Protective effects of tongxinluo,carvedilol and valsartan on microvascular endothelial function and integrity after late reperfused AMI in rabbits

AIM:To compare the protective effects of tongxinluo, a Chinese medicine, and carvedilol and valsartan on myocardium microvascular endothelial function and integrity after late reperfusion of acute myocardial infarction (AMI) in rabbits. METHODS:Forty-eight rabbits were randomly assigned to the following groups:(1) sham operated rabbits;(2) ischemia-reperfusion (I-R) controls;(3) tongxinluo (1.0 g·kg^-1·d^-1);(4) carvedilol (5 mg·kg^-1·d^-1);(5) valsartan (10 mg·kg^-1·d^-1) and (6) ticlopidine + aspirine (30 and 20 mg·kg^-1·d^-1, respectively) groups. After 3 d of drug treatment, the left coronary artery in the rabbit was ligated for 2 h and loosed subsequently for another 2 h. The serum levels of nitric oxide (NO₂^-/NO₃^-) and endothelin (ET) at baseline before AMI, 2 h after both AMI and reperfusion were examined. Also, the number of circulating endothelial cells (CEC), MI size and percentage myocardium focal bleeding incidence were determined 2 h after reperfusion. RESULTS:(1) The baseline level of NO₂^-/NO₃^- was significantly higher in tongxinluo group than that in other groups (all P<0.01), whereas the content of ET was not significantly different among the groups. 2 h after both AMI and reperfusion, NO₂^-/NO₃^- was significantly reduced (P<0.05, P<0.01) and ET was significantly increased in each group as compared with their baseline (P<0.05, P<0.01). Yet among the groups, NO₂^-/NO₃^- was still significantly higher and ET was significantly lower in tongxinluo-treated group than that in the other groups (P<0.05, P<0.01). (2) CEC number was significantly increased in I-R controls as compared with sham group (P<0.01), and was significantly reduced in the tongxinluo-treated groups as compared with I-R controls (P<0.05). (3) MI size was significantly reduced in the four treatment groups as compared with I-R controls (all P<0.01). (4) The percentage of myocardium focal bleeding incidence was significantly lower in tongxinluo and valsartan-treated groups than that in I-R controls (P<0.05, P<0.01). CONCLUSION:Tongxinluo as well as valsartan effectively protectsmyocardium endothelial function and integrity during AMI and late reperfusion,with the effects of tongxinluo being superior.     

Effects of different doses of L-dopa on rotational behavior and amounts of cells expressing D2 receptors in hemiparkinsonian rats

AIM：To observe the effects of different doses of L-dopa on the rotational behavior and amounts of cells expressing D₂ receptors in striatum in hemiparkinsonian rats.METHODS：A hemiparkinsonian model was established in rats by pretreatment with 6-hydroxydopamine.The D₂ receptor expression were detected by immunohistochemical staining.The numbers of rotations induced by apomorphine was counted within 30 min before and after L-dopa (10 mg·kg^-1·d^-1,50 mg·kg^-1·d-^-1 or 100 mg·kg^-1·d^-1,ip) was introduced to Parkinson’s disease (PD) model rats for 15 days.RESULTS：In successful PD model rats,the increased percentage of D₂ receptor in lesioned side compared with intact side was associated linearly with the numbers of rotations within 30 min (r=0.927,P<0.01).After high dose of L-dopa intervention to PD model,the numbers of rotations decreased significantly (P<0.05),the amounts of cells expressing D₂ receptor at the lesioned side striatum decreased significantly (P<0.01).CONCLUSION：After high dose of L-dopa intervention,rotation behavior of PD rats improves,and D₂ receptor is down-regulated significantly.     

