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Objective To investigate the effects and mechanism of remifentanil on renal ischemia/reperfusion(IR) injury via mediating Fas apoptosis signal pathway in rats.Methods Sprague-Dawley rats were divided into 3 groups (n =20 each) by using the random number table method:sham operation group (S group),IR control group (IR group),experimental group (Rgroup).The renal IR model was prepared by clamping the bilateral renal arteries for 45 min followedby reperfusion in IR group and R group.In R group,remifentanil was infused at 1.0μg·kg-1 ·min-1 via the tail vein starting from 15 min before ischemia until 30 min of reperfusion.In S group and IR group,the same volume of physiological saline was given.At 15 min before ischemia and at 3 h,12 h,24 h of reperfusion,the renal tissue samples were obtained for detecting the apoptosis rate by flow cytometry,determining the level of Fas mRNA expression by RT-PCR,the level of caspase-8 and caspase-3 activation by Western blotting,and scoring the number of kidney tubules injury by Paller'method.Results In IR group,the renal tubular injury score,the apoptosis rate,the expression of Fas mRNA and the activation of caspase-3 in renal tissue increased at 3 h after reperfusion,and those continued to increase at 12 h after reperfusion and reached the peak at 24 h after reperfusion (P＜0.01),and the activity of caspase-8 increased at 3 b,reached the peak at 12 h after reperfusion and decreased at 24 h after reperfusion (P＜0.01).As compared with S group,the renal tubular injury score,apoptosis rate,the expression of Fas mRNA and the activation of caspase-3 at 3 h,12 h and 24 h of reperfusion and the activation of caspase-8 at 12 h,24 h of reperfusion were all increased in IR group and R group (P＜0.05 or 0.01).As compared with IR group,the renal tubular injury score,apoptosis rate,the expression of Fas mRNA and the activation of caspase-8 and caspase-3 at 3 h,12 h and 24 h of reperfusion were decreased in R group (P＜0.05 or 0.01).Conclusion Remifentanil inhibits cell apoptosis and alleviates renal IR damage by reducing the expression of Fas receptor and the activation of caspase-8 and caspase-3,and regulating the apoptotic signal pathway of Fas.
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Objective To evaluate the effect of remifentanil on Toll-like receptor 2 (TLR2) mRNA expression during renal ischemia-reperfusion (Ⅰ/R) in rats.Methods Fifty-four male Sprague-Dawley rats,weighing 200-250 g,were randomly divided into 3 groups (n=18 each) using a random number table:sham operation group (group S),Ⅰ/R group and remifentanil group (group R).Renal Ⅰ/R injury was produced by clamping the bilateral renal arteries for 45 min followed by reperfusion in Ⅰ/R and R groups.Bilateral renal arteries were only exposed but not clamped in group S.Remifentanil 1.0 μg · kg-1 · min-1 was infused via the tail vein starting from 15 min before ischemia until 30 min of reperfusion in group R,while the equal volume of normal saline was given instead in S and Ⅰ/R groups.The animals were sacrificed at 15 min before ischemia and 6 and 24 h of reperfusion,and the renal specimens were obtained for examination of the pathological changes (with light microscope) and for determination of the contents of tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) (by ELISA) and expression of TLR2 mRNA (by RT-PCR) and cell apoptosis (by double staining and flow eytometry).The apoptotic rate was calculated.Results Compared with group S,TLR2 mRNA expression was significantly up-regulated,and the contents of TNF-α and IL-6 and apoptotic rate were increased at 6 and 24 h of reperfusion in Ⅰ/R and R groups.Compared with group Ⅰ/R,TLR2 mRNA expression was significantly down-regulated,and the contents of TNF-α and IL-6 and apoptotic rate were decreased at 6 and 24 h of reperfusion in group R.The pathological changes were significantly attenuated in group R as compared with group Ⅰ/R.Conclusion The mechanism by which remifentanil reduces renal Ⅰ/R injury is related to down-regulation of TLR2 expression and decrease in TLR2 activity and inhibition of inflammatory responses in renal tissues and cell apoptosis in rats.
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Objective To investigate the effect of remifentanil on protein kinase C (PKC) activity during renal ischemia-reperfusion (I/R) in rats.Methods Seventy-five male Sprague-Dawley rats,weighing 250-300 g,were randomly divided into 5 groups (n=15 each) using a random number table:sham operation group (group S),I/R group,remifentanil group (group R),naloxone group (group N),and naloxone + remifentanil group (group NR).Renal ischemia was induced by clamping the bilateral renal arteries for 45 min using an atraumatic clamp followed by reperfusion.In R and NR groups,remifentanil 1.0 μg · kg-1 · min-1was infused via the caudal vein starting from 15 min before ischemia until 30 min of reperfusion.In N and NR groups,naloxone 0.3 mg/kg was injected via the caudal vein at 20 min before ischemia and 35 min of ischemia,respectively.The rats were sacrificed at 24 h of reperfusion and the kidneys were removed for determination of the ultrastructure of the renal tubular epithelial cells (using transmission electron microscope),activity of PKC in renal tissues (by ELISA),and expression of the PKC in renal tissues (by immuno-histochemistry).Results Compared with group S,the activity of PKC in renal tissues was significantly increased in the other four groups,and the expression of the PKC in renal tissues was up-regulated in group R.Compared with group I/R,the activity of PKC in renal tissues was significantlyincreased,the expression of PKC in renal tissues was up-regulated,and the pathological changes were attenuated in group R.Compared with group R,the activity of PKC in renal tissues was significantly decreased,the expression of PKC in renal tissues was down-regulated,and the pathological changes were aggravated in N and NR groups.Conclusion The mechanism by which remifentanil attenuates renal I/R injury may be related to up-regulation of PKC expression and increase in PKC activity through activating opioid receptors in rats.
