic shock rats

AIM：To observe the effects of post-shock mesenteric lymph (PSML) drainage on histopathology, apoptosis, cell cycle and proliferation of the spleen in rats with hemorrhagic shock. METHODS：Eighteen Wistar rats were randomly divided into sham, shock and shock+drainage groups (n=6 in each group). The hemorrhagic shock model was established in the shock and shock+drainage groups. Fluid resuscitation for 30 min was performed 1.5 h after hypotension, and PSML was drained in the rats in shock+drainage group from 1 h after hypotension to 3 h after resuscitation finished. The fixed spleen tissue was harvested from each rat for histological observation with HE staining. The apoptosis of splenocytes was observed by Hoechst 33258 staining. The expression of Bcl-2 and Bax proteins was detected by immunohistochemical staining. The cell cycle and the expression of p53 protein were measured by flow cytometry, and the proliferation index (PI) was calculated. RESULTS：Compared with sham group, splenic tissue injury appeared in the shocked rats. The apoptotic cells and the expression of Bax and p53 in shock group were increased, while Bcl-2 expression was decreased. The percentage of G2/M cells in shock group was decreased. Compared with shock group, the splenic tissue damage in shock+drainage group was significantly attenuated. Moreover, the number of apoptotic cells, the percentage of G0/G1 cells, and the expression of Bax and p53 were obviously decreased, and the G2/M cells, Bcl-2 protein expression and PI were significantly increased in shock+drainage group. CONCLUSION: PSML drainage alleviates splenic injury in hemorrhagic shock rats, which may be related to reducing the apoptosis of splenocytes.     

Effects of hydrogen sulfide on high glucose-induced injury of mouse glomerular podocytes

AIM: To investigate the effect of hydrogen sulfide (H2S) on high glucose （HG）-induced injury of the mouse podocyte cell line MPC5. METHODS: The cultured MPC5 cells were randomly divided into 4 groups: HG group, normal glucose (NG) group, NG+DL-propargylglycine (PPG) group, and HG+NaHS group. After treated for a certain time, the cells were collected for further detection. The expression of zonula occludens-2 (ZO-2), nephrin, β-catenin and cystathionine γ-lyase (CSE) was determined by Western blotting. RESULTS: High glucose significantly reduced the expression of nephrin, ZO-2 and CSE (P<0.05), while the level of β-catenin was elevated obviously (P<0.05), all in a time-dependent manner. NG+PPG inhibited the levels of ZO-2 and nephrin significantly (P<0.05), and increased the level of β-catenin (P<0.05), all in a PPG concentration-dependent manner. HG+NaHS induced a more significant increase in the levels of ZO-2 and nephrin as compared with HG group (P<0.01), whereas a severe reduction of β-catenin in HG+NaHS group was observed as compared with HG group. Compared with NG group, the expression of ZO-2 and nephrin was decreased obviously, and the level of β-catenin was increased in HG+NaHS group. CONCLUSION: Down-regulation of CSE contributes to hyperglycemia-induced podocyte injury. Exogenous H2S protects against hyperglycemia-induced podocyte injury, possibly through up-regulation of ZO-2 and subsequent suppression of Wnt/β-catenin pathway.     

Hydrogen sulfide inhibits inflammatory responses induced by acute myocardial ischemia in isolated rat hearts