Effect of pioglitazone on glucose metabolism and PPAR-γ expression in lipid-infused rats

AIM: To investigate the effect of pioglitazone (Pio) on glucose metabolism and peroxisome proliferators-activated receptor (PPAR)-γ expression in free fatty acid (FFA) -induced insulin resistance in rats. METHODS: A hyperinsulinaemic-euglycaemic clamp and ［3-3H］-glucose tracing technique were used in awake rats. Glucose metabolism in vivo and PPAR-γ in adipose tissue expression were assessed with elevation FFA by lipid infusion over 4 h in rats pretreated with or without Pio.RESULTS: During steady-state of clamp, there was a significant increase in plasma FFA in two lipid-infused groups, compared to control rats (P<0.01). The glucose infusion rates (GIR) in Pio-treated rats (P/L group), compared with controls, were significantly reduced ［(20.6±0.4) mg·kg^-1·min^-1 vs (33.6±0.6)mg·kg^-1· min^-1, P<0.01］, whereas the GIR was lower in the lipid group (L group) than that in the P/L group［(12.6±0.8) mg·kg^-1·min^-1 vs (20.6±0.4) mg·kg^-1·min^-1, P<0.01］. The hepatic glucose production (HGP) was significantly suppressed (85%) ［(18.3±2.1)mg· kg^-1·min^-1 (basal) vs (2.7±2.4)mg· kg^-1·min^-1, and (17.5±2.6) mg· kg^-1·min^-1 vs (2.6±1.0)mg· kg^-1·min^-1］, all P<0.01 during clamp in control and P/L groups. The suppressive effect of insulin on HGP was significantly blunted in L group［(17.3±2.1)mg· kg^-1·min^-1 vs (15.8±1.5)mg· kg^-1·min^-1］. The rate of glucose disappearance (GRd) was significantly reduced in two lipid-infused rats compared with controls［(26.6±1.6)mg· kg^-1·min^-1 and (23.2±0.9)mg· kg^-1·min^-1 vs (37.7±2.6)mg·kg^-1·min^-1,P<0.01］. The PPAR-γ expression of adipose tissue in P/L group was significantly upregulated. CONCLUSION: Lipid-infusion induces an acute insulin-resistance in vivo. Pio treatment upregulates the PPAR-γ of adipose tissue and suppresses HGP. Pio can protect partly against lipid-induced insulin resistance.     

Protective effects of pioglitazone on endothelial function in rats with hypercholesterolemia

AIM: To investigate the effects of pioglitazone,a PPARγ agonist,on endothelial cell (EC) dysfunction in hypercholesterolemic rats.METHODS: 36 healthy male Wistar rats were assigned to one of the following groups randomly (six rats in each group): control,hypercholesterolemia (HC),and HC treated with pioglitazone 1.5 mg·kg^-1·d^-1,3 mg·kg^-1·d^-1,10 mg·kg^-1·d^-1 and 20 mg·kg^-1·d^-1 (HC＋PIO),respectively.EC function was determined by comparing vasorelaxation to ACh,an EC dependent vasodilator,and acidified NaNO₂,an EC-independent vasodilator.Maximal positive and negative values of the instantaneous first derivative of LVP (+dp/dt_max and dp/dt_max) were determined by MS2000 system.RESULTS: (1) Hypercholesterolemia caused a significant endothelial diastolic dysfunction (maximal relaxation to ACh: 50.51%±2.45% vs 99.78%±3.01% in control,P<0.01).(2) Treatment with pioglitazone relieved EC-dependent vasodilatation in a dose dependent manner,and 10 mg·kg^-1·d^-1 is the best dose.(3) Pioglitazone not only improved EC function,but also reduced cardiac functional injury induced by hypercholesterolemia.CONCLUSION: EC dysfunction induced by hypercholesterolemia can be directly extenuated by pioglitazone,which may effectively prevent from subsequent atherosclerosis and ischemic heart disease.     

