Oxygen free radical injury of myocardial mitochondria in the experimental type 2 diabetic rats

AIM: To study the mechanism of diabetic cardiomyopathy and abnormality of oxygen free radicals. METHODS: The contents of myocardial cytosolic cytochrome C, mitochondria cytochrome C, mitochondrial calcium, NO, MDA and the activity of SOD and NOS were determined in diabetic rats induced by STZ. The pathological changes were observed under transmission electron microscope. RESULTS: Compared to the normal and ganoderma group, the levels of mitochondrial NO, iNOS, MDA, calcium and plasma Cyt-C in rat myocardium were higher (P<0.05), while mitochondrial Cyt-C and SOD were lowered in model group (P<0.05). The bouncary indistinct, disorganization, a focal loss of muscular fibril, myocardium mitochondria swelling, pulmonary vascular endothelial cellular swelling and obstructed lumen of the capillary were also observed under transmission electronic microscope. CONCLUSION: The findings indicate that oxyradical and lipid peroxidation might be associated with the damage of myocardial mitochondria in NIDDM rats. Cyt-C and mitochondrial calcium is also involved in the process.     

Tetramethylpyrazine combined with aminoguanidine improves hepatic functions in n0-STZ Wistar rats

AIM：To investigate the effects of tetramethylpyrazine combined with aminoguanidine on hepatic functions and expression of apoptosis-related proteins in neonatal-0 streptozocin (STZ)-induced (n0-STZ) diabetic rats. METHODS：Neonatal Wistar rats were intraperitoneally injected with a single dose of STZ to establish n0-STZ rat model．The n0-STZ rats were divided into 4 groups：normal control group, model group, metformin treatment group and tetrame-thylpyrazine+aminoguanidine treatment group (combined therapy group)．Fasting plasma glucose (FPG), fasting insulin (FINS), insulin resistance index (IRI), serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were measured at the 32nd week. Nitric oxide (NO) concentration, inducible nitric oxide synthase (iNOS) activity, and protein expression levels of iNOS, caspase-3, Fas and Bcl-2 in hepatic tissues were also analyzed．RESULTS： Treatment with metformin or combined therapy not only attenuated the increases in IRI and FPG, but also decreased the elevated serum levels of ALT and AST. Both treatments reduced NO concentration, iNOS,caspase-3 and Fas activity, and the protein expression of iNOS in the rat livers as well. The effects of combined therapy on the above indexes were stronger than those of metformin treatment. Both treatments enhanced the expression of Bcl-2 in the rat livers, and both effects had no difference. CONCLUSION：Tetramethylpyrazine combined with aminoguanidine improves hepatic functions by ameliorating impaired Bcl-2 expression and decreasing the expression levels of caspase-3 and Fas in the livers of n0-STZ rats, which has stronger efficacy than metformin.     

Role of endogenous nitric oxide synthase inhibitor in erectile dysfunction of diabetic rats

