| Part 1 Effect of nitrotyrosine on (-adrenoceptor mediated vascular reactivity in ratsObjective: To observe the effect of 3–nitrotyrosine (3–NT) on (-adrenoceptor mediated vascular reactivity in rats and investigate its possible mechanism.Methods: Male SD rats were randomly divided into 2 groups: the control group (intravenous administration of saline, n = 12), and the 3–NT group (intravenous administration of 3 - NT 2.5 (mol · kg-1, n=12). After 30 minutes and 90 minutes, apply phenylephrine (0.5 - 2.5 (g · kg-1) or vasopressin(1.3 - 5.2 (g · kg-1)intravenously to both groups and record the percentage increased in MAP, respectively. The rings of aorta from another set of healthy rats were incubated for 2h in Krebs- Ringer buffer, concentration-response curve were obtained by cumulative addition of PE (10-9 - 3 (10-5 mol · L-1). After five washes, again divide the samples into the repeat control group (Krebs-Ringer Solution) and the 3-NT group (Krebs-Ringer Solution with 250 (mol · L-1 3 - NT). After 60 minutes of incubation, reapply PE to both groups and record the response of tissue.Results Compared with control group, application of 3-NT (2.5 (mol · kg-1)significantly inhibited the MAP increase induced by phenylephrine with time-dependent way, but it did not affect the MAP level induced by vasopressin. In the vascular tension experiment, no significant differences were observed between the control group and 3-NT group in dose-response curve, Emax and EC50 values to PE.Conclusion 3-NT selectively attenuated (-adrenoceptor-mediated the hemodynamic responses, but this property is not related to the competitive antagonise (1-adrenoceptor, indicated that 3-NT may affect the the vascular reactivity through other mechanisms. Part 2 Effect of nitrotyrosine on the expression of (1D-adrenoceptorin smooth muscle cellObject:To investigate the effect of nitrotyrosine(3 - NT) on the expression of (1D-adrenoceptor ((1D - AR). Methods:Each smooth muscle cell(SMC) primary culture was obtained from thoracic aorta media from 1 month rats.Then the whole cell was divided into two groups:concentration group(0,1,10,100,200 umol · L-1 3 - NT intervented the SMC for 24 h individually) and time group(100 umol · L-1 3 - NT intervented the SMC for 0,12,24,48,72h individually).We use reverse transcription polymerase chain reaction to measure the mRNA expression of (1D-AR in cultured SMC.Results:The expression of (1D-AR mRNA in SMC decreased gradually by the increasing concentration of 3 - NT intervention.The maximum descend was reached to 28.8% compared with the control.(P < 0.05).Morever, the expression of (1D-AR mRNA in time group decreased gradually by the increasing time of 3-NT. intervention as well as the concentration group. In time group, (1D-AR mRNA reached the lowest at 48 h, which reduced to 34.9% contrasted to the control.(P < 0.05). Conclusion:3 - NT inhibits the expression of (1D-AR mRNA by concentration and time –dependent method. It maybe a new pathway to cause the vascular hyporeactivity in septic shock.Part 3 Therapeutic effect and possible mechanism of the antioxidants on vascular hyporeactivity of rats in endotoxin-induced septic shockObjective:To observe the therapeutic effects of propofol,uric acid and melatonin on vascular hyporeactivity of rat in septic shock and its possible mechanism.Methods:Fifty SD rats were randomly divided into five groups:1.the control group(n = 10);2.septic shock group(n = 10):intravenous administration of LPS 15mg· kg-1;3.propofol treated group(n = 10):1h after LPS administration,intravenous administration of propofol 10mg · kg-1 then supplementary continuous infusion of propofol 10mg· kg-1.h-1; 4.uric acid treated group:1h after LPS administration, intraperitoneal administration of uric acid 200mg· kg-1,( n = 10).5.positive control groups:melatonin treated group(1h after LPS administration, 10mg· kg-1 given intraperitoneally,n = 10), 6h after septic shock, apply phenylephrine (PE, 0.5 ～ 2.5 (g· kg-1) intravenously to all gr...
|
PDF Full Text Request