Effects of bilirubin on oxygen free radicals and caspase-3 in acute lung injury rats

AIM:To investigate the mechanisms by which bilirubin inhibits acute lung injury (ALI). METHODS:30 female Wistar rats were divided into normal group, ALI group and bilirubin treatment group. ALI was induced by intravenous injection of LPS. The contents of OH^-, H₂O₂ and O₂^· in the lung as well as the expression of caspase-3 in the lungs were investigated. RESULTS:(1) The contents of OH^-, H₂O₂ and O₂^· in the lung homogenate and the expression of caspase-3 in the lungs in ALI group increased compared with those in normal group (P<0.05). (2) The contents of OH^-, H₂O₂ and O₂^· in the lung homogenate and the expression of caspase-3 in the lungs in bilirubin treatment group increased compared with those in normal group, but decreased compared with those in ALI models (P<0.05). CONCLUSION:(1) Bilirubin was shown to be able to ameliorate apoptosis in ALI rats. (2) The increase in the contents of OH^-, H₂O₂, O₂^· in ALI group indicated the development of oxidative lung injury, which was ameliorated by bilirubin. (3) Expression of caspase-3 confirmed that the model made by LPS was associated with apoptosis, which was reduced by bilirubin.     

Influences of Vit-E on the mtDNA damage and Ca2+ homostasis of hippocampus and antioxidative ability in brain of aging mice induced by D-galactose

AIM: To study the influences of vitamin E (Vit-E) on the mtDNA damage and Ca²⁺ homeostasis in hippocampus and antioxidative ability in aging brain induced by D-galactose.METHODS: D-galactose (1 000 mg·k^-1·d^-1 ) was injected into mice hypodermically for 8 weeks to induce aging animal model, and Vit-E (100 mg·kg^-1; 250 mg·kg^-1) was administered for 6 weeks by ig at the 3rd week of making model. After Vit-E treatment for 8 weeks, water maze test was used to determine the ability of mice’s learning and memory. The activities of glutathione peroxidase (GSH-Px) and succinate dehydrogenase (SDH), the content of nitric oxide (NO) and activity of nitric oxide synthase (NOS) in the brain tissue were detected separately. Fura-2/AM, double-wave-length fluorospectrophotometer and PCR method were used to measure the concentration of calcium ion and mtDNA mutation in the hippocampus cells.RESULTS: Administration of Vit-E improved significantly the ability of learning and memory in model mice, inhibited the activity of NOS and decreased the amount of NO, and increased the activities of GSH-Px and SDH respectively in brain tissues, decreased the concentration of calcium ion (P<0.01, P<0.05), and prevented the damage of mtDNA in hippocampus.CONCLUSION: Vit-E can enhance the antioxidative ability, regulate the homeostasis of Ca²⁺ and inhibit the damage of mtDNA caused by oxidative stress in aging brain, and improve the ability of learning and memory in aging mice.     

Preventive effect of 3,4-dihydroxyacetophenone on atherosclerosis and role of visfatin expression

AIM: To observe the preventive effect of 3,4-dihydroxyacetophenone (DHAP) on atherosclerosis (AS) and the role of visfatin expression in ApoE(-/-) mice.METHODS: Eight-week-old normal mice were used in normal control group (n=8). Eight-week-old male ApoE (-/-) mice were randomly divided into 3 groups: AS group (n= 8, im. NS), DHAP treatment group (n=8, im. DHAP 10 mg·kg^-1·d^-1) and simvastatin treatment group (n=8, im. simvastatin 10 mg·kg^-1·d^-1). All mice were fed with Western diet (21% fat, 0.15% cholesterol) for 12 weeks. The blood samples were collected and the concentrations of blood lipids and visfatin were detected. The frozen sections of aortic root were stained with oil red O. The visfatin in atherosclerotic plaques at aortic roots was examined by Western blotting. The structures of smooth muscle cells and endothelial cells were observed under electron microscope. RESULTS: In DHAP-treated mice, the concentrations of visfatin, TG and TC were decreased, the formation of AS plaque was reduced, the injuries of smooth muscle cells and endothelia cells were attenuated. Visfatin was also decreased at atherosclerosis plaque in DHAP-treated mice.CONCLUSION: DHAP effectively prevents and treats AS by inhibiting the production of visfatin and reducing lipid.     