AIM: To investigate the role of nitric oxide synthase (NOS) inhibitor asymmetric dimethylarginine (ADMA) in erectile dysfunction of diabetic rats.METHODS: Type 2 diabetic rat model was established by 4 weeks of high-fat diet plus a single intraperitoneal injection of streptozotocin and continued high-fat diet feeding for 8 weeks. Corpus cavernosum was isolated from the rats under anesthetization, and the endothelium-dependent relaxation response to acetylcholine (ACh) was tested in an organ chamber to reflect erectile function. The level of ADMA in serum was detected. The NOS activity, nitric oxide (NO) content and cyclic guanosine monophosphate (cGMP) content in corpus cavernosum were measured. The protein expression of ADMA-NOS-NO pathway-related molecules and phosphodiesteras 5 (PDE5) in the corpus cavernosum was detected by Western blot. Superoxide dismutase activity and malondialdehyde content were analyzed to evaluate oxidative stress.RESULTS: Elevated blood glucose and lowered insulin sensitivity were observed in the diabe-tic rats, indicating that type 2 diabetic rat model was successfully established. Compared with control group, the relaxation response to ACh of corpus cavernosum from diabetic rats was significantly decreased, which was accompanied with the elevation of serum ADMA level and reduction of NOS activity, NO content and cGMP content in the corpus cavernosum. The protein expression of ADMA-generating enzyme protein arginine methyltransferase 1 was up-regulated, while ADMA-metabolic enzymes dimethylarginine dimethylaminohydrolases 1 and 2, and ADMA-targeting enzymes endothelial NOS and neuronal NOS were down-regulated. The protein expression of PDE5 was up-regulated, accompanied with an increase in oxidative stress in the corpus cavernosum of diabetic rats. Incubation of isolated corpus cavernosum from normal rats with NOS inhibitor ADMA induced the similar relaxation dysfunction of corpus cavernosum response to ACh and decreased NO and cGMP contents in diabetic rats.CONCLUSION: Elevated endogenous NOS inhibitor ADMA plays an important role in erectile dysfunction of diabetic rats. The underlying mechanism may be related to the reduction of NO production and the increase in oxidative stress.     

Changes in L-arginine/nitric oxide pathway of the aorta in septic shock rats

AIM:To observe the change of nitric oxide (NO) generation system in the vascular adventitia, media and intima in septic shock rats.METHODS:The septic shock model was made in rats by caecal ligation and puncture. The intima, media and adventitia of the rat aorta were separated. NO production (NO₂^-), nitric oxide synthase(NOS) activity and L-arginine (L-Arg) transport were measured, separately. Inducible NOS (iNOS) distribution was detected by immunohistochemistry.RESULTS:Both in early and late stage of septic shock, NO₂^- from the intima was decreased by 66.1% and 78.9%(P<0.01), while NO₂^- from the media was increased by 1.1 and 2.2 folds(P＜0.01), and the adventitia 9.6 and 18.6-fold (P＜0.01), as compared with the sham group, respectively. The changes of NOS activity and the L-arginine transport in the intima, the media layer and the adventitia of the aorta in the septic shock rat paralleled with that of NO₂^- in these tissues. The results of iNOS immunohistochemistry showed that there were obviously positive staining in the media layer and adventitia, especially the adventitia of the rat aortas in septic shock, as compared with that in the sham control.CONCLUSIONS:During septic shock, NO production in the aortic intima was progressively suppressed. However, it was progressively increased in the aortic medial layer and adventitia, especially the adventitia with shock processes. These changes result from different changes of L-arginine transport, NOS activity and its expression in three layers of the aorta from the septic shock rat.     

Changes of nitric oxide synthase and nitric oxide in lung of smoking rats

AIM:To observe the changes of iNOS and eNOS in lung tissue and NO in bronchoalveolar lavage fluid (BALF) in smoking rats.METHODS:80 Wistar rats were divided into control, smoking group, L-NIL group and L-NAME group (rats were exposed to smoke and injected (i.p.) with selective iNOS inhibitor L-NIL or NOS inhibitor L-NAME). iNOS and eNOS protein levels in whole lung were detected by immunohistochemical staining, and NOS mRNA was quantified using RT-PCR. In addition, NO₂^-/NO₃^- was determined using Griess assay.RESULTS:The expression of iNOS mRNA and protein in smoking rats increased, the expression of eNOS mRNA and eNOS protein decreased, and the total cell count and the level of NO₂^-/NO₃^-in BALF increased(P＜0.05). In vivo, L-NIL reduced the total cell count and NO₂^-/NO₃^- in BALF (P＜0.05), while L-NAME had no effect on them.CONCLUSION:Cigarette smoke increased expression of iNOS mRNA and protein and decreased expression of eNOS mRNA and protein. The large amount of NO generated by iNOS may amplify inflammation in lung tissue.     