AIM：To investigate whether hydrogen sulfide (H2S) protects the hearts against inflammatory responses induced by acute myocardial ischemia in isolated rat hearts. METHODS：Rat acute myocardial ischemia injury was induced by ligation of the left anterior descending coronary artery for 4 h, and the normal perfusate was replaced with NaHS (5 μmol/L, 10 μmol/L and 20 μmol/L) perfusate accordingly in NaHS groups 2 h after ischemia. The changes of cardiac function in the myocardial ischemic injury rats were observed. The mRNA expression of TNF-α, IL-1β, IL-6, IL-10 and ICAM-1 was detected by real-time PCR. The protein level of nuclear factor-κB (NF-κB) in the myocardial tissues was detected by Western blotting. RESULTS：The cardiac function in ischemia group was lower than that in sham group (P<0.01). Compared with ischemia group, perfusion of NaHS resulted in the improvement of the cardiac function (P<0.05 or P<0.01). Compared with sham group, the mRNA expression of TNF-α, IL-1β, IL-6 and ICAM-1 in the cardiac tissues was significantly increased, and the mRNA expression of IL-10 in the cardiac tissues was significantly decreased in ischemia group (P<0.01). Compared with ischemia group, the perfusion of NaHS significantly decreased the mRNA expression of TNF-α, IL-1β, IL-6 and ICAM-1 (P<0.05 or P<0.01). The perfusion of NaHS at concentrations of 10 μmol/L and 20 μmol/L significantly increased the mRNA expression of IL-10 (P<0.01). The protein level of NF-κB in ischemia group was markedly higher than that in sham group (P<0.01). Compared with ischemia group, the perfusion of NaHS at concentrations of 10 μmol/L and 20 μmol/L significantly decreased the expression of NF-κB (P<0.05 or P<0.01). CONCLUSION：H2S protects the hearts against acute ischemia injury through inhibition of NF-κB activation and subsequent down-regulation of NF-κB-dependent inflammatory gene expression.     

Endogenous hydrogen sulfide regulates oxidant/antioxidant balance in rat with chronic obstructive pulmonary disease

AIM: To investigate the role of hydrogen sulfide (H₂S) in the protection against oxidative stress in rats with chronic obstructive pulmonary disease (COPD).METHODS: The rat model of COPD was established by cigarette smoking (CS) combined with lipopolysaccharide (LPS) instillation. Thirty-two healthy male Sprague-Dawley rats were randomly divided into 4 groups: control group, CS+LPS group, CS+LPS+NaHS (H₂S donor) group and CS+LPS+PPG (DL-propargylglycine, an inhibitor of cystathionine-γ-lyase) group. After 30 days, the lung functions of the rats were measured, the histological changes of lungs were observed under light microscope and the pathological scores were calculated. The H₂S level in plasma and the protein expression of cystathionine-γ-lyase (CSE) in the lung tissues were measured. The content of malondialdehyde (MDA), the activity of superoxide dismutase (SOD) and catalase (CAT) were detected to reflect oxidative stress.RESULTS: Compared with control group, the peak expiratory flow (PEF) decreased by 24% and intra-pressure (IP) increased by 66% in CS+LPS group. The pathological scores of the lung tissues also increased. Compared with CS+LPS group, no change in the lung function was observed after given NaHS or PPG, but the pathological scores decreased in CS+ LPS+ NaHS group. Compared with control group, the content of H₂S in plasma was increased by 26% on day 16. Compared with CS+LPS group, the content of H₂S in plasma of CS+LPS+PPG group was decreased by 22% after 30 days. Compared with control group, the protein expression of CSE increased, and no statistical difference among CS+LPS group, CS+ LPS+ NaHS group and CS+LPS+PPG group was observed. Compared with control group, MDA content in the lung tissues was increased by 24% in CS+LPS group, the activity of SOD was increased by 47% and the activity of CAT was increased by 52%. Compared with CS+LPS group, the MDA content in CS+LPS+NaHS group was decreased by 21%, and no statistical difference in the activity of SOD and CAT was observed. The activity of SOD decreased by 33% after given PPG.CONCLUSION: H₂S plays a role as anti-oxidant in the rats with COPD. The CSE/ H₂S pathway may be involved in the development of COPD.     