Role of injury and phenotype shift of liver sinusoidal endothelial cells in the development of portal hypertension of cirrhosis in rats

AIM: To study the role of injury and phenotype shift of liver sinusoidal endothelial cells in the development of portal hypertension of liver cirrhosis in rats. METHODS: The rat liver cirrhosis model was established by peritoneal injection of dimethylnitrosamine (DMN) (at a dose of 10 mg·kg^-1, 3 times a week, for 4 weeks). The dynamic changes of liver cirrhosis were observed at different time points (1 day, 2 days, 3 days, 1 week, 2 weeks, 4 weeks, 6 weeks and 8 weeks). The pressure of portal vein (Ppv), the expression of CD44, von Willebrand factor (vWF), endothelin-1 (ET-1) mRNA and endothelial nitric oxide synthase (eNOS) mRNA, the serum hyaluronic acid (HA) content and liver ET-1 content were measured. RESULTS: Compared with the normal control rats, CD44 positive staining was weak in the 1 day model rats, and the numbers of fenestrae of sinusoidal endothelial cells (SECs) rapidly decreased, but serum HA content rapidly increased (P<0.05). vWF positive staining in the 2-day model rats was stronger than that in normal control rats (P<0.05). There was a positive correlation between the Ppv and the vWF expression, serum HA content in the DMN-induced liver cirrhosis rats (P<0.05). Compared with the normal control rats, ET-1 mRNA expression increased in the 2-day and 3-day model rats, and ET-1 content lightly increased. eNOS mRNA expression was stronger in the 1-day, 2-day and 3-day model rats than that in normal control rats, meanwhile eNOS always expressed at a low level. CONCLUSION: The injury and phenotype shift of SECs is a pathological basis in the development of portal hypertension of DMN-induced liver cirrhosis in rats. Imbalance of ET-1 and NO production increases intrahepatic resistance, which plays an important role in the development of portal hypertension.     

Effect of angelica on myocardial fibrosis post myocardial infarction in rats

AIM: To investigate 1) the role of transforming growth factor-β₁ (TGF-β₁) and macrophage infiltration during the development of myocardial fibrosis (MF) in rats after myocardial infarction (MI);and 2) mechanisms of MF post-MI and the inhibitory effect of angelica.METHODS: Sprague-Dawley (SD) rats were subjected to MI by ligating the left anterior descending coronary artery.The animals were randomly divided into three groups: sham, MI and MI+angelica.After 24 hours of ligation, rats received angelica (20 mL·kg^-1·d^-1, ip) or saline.Left ventricular hemodynamics were measured and rats were killed at week 1, week 2 and week 4, respectively.Collagen content, macrophage infiltration and TGF-β₁ expression were examined in the non-infarcted area.RESULTS: ① In MI group, the numbers of macrophage and TGF-β₁ expression were significantly upregulated compared to sham at week 1 post-MI and remained elevated at week 4 (P<0.01).Angelica significantly decreased macrophage infiltration and TGF-β₁ expression (P<0.01 vs MI).② Collagen content was increased significantly in MI group compared to sham at week 2 and week 4 (P<0.01), and decreased in MI+angelica group (P<0.05 vs MI).③ Cardiac function was markedly decreased post-MI in MI group (P<0.01), and improved at week 4 in MI+angelica group (P<0.05).CONCLUSION: In MF post-MI, angelica may have an antifibrotic effect by decreasing macrophage infiltration and TGF-β₁ expression, by which reactive myocardial fibrosis is reduced, and cardiac function is improved.     