Immunohistochemistry study on the role of peroxynitrite in diabetic rat osteoporosis

AIM: To explore the role of peroxynitrite (ONOO-) in pathogenesis of diabetic osteoporosis (OP). METHODS: The diabetic rat model was induced by streptozotocin (STZ) for 12 weeks. Bone mineral density (BMD) was measured. HE staining was employed to observe the morphologic changes in bone tissues. The immunohistochemical method was used to detect the content of iNOS and ONOO- in the bone tissues and osteoblasts (OB) cultured at high concentration of glucose. RESULTS: The results showed that high concentration of glucose increased the contents of iNOS and ONOO- in OB. The BMD was decreased and the bone tissues were deteriorated, while iNOS and ONOO- increased in the bone tissues of diabetic rats, which were reversed by aminoguanidine. CONCLUSION: High content of iNOS and ONOO- in bone is probably one factor in diabetic osteoporosis (OP).     

Nitric oxide production,NOS activity and expression in pulmonary arterioles of rats with chronic hypoxic hepercapnic pulmonary hypertension

AIM: To clarify the role of nitric oxide (NO) system in development of chronic hypoxic hypercapnic pulmonary hepertension. METHODS: Male Sprague-Dawley rats were randomly divided into control group and hypoxic hypercapnic group. NO content of plasma was determined, constitutive nitric oxide synthase (cNOS) and inducible nitric oxide synthase (iNOS) were examined using the technique of immunohistochemistry, expression of cNOS mRNA and iNOS mRNA of arteriole were detected by in situ hybridization. RESULTS: Plasma NO concentration, cNOS activity and cNOS mRNA expression in arteriole of chronic hypoxic hypecapnic group were significantly lower than that of control group (P<0.01); activity of iNOS and expression of iNOS mRNA in arteriole showed significantly higher compared with control. CONCLUSION: The disturbance of NO production and NOS expression in arteriole are involved in hypoxic hypercapnic pulmonary hepertension.     

Tetramethylpyrazine combined with aminoguanidine improves renal functions in n0-STZ Wistar rats

AIM: To investigate the effects of tetramethylpyrazine combined with aminoguanidine on the renal functions of neonatal-0 streptozotocin-induced (n0-STZ) rats. METHODS: Neonatal Wistar rats were intraperitoneally injected with a single dose of streptozotocin (STZ) to establish the n0-STZ rat model. The n0-STZ rats were divided into 4 groups: normal control group, insulin resistance group, metformin treatment group and tetramethylpyrazine+aminoguanidine treatment group. Fasting plasm glucose, fasting insulin, insulin resistance index, blood urea nitrogen, serum creatinine, urine albumin and glomerular filtration rate were measured at the 32nd week. The mRNA content of inducible nitric oxide synthase (iNOS) in peripheral blood leukocytes was detected by the technique of in situ hybridization. Nitric oxide (NO) concentration, iNOS activity, the protein expression of iNOS and 3-nitrotyrosine(3-NT) were also assessed in the renal tissues. RESULTS: At the 8th week after the administration of STZ, 82.5% of Wistar rats showed that the fasting plasm glucose level was ≥7.0 mmol/L and the renal functions were seriously damaged. Although both metformin and the combined treatment reduced fasting plasm glucose, fasting insulin and insulin resistance index, the combined treatment was superior in improving the insulin resistance. The damaged renal functions were improved by the combined treatment as reducing blood urea nitrogen and creatinine, increasing glomerular filtration rate were observed. Furthermore, the combined treatment reduced NO concentration, decreased iNOS activity and diminished mRNA content of iNOS, resulting in depressing the generation of 3-NT and iNOS, which surpassed the treatment of metformin. CONCLUSION: Tetramethylpyrazine combined with aminoguanidine improves the renal functions of n0-STZ rats by depressing nitrative stress and enhancing the effect of metformin.     