Protective role of endogenous hydrogen sulfide in cholecystokinin octapeptid against acute lung injury induced by lipopolysaccharide

AIM: To explore the role of endogenous hydrogen sulfide (H₂S) in the mechanism of cholecystokinin octapeptide (CCK-8) to alleviate acute lung injury (ALI) induced by lipopolysaccharide (LPS). METHODS: Eighty-four Sprague-Dawley rats were randomly divided into seven groups: control, LPS (instilled intratracheally to reproduce the model of ALI), NaHS (H₂S donor) +LPS, propargylglycine ［inhibitor of cysathionine-γ-lyase (CSE), PPG］+LPS, CCK-8+LPS, PPG+CCK-8+LPS and CCK-8 group. Animals were sacrificed at 4 h and 8 h after agent instillation. The wet and dry ratio (W/D) of the lung weight was measured and calculated. Morphological changes of lung tissues were observed. H₂S concentration in plasma, malondialdehyde (MDA) content, myeloperoxidase (MPO) and CSE activities in the lung were determined. Furthermore, the level of P-selectin of lung tissue was measured by radioimmunoassay, the CSE mRNA expression in the lung was detected by RT-PCR, and the protein content in bronchoalveolar lavage fluid (BALF) was detected. RESULTS: Compared with control, severe injury of lung tissues and increase in W/D, protein content in BALF, MDA content, MPO activity and P-selectin level in the lung were observed in rats treated with LPS. LPS also lead to a drop in plasma H₂S concentration, lung CSE activity and CSE mRNA expression. Administration of NaHS before LPS could attenuate the changes induced by LPS, while H₂S concentration, CSE activity and CSE mRNA expression were higher than those in LPS group. However, pre-treatment with PPG exacerbated the lung injury induced by LPS, H₂S concentration, CSE activity and CSE mRNA expression were lower than those in LPS and CCK-8 +LPS group, respectively. CONCLUSION: CCK-8 attenuates LPS-induced acute lung injury by means of anti-oxidation and inhibition of PMN adhesion and aggregation, both of which are mediated by endogenous H₂S.     

Impact of hydrogen sulfide donor on endothelin-1 and connective tissue growth factor expression in rats with pulmonary hypertension induced by high pulmonary blood flow

AIM: To explore the possible impact of hydrogen sulfide (H2S) donor-sodium hydrosulfide (NaHS) on endothelin-1 (ET-1) and connective tissue growth factor (CTGF) expressions in rats with pulmonary hypertension induced by high pulmonary blood flow. METHODS: Thirty-two male SD rats were randomly divided into 4 groups: shunt group, shunt+NaHS group, sham group and sham+NaHS group. Rats in shunt group and shunt+NaHS group were subjected to an abdominal aorta-inferior vena cava shunt to create an animal model of high pulmonary flow. After 11 weeks of experiment, rat systolic pulmonary artery pressure (SPAP), lung tissue H2S, plasma ET-1 concentration and lung tissue ET-1mRNA expression, as well as pulmonary artery CTGF protein expression were detected.RESULTS: After 11 weeks of experiment, SPAP, lung tissue ET-1mRNA, plasma ET-1 as well as pulmonary artery CTGF expressions were increased markedly, respectively, whereas H2S in lung tissue decreased significantly in rats of shunt group as compared with that in sham group (all P<0.05). After administration of NaHS for 11 weeks, H2S in lung tissue increased significantly, whereas SPAP, plasma ET-1 and lung tissue ET-1 mRNA expression as well as pulmonary artery CTGF protein expression decreased significantly, respectively, in rats of shunt+NaHS group as compared with that in shunt group (all P<0.05).CONCLUSION: NaHS might be involved in the development of pulmonary hypertension induced by high pulmonary blood flow by down-regulating vasoactive peptides ET-1 and CTGF expressions in lung tissues of rats.     

Isolation of exosomes and effect of stellate ganglion block on the number of exosomes in post-hemorrhagic shock mesenteric lymph of rats