Effects of heroin at different concentrations on electrophysiological properties of rat hippocampal CA1 pyramidal neurons

AIM: To investigate changes of electrophysiological properties of rat hippocampal CA1 pyramidal neurons in perfusion with heroin at different concentrations. METHODS: The intracellular recordings were made from CA1 pyramidal neurons of isolated hippocampal slices in perfusion with 0.03-0.3 mmol·L-1 heroin. Compared with control parametes before herion perfusion, the electrophysiological data obtained from identical neurons at 15 min after acute perfusion of the different concentration heroin were analyzed. RESULTS: With the increase of the heroin concentrations in perfusion, the absolute values of neuron resting potential and threshold potential decreased (P<0.05). In 0.3 mmol·L-1 heroin perfusion group，the amplitude of action potential decreased （P<0.05）, 10%-90% risetime and 10%-90% decaytime of spike potential elongated （P<0.05， P<0.01）, and I-V relation curve indicated membran slope resistance increased in 0.1-0.3 mmol·L^-1 perfusion group （P<0.05，P<0.01）. I-F relation curve showed that neuron average firing frequency recored at 15 min after 0.03 mmol·L^-1 heroin infusion was similar to the control frequency when intracellular stimulus intensity was 0.1-1.8 nA, however, firing frequency kept the higher level （P<0.05，P<0.01） in 1.9-2.0 nA vs the control frequence. It was evident that EPSPs of pyramidal neurons were inhibited in perfusion of three concentration heroin, especially in 0.3 mmol·L^-1. CONCLUSION: These results indicate acute heroin perfusion has a significantly influence on electrical activities of hippocampus CA1 pyramidal neurons.     

Effect of fluvastatin on left ventricular remodeling and caspase-3 expression after myocardial infarction in rats

AIM: To observe the effect of fluvastatin (FV) on left ventricular remodeling and expression of caspase-3 after myocardial infarction (MI) in rats. METHODS: Rats were divided into 4 groups: group Ⅰ (sham), group Ⅱ (sham+FV), group Ⅲ (MI) and group Ⅳ (MI+FV). group Ⅱ and Ⅳ were treated with FV (10 mg·kg^-1·d^-1) for 4 weeks. The left ventricular structure, echocardiography and hydroxyproline were observed. The expression of caspase-3 was measured by immunohistochemistry and RT-PCR. RESULTS: Compared with MI group, there was a improvement of ultrastructure and index of left ventricular remodeling, and decrease in hydroxyproline in MI+FV group (all P<0.05). The number of caspase-3 positive cells also decreased in MI+FV group, and RT-PCR showed the level of caspase-3 mRNA expression was lower than that in MI group (P<0.05). CONCLUSION: Fluvastatin improves left ventricular remodeling after myocardial infarction, decreases the expression of caspase-3 and inhibits apoptosis.     

Effects of angiotensionⅡon metalloproteinases and matrix in hypertrophied myocardium from infarcted rats

AIM: To investigate the roles of angiotensionⅡ (AngⅡ) receptors (AT₁, AT₂) antagonists on matrix metalloproteinases (MMPs) and extracellular matrix (ECM) system in septal myocardium from infarcted rats.METHODS: The model of rat myocardium infarction (MI) was established by permanent ligation of the left coronary artery. The treatments of the AT₁ receptor antagonist valsartan (10 mg·kg^-1·d^-1) or AT₂ receptor antagonist PD123319 (30 mg·kg^-1·d^-1) were started 7 days prior to surgery. On day 14 after MI, protein levels of MMP-2, 3, 9, fibronectin (FN), tenascin-C (TN-C) in interventricular septum (IS) were determined. The distributions of FN and TN-C were also determined by immunofluorescence.RESULTS: Pathological changes of IS on day 14 after MI showed typical myocardial hypertrophy. Protein expressions of MMP-2, 3, 9 and TN-C of IS in banding group were higher than those in sham-operation group (P<0.01). The expressions of TIMP-1 and FN were lower than those in sham-operation group (P<0.01). Protein expressions of MMP-2, 3, 9 and TN-C in valsartan group were obviously lower than those in banding and PD123319 groups (P<0.01). TIMP-1 and FN protein expressions in valsartan group were higher than those in banding and PD123319 groups (P<0.01). No difference between banding and PD123319 groups was observed (P>0.05).CONCLUSION: AngⅡis involved in myocardium remodeling in infarcted rats, which is mediated via AT₁ receptor to degrade matrix by MMPs. The heart protection of AT₁ receptor antagonists may relate to inhibition of MMPs.     