Effects of PPARβ and NO on high glucose and insulin-induced cardiomyocyte hypertrophy

AIM: To investigate the role of peroxisome proliferator-activated receptor β(PPARβ)-nitric oxide(NO) signal pathway in cardiomyocyte hypertrophy induced by high glucose(25.5 mmol/L) and insulin(0.1 μmol/L)(HGI). METHODS: The cardiomyocyte hypertrophy was characterized in rat primary cardiomyocytes by measuring the cell surface area, protein content, and the mRNA expression of atrial natriuretic factor(ANF). The mRNA and protein expression were measured by real-time PCR and Western blotting, respectively. The activity of NO synthase(NOS) and NO content were measured by a reagent kit through ultraviolet spectroscopy. RESULTS: HGI induced profound change of hypertrophic morphology, and significantly increased the cell surface area, protein content and mRNA expression of ANF(P<0.01), but decreased the expression of PPARβ at mRNA and protein levels(P<0.05). At the same time, the expression of inducible NOS(iNOS) was obviously elevated(P<0.01), which occurred in parallel with the rising NOS activity and NO concentration(P<0.01). GW0742(1 μmol/L), a selective PPARβ agonist, inhibited the cardiomyocyte hypertrophy induced by HGI(P<0.01), and up-regulated the expression of PPARβ at both mRNA and protein levels. Meanwhile, GW0742 also inhibited the increases in iNOS expression, NOS activity, and NO content induced by HGI, which were abolished by GSK0660(1 μmol/L), a selective PPARβ antagonist(P<0.01). CONCLUSION: PPARβ down-regulation and the following iNOS-NO activation are involved in the cardiomyocyte hypertrophy induced by HGI.     

Changes of L-arginine,NOS/NO pathway in adventitia of rats with sepsis

AIM: In this study, we aimed to explore the alteration and pathophysiological significance of the L-arginine (L-Arg)/NOS/NO pathway in the adventitia of rats with sepsis. METHODS: Sepsis was induced by cecal ligation and puncture (CLP). Rat cardiac function was determined. NO generation, NOS activity and L-Arg transport were measured. The iNOS mRNA levels was determined by using RT-PCR. RESULTS: Cecal ligation and puncture induced severe sepsis with severe low glucose, high lacticemia and cardiac function inhibition. The iNOS activity was increased by 2.8-fold compared with controls (P<0.01) and the iNOS mRNA level was elevated-6-fold (P<0.01). The NO level in plasma and incubation media (incubation for 40 min) in the sepsis group was increased by 144% and 273% (both P<0.01), respectively. CONCLUSION: The results demonstrated that the L-Arg,NOS/NO pathway was activated in vascular adventitia of rats with sepsis shock. The aortic adventitia L-Arg/NOS/NO pathway might play an important role in the pathogenesis of sepsis and septic shock.     

Effects of aspirin on production of nitric oxide and inducible nitric oxide synthase mRNA expression under inflammatory conditions in human vascular endothelial cells

AIM: To explore the effect of aspirin on inducible nitric oxide synthesis and gene expression under inflammation in endothelial cells. METHODS:Using NADPH, Griess methods and RT-PCR, the activity of isozymes of NO synthase (NOS), nitric oxide (NO) level, and iNOS mRNA expression were examined respectively. Also, the lactate dehydrogenase (LDH) release rate, malondialdehyde (MDA) content and cell viability were measured. RESULTS: Aspirin (3 mmol/L) reduced inducible NO production and NOS activity(P＜0.05), caused a significant decrease in LDH release rate and MDA content with a further increase in cell viability. Aspirin inhibited inducible NO excretion and alleviated the damage caused by NO in a concentration-dependent manner. However,aspirin had no effect on basal NO levels in the absence of stimulation by inflammatory factor. On the other hand, under middle concentration (＜10 mmol/L), aspirin was able to reduce enzymatic activity of NOS and protein expression by increasing the stability of iNOS mRNA. In contrast, at high concentration (20 mol/L), aspirin could decrease the stability of iNOSmRNA. Sodium salicylate and indomethacin did not inhibit inducible NO production. CONCLUSION:Aspirin could significantly inhibit inducible NO production in vascular endothelial cells during inflammation.     