AIM To isolate the exosomes in mesenteric lymph, verify the source of exosomes, and observe the effect of stellate ganglion block （SGB） on the number of exosomes in post-hemorrhagic shock mesenteric lymph （PHSML） of rats. METHODS Twenty-four male rats were randomly divided into sham, sham+SGB, shock, and shock+SGB groups. SGB was performed before the establishment of hemorrhagic shock model using the routine methods in our lab. The PHSML was drained for exosomes isolation. The exosomes were identified through particle size analysis and CD63 protein expression. The expression of epithelial cell adhesion molecule （EpCAM） was detected to identify whether the exosomes were derived from epithelial cell. The number of exosomes in various mesenteric lymphs was measured using the flow cytometry. RESULTS The diameter of granular material extracted from mesenteric lymph was about 100 nm. The positive expression of exosomes pecific protein CD63 indicated the successful isolation of exosomes, and the EpCAM expression verified the exosomes were derived from intestinal epithelial cells. The number of exosomes in mesenteric lymph isolated from the rats of Shock group was obviously increased compared to that from the Sham group （P<0.05）, while the exosomes from the Shock+SGB group was markedly decreased when compared to Shock group （P<0.05）. CONCLUSION The current study establishes the isolation technique of exosomes in mesenteric lymph, and proved the exosomes were derived from the intestinal epithelial cells. SGB treatment reduces the number of exosomes in PHSML.     

Hydrogen sulfide attenuates urosepsis-induced acute kidney injury by blocking TLR4/MyD88/PI3K signaling pathway

AIM:To explore the effect of hydrogen sulfide (H₂S) on urosepsis-induced acute kidney injury. METHODS:New Zealand white rabbits were randomly divided into control group, sham group, model (sepsis) group, NaHS treatment (NaHS) group, and NaHS combined with TAK-242 (a TLR4 inhibitor) treatment (NaHS+TAK-242) group. After treatment for 72 h, HE staining was used to measure the histopathological changes of rabbit kidney. The levels of blood urea nitrogen (BUN) and serum creatinine (SCr) were detected by automatic biochemical analyzer. The serum levels of neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule 1 (KIM-1), procalcitonin (PCT), interleukin-1β (IL-1β), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were measured by ELISA. The TLR4/MyD88/PI3K signaling pathway-related proteins in the kidney were determined by Western blot. RESULTS:Compared with control group, obvious damage was observed in the kidneys of septic rabbits, but the kidneys were markedly improved by treatment with NaHS. The levels of BUN, SCr, NGAL, KIM-1, PCT, IL-1β, IL-6 and TNF-α in the septic rabbits were higher than those in control group, and decreased significantly in NaHS group and NaHS+TAK-242 group. The protein levels of TLR4, MyD88, p-PI3K and p-Akt in septic rabbit kidneys were higher than those in control group. However, NaHS or NaHS+TAK-242 inhibited the activation of TLR4/MyD88/PI3K signaling pathway in the kidneys of septic rabbits. CONCLUSION:H₂S play a protective effect on the rabbits with urosepsis-induced acute kidney injury by blocking TLR4/MyD88/PI3K signaling pathway to inhibit inflammatory response.     

Estrogen treatment enhances mesenteric lymphatic contractility in rats after hemorrhagic shock

AIM To investigate the effects of 17β-estradiol （E2） treatment on the mesenteric lymphatic microcirculation and isolated lymphatic contractility in rats after hemorrhagic shock, and to explore the relationship between contractility and the difference between intra- and extracellular calcium ion concentrations （［Ca²⁺］） of lymphatic smooth muscle cells （LSMCs）. METHODS Male Wistar rats were divided into sham group, shock group and shock+E2 group. The rats were subjected to hemorrhage ［（40±2） mmHg for 90 min］ and resuscitation with or without subcutaneous injection of E2 （2 mg/kg）. After resuscitation for 3 h, the mesenteric lymphatic microcirculation in vivo was observed. Moreover, the isolated mesenteric microlymphatic rings were prepared for the observations of lymphatic contractility evaluated by the indexes including end-systolic diameter, end-diastolic diameter, contraction frequency （CF） and passive diameter. Meanwhile, the difference between intra- and extracellular ［Ca²⁺］ of LSMCs was recorded during lymphatic contraction. RESULTS Treatment with E2 significantly enhanced the CF, total contractile fraction and lymphatic dynamics index in vivo in the rats after hemorrhagic shock, and increased the CF, the fractional pump flow and the difference between intra- and extracellular ［Ca²⁺］ of LSMCs in isolated lymphatics from the shocked rats （P<0.05）. CONCLUSION Estrogen treatment enhances lymphatic contractility in rats after hemorrhagic shock, which is related to enhancement of difference between intra- and extracellular ［Ca²⁺］ of LSMCs.     