Effect of doxycycline on matrix metalloproteinase activity and vascular remodeling in balloon-injured rat carotid arteries

AIM:To examine the inhibition of matrix metalloproteinase (MMP) activity by doxycycline (Doxy) and its effect on vascular smooth muscle cells (SMCs) proliferation,neointimal hyperplasia and vascular remodeling.METHODS: The model of rat common carotid artery injury was established by balloon-dilatation.Doxy was administered to the animals of treatment group at dose of 30 mg·kg^-1·d^-1.The activity of MMPs in the tissue of injured carotid arteries was measured by gelatin zymography.The thickness and area of neointimal,lumen area and the proliferation of SMCs were measured by histological and morphometric analysis.RESULTS:1.After Doxy treatment,the activity of MMP-9 in the carotid arteries was reduced by 26.3% and 34.5% compared to that in rats without Doxy treatment at 24 hours and 3 days after balloon injury,respectively (P<0.01).The activity of MMP-2 was also reduced by 40.0% at 7 days after injury (P<0.01).2.The thickness of neointimal were significantly decreased by 32.0% and 38.8% (P<0.01) and the lumen area was increased by 58.0% and 90.4 % at 14 and 28 days after injury in the Doxy-treated rats compared to those in control rats,respectively (P<0.01).Doxy treatment significantly reduced intimal SMCs proliferation from 62.76%±1.02 % in the controls to 43.23%±1.06% at 7 days after injury (P<0.01).CONCLUSION: Doxy treatment inhibits the activity of MMPs,the SMCs proliferation of intimal,neointimal hyperplasia and vascular remodeling,suggesting that Doxy treatment is useful in preventing restenosis after PTCA.     

Porcine surfactant in treatment of LPS-induced early-stage acute lung injury in rats

AIM: To evaluate the therapeutic efficacy of intratracheal instillation of porcine pulmonary surfactant (PPS) in rats with lipopolysaccharides (LPS)-induced early-stage ALI in this study.METHODS: SD rats weighing 200 g-300 g were randomly divided into 4 groups: LPS (1.5 mg·kg-1)+saline,LPS+PPS 100 mg·kg^-1,LPS+PPS 150 mg·kg^-1,LPS+PPS 200 mg·kg^-1.The PaO₂ and PaCO₂,as well as survival rate of rats were examined for 6 h after the start of PPS-instillation.Then,rats were killed and lungs were immediately removed for lung index (LI) and histological analysis.The bronchoalveolar lavage fluid (BALF) was collected for measurement of total protein (TP) contents,TNF-α level and white blood cell(WBC) numbers.RESULTS: Significantly increased PaO₂,reduced mortality rate,decreased total protein and TNF-α contents in BAL,as well as lung index and meliorated histological appearance were observed in three PPS-treated groups compared with group given saline after LPS (P<0.05).The therapeutic effect in PPS150 and PPS200 groups was better than that in PPS100 group.CONCLUSION: Intratracheal PPS instillation provides protective effect on acute lung injury in rats induced by LPS.     