Effect of altitude hypoxia on glutamate,aspartate and NOS in the rat hypothalamus

AIM: To investigate the effects of external counterpulsation (ECP) on nitric oxide (NO) and nitric oxide synthase (NOS) and the expression of NOS gene in myocardial infarction canines. METHODS: Nineteen healthy dogs were randomly divided into three groups ie. controls, ischemia group, ischemia and ECP group. Serum NO concentrations and myocardium NO levels and NOS specific activity were determined by modified nitrate reductase method. The protein synthesis of sub-type NOS including inducible NOS (iNOS) and endothelial NOS (eNOS) of myocardial tissue were also determined by immunohistochemical method. The constitutive NOS (cNOS) mRNA was measured via in situ hybridization. RESULTS: 120 and 180 minutes after the ligating of LAD, serum NO concentration in ECP groups were higher than those in ischemic groups (P＜0.05). The NO levels and NOS specific activity in myocardium of ischemic dogs were lower than those in controls and ECP group (P＜0.05). Protein synthesis of iNOS increased and that of eNOS decreased in ischemic myocardium. But ECP could control the protein synthesis of iNOS, and increase that of eNOS. Further studies showed that the expression of cNOS mRNA decreased in ischemic myocardial tissue, ECP might promote the expression of it and regulate NOS in the gene level. CONCLUSION: The results suggested that it was one of the most important mechanisms through raising the NO levels to protect ischemic myocardium in ECP.     

Effects of external counterpulsation on nitric oxide system in myocardial infarction canines

AIM:To investigate the effects of external counterpulsation(ECP)on nitric oxide(NO)and nitric oxide synthase(NOS)and the expression of NOS gene in myocardial infarction canines.METHODS:Nineteen healthy dogs were randomly divided into three groups ie.controls, ischemia group, ischemia and ECP group.Serum NO concentrations and myocardium NO levels and NOS specific activity were determined by modified nitrate reductase method.T he protein synthesis of sub-type NOS including inducible NOS(iNOS)and endothelial NOS(eNOS)of myocardial tissue were also determined by immunohistochemical method.The constitutive NOS(cNOS)mRNA was measured via in situ hybridization.RESULTS:120 and 180 minutes after the ligat ing of LAD, serum NO concentration in ECP groups were higher than those in ischemic groups(P<0.05).The NO levels and NOS specific activity in myocardium of ischemic dogs were lower than those in controls and ECP group(P<0.05).Protein synthesis of iNOS increased and that of eNOS decreased in ischemic myocardium.But ECP could control the protein synthesis of iNOS, and increase that of eNOS.Further studies showed that the expression of cNOS mRNA decreased in ischemic myocardial tissue, ECP might promote the expression of it and regulate NOS in the gene level.CONCLUSION:The results suggested that it was one of the most important mechanisms through raising the NO levels to protect ischemic myocardium in ECP.     

Effects of cholecystokinin octapeptide on cerebral cortex injury during endotoxic shock