Effect of mesenteric lymph reperfusion on multiple organs injury in superior mesenteric artery occlusion shock rats

AIM: To explore the effect of mesenteric lymph reperfusion (MLR) on blood pressure, survival rate and organ injury in superior mesenteric artery occlusion (SMAO) shock rats.METHODS: Male Wistar rats were randomly divided into 4 groups: in sham group, only anesthetized and operation; in MLR group, performed 1 h occlusion of mesenteric lymphatics (ML) followed by 2 h of reperfusion; in SMAO group, performed 1 h occlusion of superior mesenteric artery (SMA) followed by 2 h of reperfusion; in MLR+SMAO group, performed 1 h occlusion of SMA and ML followed by 2 h of reperfusion. Histopathological and function changes of the lung, liver, kidney and myocardium in rats were assessed after 3 h of mean arterial pressure (MAP) was observed continuously in rats. The survival rate of 24 h was recorded.RESULTS: ① The 24 h survival rates of rats in sham, MLR, SMAO group (100%, 83.3%, 66.7%, respectively) were significant higher than those in MLR+SMAO group (0%). ② The changes of MAP in 4 groups were not statistically different before occlusion. The MAP in SMAO group was higher than that in MLR+SMAO and sham groups at multi-time points after clamping. After reperfusion, the change of MAP in MLR and sham groups was not obvious, and the MAP in SMAO group at multi-time points was decreased than that in MLR and sham groups. MAP in MLR+SMAO group was decreased compared with SMAO, MLR, sham group at all time points after reperfusion. ③ The levels of AST, ALT, BUN, Cre, LDH-1 and CK-MB in MLR+SMAO group in serum were higher than those in sham, MLR and SMAO groups, and these indexes in SMAO group were higher than those in sham and MLR groups. The morphologic observation showed that the structures in kidney, lung, liver and myocardium were normal in sham and MLR groups, however, inflammation, hemorrhage, congestion and necrosis were found in MLR+SMAO group, but only mild histopathological injury was found in SMAO group.CONCLUSION: Our data suggest that the MLR aggravates the multiple organs injury in SMAO shock, therefore, intestinal lymph pathway may play an important role in the pathogenesis of SMAO shock.     

Mechanism of mesenteric lymph duct ligation against the renal insufficiency in hemorrhagic shock rats

AIM: To observe the effect of mesenteric lymph duct ligation on free radical and inflammatory mediator in serious hemorrhagic shock rats at different periods, and explore the mechanism of intestinal lymphatic pathway on renal insufficiency. METHODS: 78 male Wistar rats were divided into the sham group, shock group, and ligation group. The model of serious hemorrhagic shock was established in shock group, ligation group, and mesenteric lymph was blocked by ligating mesenteric lymph duct in ligation group after resuscitating. All rats were executed and kidneys were taken out for making homogenate of 10 percent to determine levels of MDA, SOD, NO, NOS, tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and myeloperoxidase (MPO) at time points after shock 90 min, after transfusion and resuscitate 0 h, 1 h, 3 h, 6 h, 12 h and 24 h. The expression of inducible nitric oxide synthase (iNOS) mRNA in kindey was detected by RT-PCR. RESULTS: The contents of MDA, NO, NOS, TNF-α, IL-6, MPO and iNOS expressions in renal homogenate of shock group were increased after transfusion and resuscitation, and were higher at 6 h and 12 h, and was significantly higher than that in sham group. The acvitity of SOD was significantly lower than that in sham group (P<0.01, P<0.05). The contents of MDA, NO, NOS, TNF-α, IL-6, MPO and iNOS expression in renal homogenate of ligation group after transfusion and resuscitation 6 h, 12 h and 24 h were significantly lower than those in shock group at same points, and the SOD activity was higher (P<0.01, P<0.05). CONCLUSION: The results demonstrate that the ligation of mesenteric lymph duct can antagonise the development of renal failure in serious hemorrhagic shock rats, and its mechanism might relate to reduce the PMN sequestration, decrease the levels of TNF-α and IL-6, inhibit NO production and expression of iNOS mRNA, suppress the release of free radical and consumption of SOD.     