Astragali radix extract ameliorates renal resistance to atrial natriuretic peptide in rats with experimental nephrotic syndrome

AIM: To study the effects of astragali radix extract (ARE) on renal resistance to atrial natriuretic peptide (ANP) in rats with experimental nephrotic syndrome. METHODS: Male Sprague-Dawley rats were randomly divided into normal control, adriamycin nephropathy (ADR), ADR treated with ARE (2.5 g· kg^-1· d^-1) and ADR treated with benazepril (10 mg· kg^-1· d^-1). After 6 weeks, rats received intravenous infusion of 2% body weight isotonic saline. Urinary cGMP excretion (U_cGMPV), plasma ANP level, renal PDE5 activity and protein expression were also detected. RESULTS: ARE increased U_NaV while ACEI was not natriuretic. Nephrotic rats had a blunted natriuretic response and reduced rate of U_cGMPV after volume expansion despite higher plasma ANP concentration. ARE increased U_cGMPV and restored partly natriuretic response to volume expansion. The activity and protein abundance of renal PDE5 were high in nephrotic rats. ARE significantly reduced the PDE5 activity and protein expression. CONCLUSION: ARE may ameliorate the renal resistance to ANP in rats with adriamycin nephropathy by inhibiting the PDE5.     

Selenium-enriched Spirulina platensis promotes proliferation of hepatocytes in rat partial hepatectomy

AIM: To explore the effects of selenium-enriched Spirulina platensis (Se-SP) on proliferation of hepatocytes in rat hepatectomy. METHODS: Rat hepaectomy model was conducted using male Wistar rats. The rats were randomized into five groups: operation groups with 150 (H), 50 (M) and 15 (L) mg·kg^-1·d^-1 of Se-SP, placebo-control (P) and sham operation group (F). Activities of glutathione peroxidase (GPx) and thioredoxin reductases (TR) in hepatocytes were determined by chemical colorimetry. The expression index of proliferating cell nuclear antigen (PCNA) in hepatocytes was detected by immunohistochemistry, and the level of ［³H］-TDR incorporation in regenerative hepatocytes was analyzed by radio-immunity. RESULTS: Activity of GPx and TR, PCNA expression index as well as ［3H］-TDR insertion in hepatocytes (in vitro) were obviously higher (P<0.05) in L groups than those in P and F groups. All parameters were significant changed (P<0.05) after operation in H, M, L and P groups whereas some slightly change in F group. Furthermore, correlation analysis showed that the levels of GPx and TR in hepatocytes all showed positive correlation with PCNA expression (r²=0.77 and 0.87, respectively) and with ［³H］-TDR incorporation level (r² = 0.73 and 0.84, respectively) in hepatocytes. CONCLUSION: Se-SP enhances hepatocyte proliferation in rat hepatectomy, up-regulation of selenoenzymes might be responsible for this effect.     

Rifampicin protects rats against rotenone-induced dopaminergic neurons damage

AIM:To investigate the protective effect of rifampicin on rotenone-induced apoptosis of dopaminergic neurons and expression of α-synuclein in rats. METHODS:Highly selective lesions and high expression of α-synuclein in nigrostriatal dopaminergic neurons in rats were induced by chronic subcutaneous exposure to rotenone at dose of 1.5 mg·kg^-1·d^-1 for 3 weeks. At the same time, rifampicin was administered at dose of 30 mg·kg^-1·d^-1 by intragastric administration for 3 weeks. The changes of behavior, pathology and immunoreactivity of TH and α-synuclein in SNc were observed. RESULTS:Obvious changes of behavior, pathology and TH immunoreactivity in SNc were observed in male SD rats injected subcutaneously with rotenone and rifampicin protected rats against these toxic effects induced by rotenone. CONCLUSION:Rifampicin has extensive protective effects against rotenone-induced neurotoxicity, which is related to inhibiting the expression and aggregation of α-synuclein.     