AIM: To study the effects of cholecystokinin octapeptide (CCK-8) on cerebral cortex injury during endotoxic shock (ES) and its mechanisms. METHODS: Rabbits were injected intravenously with lipopolysaccharide (LPS, 8 mg/kg) to establish ES model. Rabbits (n=32, 8 in each group) were randomly assigned to receive one of four treatments intravenously: normal saline (as control), LPS, CCK-8 pretreatment 30 min before LPS, proglumide (Pro, nonspecific antagonist of CCK receptors) pretreatment 30 min before LPS. The changes of mean arterial pressure (MAP) were measured. The morphologic changes in cerebral cortex were observed through light microscope (LM) and transmission electron microscope (TEM). The alterations of activities of nitric oxide synthase (NOS) and superoxide dismutase (SOD), contents of nitric oxide (NO) and malondialdehyde (MDA) in cerebral cortex were assayed. The expressions of protein of inducible NOS (iNOS) and neuronal NOS (nNOS) were detected by immunohistochemistry staining in cerebral cortex in 4 groups of Sprague-Dawley (SD) rats (n=12, 3 in each group) which were grouped as that of the rabbits. RESULTS: LPS administration resulted in lower MAP than that in control group (P<0.01). Hydropic degeneration of neurons and severe injuries to capillaries were observed in cerebral cortex of ES rabbits. LPS administration induced the expression of iNOS protein in the cytoplasm of neurocytes, and lead to stronger positive signals of nNOS than that in control group. NOS activity, NO2ˉ/NO3ˉ level and MDA content were higher (P<0.05, P<0.01 and P<0.01), while SOD activity was lower in cerebral cortex of ES rabbits than those in control group (P<0.01). CCK-8 pre-administration alleviated the changes induced by LPS, while Pro pre-administration aggravated those alterations. CONCLUSION: CCK-8 protects brain tissues against the injury induced by LPS, which may be associated with its effects of suppressing the overproduction of NO and free radicals.     

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.     

The cytotoxicity of nitric oxide induced by inflammatory cytokine in combination with LPS in endothelial cells

AIM: To explore the mechanism underlying inducible nitric oxide (NO) caused injury of endothelial cells during inflammation. METHODS:The activity of iso-enzymes of NO synthase (NOS), NO level and iNOS expression were examined using NADPH method, Griess reaction and RT-PCR, respectively. Furthermore, the lactate dehydrogenase (LDH) release rate, malondialdehyde (MDA) content were also measured. RESULTS:Co-administration of cytokines (TNF-α 5×10⁵ U/L, IL-1β 2×10⁵ U/L, INF-γ 2×10⁵ U/L) and LPS (10 mg/L) caused an obvious increase in NOS activity, NO levels (about two-fold) and a significant injury of the cells. At the same time, a significant increase in iNOS mRNA was also detected. Wheareas, treatment of the cells separately with cytokines or LPS for 24 h had no significant effect on NOS activity and NO level in cell lysates, however, it caused a significant increase in LDH release and MDA content. Also, the effect of cytokines and LPS on cell viability was concentration-and time-dependent. L-NMMA, a inhibitor of NOS, can suppress inducible NO production and protect cells against NO induced injury. CONCLUSION:Co-administration of cytokines (TNF-α, IL-1β and INF-γ) and LPS significant activated iNOS and NO production which, in turn, induced oxidative reaction in endothelial cells.     

Protective effects of extract of Ginkgo biloba on diaphragm of diabetic rats

AIM: To investigate the effects of extract of Ginkgo biloba (EGb) on diaphragm from diabetic rats. METHODS: Sprague-Dauley rats were divided into three groups: normal control, diabetic group and EGb treatment group. The morphologic changes of diaphragm tissues were studied by light and electron microscopy, the activities of succinate dehydrogenase (SDH), superoxide dismutase (SOD), nitric oxide synthase (NOS) and contents of malondialdehyde (MDA), nitric oxide (NO₂^-/NO₃-) in the diaphragm mitochondria were assayed by spectophotometer, respectively. RESULTS: The activities of SOD, SDH decreased in diabetic diaphragm mitochondria, but the activitiy of NOS, the contents of NO₂^-/NO₃^-, MDA increased compared with control group. The activities of SOD, SDH were increased as well as NOS were decreased and the contents of NO₂^-/NO₃^-, MDA decreased in EGb treatment group compared with the diabetic group. CONCLUSION: EGb may protects the diaphragm mitochondria of diabetic rats by enhancing the function of respiratory chain, anti-oxidation and decreasing NO level.     

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.