Mechanism of mesenteric lymph reperfusion aggravates multiple organ injury in superior mesenteric artery occlusion shock rats

AIM: To explore the mechanism of mesenteric lymph reperfusion (MLR) aggravates multiple organ injury in superior mesenteric artery occlusion (SMAO) shock rats. METHODS: Male Wistar rats were randomly divided into 4 groups: in sham group, only anesthetization and operation were performed; in MLR group, occlusion of mesenteric lymphatics (ML) for 1 h followed by 2 h of reperfusion; in SMAO group, occlusion of superior mesenteric artery (SMA) for 1 h followed by 2 h reperfusion; in MLR+SMAO group, occlusion of SMA and ML for 1 h followed by 2 h of reperfusion. The homogenates of liver, kidney, myocardium and lung were prepared for determining the activities of free radical, nitric oxide, myeloperoxidase (MPO) and cell membrane ATPase. RESULTS: The MDA, NO contents and NOS, MPO activities of multiple organic homogenate in SMAO and MLR+SMAO group were higher than those in sham and MLR group, and these indexes in MLR+SMAO were increased significantly than those in SMAO group. The SOD and ATPase activities of muliple organic homogenate in SMAO and MLR+SMAO group were lower than those in sham and MLR group, and those in MLR+SMAO group was decreased obviously than those in SMAO group. CONCLUSION: The MLR enhances the multiple organ free radical injury, NO synthesis and release, PMN detention and decreases the activity of cell membrane ATPase, aggravating the major organs injury in SMAO shock rats. Intestinal lymphatic pathway plays an important role in the pathogenesis of SMAO shock.     

Role of post-hemorrhagic shock mesenteric lymph drainage in restoring balance of ACE/ACE2 in kidney of mice

AIM: To study the role of post-hemorrhagic shock mesenteric lymph (PHSML) drainage on the balance of angiotensin-converting enzyme (ACE) and ACE2 in the kidney. METHODS: A hemorrhagic shock model was established and then fluid resuscitation was performed to the animals in shock and shock+drainage groups, and the PHMSL was drained in shock+drainage group after fluid resuscitation. After 6 h of resuscitation, the mRNA expression of ACE, ACE2, angiotensin Ⅱ (Ang Ⅱ) type 1 receptor (AT1R) and Mas-related G-protein-coupled receptor (MasR), and the levels of Ang Ⅱ and Ang (1-7) in the renal tissues were observed. RESULTS: Hemorrhagic shock increased the levels of ACE mRNA, AT1R mRNA and Ang Ⅱ, and decreased the levels of ACE2 mRNA, MasR mRNA and Ang(1-7) in the kidney. PHSML drainage abolished the effect of hemorrhagic shock on ACE2 and AT1R mRNA expression. Meanwhile, PHSML drainage reduced the hemorrhagic shock-induced increases in the ratios of ACE/ACE2, Ang Ⅱ/Ang(1-7) and AT1R/MasR. CONCLUSION: The PHSML drainage restores the balance of ACE/ACE2, which is beneficial to alleviate acute kidney injury following hemorrhagic shock in the mice.     

Effect of endogenous H2S on pulmonary hypertension during acute lung injury induced by LPS and its interaction with NO

AIM: To investigate the effect of H2S on pulmonary artery hypertension during acute lung injury induced by LPS and the interaction between the systems of hydrogen sulfide (H2S)/cystathionine-β-lyase (CSE) and nitric oxide (NO)/nitric oxide synthase (NOS) in this process. METHODS: Seventy-two adult male rats were randomly divided into four groups: control group, LPS group, LPS+L-NAME group and LPS+propargylglycine (PPG) group. Mean pulmonary artery pressure (mPAP) of each rat was examined at 2 h, 4 h, 6 h and 8 h after treatment. H2S and NO contents in plasma, NO content, iNOS, cNOS and CSE activity in lung were measured at 4 h or 8 h after treatment, respectively. Expression of iNOS in lung tissue was also detected by immunohistochemistry technique, and the injury of lung was evaluated with morphological changes under microscope. RESULTS: LPS could induce severe lung injury, and mPAP, NO content, iNOS activity and its protein expression in LPS group significantly increased, but cNOS activity, H2S content and CSE activity decreased compared with those of control group. Administration of L-NAME before LPS could attenuate the changes induced by LPS. Pre-administration of PPG, a CSE inhibitor, exacerbated the injury by LPS, but there was no prominent variation in cNOS activity. CONCLUSION: Reduced endogenous H2S could increase pulmonary artery hypertension during acute lung injury induced by LPS. There is a negative effect between H2S/CSE system and NO/NOS system in this process.     