Effects of thalidomide on the expression of NF-κB and TNF-α in experimental hepatic fibrotic rats

AIM: To study the effects of thalidomide on the expressions of nuclear factor κB (NF-κB) and tumor necrosis factor-α (TNF-α) in rat liver fibrosis.METHODS: The fibrosis of rat liver was induced by intraperitoneal injection of carbon tetrachloride thrice weekly.Meanwhile thalidomide (10 mg·kg^-1·d^-1 or 100 mg·kg^-1·d^-1) was given daily by the intragastric route for 8 weeks.Serum alanine aminotransferase (ALT),aspartate aminotransferase (AST),prealbumin (PA),hyaluronic acid (HA) and laminin (LN),and hydroxyproline (HYP) contents in the liver,NF-κB p65 and α-smooth muscle actin (α-SMA) protein in the liver,IκBα and TNF-α protein in cytoplasm and NF-κB p65 protein in nucleus and TNF-α mRNA levels in the liver were studied.RESULTS: Compared with the model group,the Knodell score,serum ALT,AST,HA,LN levels and HYP contents in liver,NF-κB p65 protein in nucleus and α-SMA protein in the liver,and TNF-α mRNA and protein in the liver of rats given high dose of thalidomide were decreased significantly (P<0.01).Meanwhile PA level and IκBα protein in cytoplasm were elevated significantly (P<0.01).CONCLUSION: Thalidomide exerts its effect on the down-regulation of NF-κB-induced TNF-α via inhibiting dissociation and degradation of IκB and prevents liver fibrosis in rats.     

Intervention of Lipo-PGE1 on liver blood perfusion by different time and medication: a empirical study

AIM: To explore the effect and mechanism of liposome prostaglandin E₁(Lipo-PGE₁) on liver blood perfusion by different time and medication.METHODS: Twelve healthy adult dogs were injected with Lipo-PGE₁₁ μg/kg via left small saphenous vein at speed of 0.05 μg·kg^-1·min^-1.Liver computed tomography perfusion imaging (CTPI) was performed on 0,5,15 and 30 min,and the value of hepatic arterial perfusion (HAP),portal vein perfusion (PVP) and total liver perfusion (TLP) among groups were compared.The impacts of Lipo-PGE₁ on liver haemodynamics at different time were investigated.Twenty-four health dogs were randomly divided into four groups: control group,peripheral vein group,hepatic artery group and superior mesenteric artery group.Liver CTPI was performed at 5 min after 1 μg/kg Lipo-PGE₁ administration in those groups.The values of HAP,PVP and TLP were compared and effects of Lipo-PGE₁ on liver blood flow by different medication were observed.RESULTS: The values of liver perfusion (mL·min^-1·mL^-1) at 0,5,15 and 30 min after 1 μg/kg Lipo-PGE₁ administration via vein were as follows: HAP: 0.22 ±0.65,0.24±0.65,0.22±0.69,0.22±0.06;PVP: 1.22±0.40,1.88±0.59,1.55±0.55,1.29 ±0.57;TLP: 1.44±0.42,2.12±0.61,1.77±0.56,1.51±0.58,respectively.No significant difference in HAP among groups was observed,but in PVP and TLP,significant differences (F=3.812,P<0.05;F=3.805,P<0.05) among groups were found.The values of PVP and TLP were most obviously increased at 5 min,and the values of PVP and TLP were still on the high level at 15 min and 30 min.The values of liver perfusion (mL·min^-1·mL^-1) by different medication were as fellows: HAP: 0.22±0.06,0.24±0.06,0.31±0.07,0.26±0.05;PVP: 1.28±0.38,2.33±0.41,2.37±0.55,2.83±0.94;TLP: 1.50±0.40,2.57±0.42,2.67± 0.58,3.09±0.94,respectively.No significant difference in HAP among groups (F=2.248,P>0.05) was found,but in PVP and TLP group,significant differences (F=6.892,P<0.01;F=7.802,P<0.01) among groups were observed.In addition,superior mesenteric artery group showed higher value of PVP and TLP than other methods.CONCLUSION: Lipo-PGE₁ obviously increases liver blood perfusion,especially for portal vein perfusion.Interventional technology provides an effective pathway to improve hepatic perfusion.