Role and mechanism of endothelial hydrogen sulfide in anti-atherosclerosis effect of estrogen

AIM：To investigate possible role and mechanism of endothelial hydrogen sulfide (H2S) in the anti-atherosclerosis effect of estrogen. METHODS：For in vitro experiment, cultured human umbilical vein endothelial cells (HUVECs) were treated with 17β-estradiol (E2), estrogen receptor α (ERα) agonist propylpyrazole triol (PPT), estrogen receptor β (ERβ) agonist diarylpropionitrile (DPN) and estrogen receptor antagonist ICI 182780 (ICI) for 5 min, and then the concentration of H2S in cell culture supernatants was detected by sensitive sulphur electrode assay. For in vivo experiment, high-fat diet-fed and ovariectomized (OVX) female ApoE–/– C57BL/6 mice were randomly divided into 3 groups and treated with placebo (OVX group), E2 (OVX+E2 group) and E2 plus cystathionine γ-lyase (CSE) inhibitor DL-propargylglycine (PPG) (OVX+E2+PPG group), respectively, and the blood concentration of H2S and the atherosclerotic plaque size were detected 8 weeks later. RESULTS：E2 significantly enhanced the release of H2S from HUVECs in a concentration-and time-dependant manner which could be blocked by the administration of ICI. Meanwhile, ERα agonist PPT, not ERβ agonist DPN, demonstrated similar effects to E2. Compared with OVX group, the atherosclerosis in mice was attenuated and the blood concentration of H2S was elevated in OVX+E2 group, while no significant changes were detected in OVX+E2+PPG group. CONCLUSION: Endothelial H2S can be rapidly released when membrane ERα is activated by estrogen, which plays a very important role in the anti-atherosclerosis effect of estrogen.     

Changes of hydrogen sulfide content in plasma and tissues of rats with LPS-induced shock

AIM: To investigate the changes and significance of hydrogen sulfide (H2S) in both plasma and various tissues, including liver, kidney, heart, lung and arteriae aorta, in rats with LPS-induced shock. METHODS: A rat model of shock induced by injection of lipopolysaccharide (LPS) was developed. Male Wistar rats were divided into four groups: control group, LPS group, LPS+NaHS (H2S donor) group and LPS+ propargylglycine (PPG, metabolic enzyme inhibitor of H2S) group. The mean arterial pressure (MAP) of rats within 240 min was observed，and H2S contents were determined. The structures of various tissues were observed. RESULTS: Administration of LPS to male Wistar rats caused a sustained fall in MAP, various tissue injuries and a significant increase in H2S contents in plasma as well as liver, kidney, heart, lung and arteriae aorta within 240 min（all P<0.05）. Treatment with metabolic enzyme inhibitor of H2S, propargylglycine, was shown to reduce H2S content elevation in plasma as well as liver, kidney, heart, lung, and arteriae aorta, and ameliorate the hypotension and tissue injuries caused by LPS（all P<0.05）. However, treatment with H2S donor-NaHS was shown to increase H2S content elevation in plasma as well as liver, kidney, heart, lung and arteriae aorta, and aggravate the hypotension and tissue injuries caused by LPS（all P<0.05）. Endogenous H2S contents in both plasma and various tissues were negatively correlated with MAP（all P<0.05）.CONCLUSION: H2S may be a new endogenous mediator and play a role in the pathogenesis of endotoxic shock.