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Objective To evaluate the effect of remifentanil on cell apoptosis during renal ischemia-reperfusion (I/R) in rats.Methods Seventy-five male Sprague-Dawley rats,weighing 220-250 g,were randomly divided into 3 groups (n =25 each):sham operation group (group S),I/R group,and remifentanil group (group R).Renal ischemia was induced by occlusion of the bilateral renal arteries for 45 min followed by reperfusion in groups I/R and R.Remifentanil was infused at 1.0 μg· kg-1 · min-1 via the caudal vein starting from 15 min before ischemia until 30 min of reperfusion in group R,while the equal volume of normal saline was given instead of remifentanil in groups S and I/R.At 15 min before ischemia (T0) and 3,6,12,24 h of reperfusion (T1-4),5rats were anesthetized and sacrificed,and renal specimens were obtained to detect the apoptotic rate and expression of Bax and Bcl-2 protein (by flow cytometry) and mRNA (by RT-PCR).The ratios between Bcl-2/Bax protein and mRNA expression were calculated.The pathological changes of renal tubules were scored.Results Compared with group S,the pathological scores and apoptotic rate were significantly increased at T1-4,and ratios between Bcl-2/Bax protein and mRNA expression were increased at T1,2,while decreased at T3,4 in groups R and I/R (P ＜0.01).Compared with group I/R,the pathological scores and apoptotic rate were significantly decreased at T1-4,while the ratios between Bcl-2/Bax protein and mRNA expression were increased in group R (P ＜ 0.05 or 0.01).Compared with the baseline value at T0,the pathological scores and apoptotic rates were significantly increased at T1 4,and the ratios of Bcl-2/Bax protein and mRNA expression were increased at T1,2,while decreased at T3,4 in groups R and I/R (P ＜ 0.01).Conclusion Regulation of Bcl-2/Bax expression and inhibition of cell apoptosis in renal tissues are involved in the mechanism by which remifentanil reduces renal I/R injury in rats.
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Objective To investigate the role of opioid receptors in remifentanil-induced attenuation of renal ischemia/reperfusion (I/R) injury in rats.Methods Seventy-five male Sprague-Dawley rats weighing 250-300 g were randomly divided into 5 groups ( n =15 each):sham operation group (group S),group I/R,remifentanil group (group R),naloxone group (group N),and naloxone + remifentanil group (group NR).Renal ischemia was induced by clamping the bilateral renal arteries for 45 min using an atraumatic clamp followed by reperfusion.In groups R and NR,remifentanil was infused at 1.0 μg· kg-1 · min-1 via the caudal vein starting from 15 min before ischemia until 30 min of reperfusion,while groups S,I/R and N received the equal volume of normal saline instead of remifentanil.In groups N and NR,naloxone 0.3 mg/kg was injected via the caudal vein at 20 min before ischemia and at 35 min after ischemia respectively,while groups S,I/R and R received the equal volume of normal saline instead of naloxone.Blood and urine samples were collected from the femoral vein and urinary bladder respectively at 24 h of reperfusion for determination of the levels of serum creatinine (Cr) and blood urea nitrogen (BUN),urinary N-acetyl-β-D-glucosaminidase (NAG) and γ-glutamyl transpeptidase (γ-GT).The rats were sacrificed at 24 h of reperfusion and the renal tissues were removed for determination of nalondialdehyde (MDA) content and superoxide dismutase (SOD) activity.Pathological changes in renal tissues were observed with light microscope.Results Compared withgroup S,the levels of serum Cr and BUN,urinary NAG and γ-GT,and MDA were significantly increased,while the activity of SOD was significantly decreased in the other 4 groups ( P ＜ 0.05 or 0.01 ) and pathological changes in renal tissues were observed in the other 4 groups.Compared with group I/R,the levels of serum Cr and BUN,urinary NAG and γ-GT levels,and MDA were significantly decreased,while the activity of SOD was significantly increased ( P ＜ 0.01 ),and the pathological changes were reduced in group R,and no significant change was found in the parameters mentioned above in groups N and NR ( P ＞ 0.05).The pathological changes were similar in groups I/R,N and NR.Compured with group R,serum Cr and BUN concentrations,urinary NAG and γ-GT levels and MDA concent were increased,while SOD activity were decreased ( P ＜ 0.05 or 0.01 ).Conclusion Opioid receptors mediate remifentanil-induced attenuation of renal I/R injury in rats.
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Objective To investigate the effect of remifentanil on nucleotide-binding oligomerization domain 1 (NOD1) mRNA expression in rats with renal ischemia-reperfusion (I/R) injury.Methods Sixty male Sprague-Dawley rats,weighing 220-250 g,were randomly divided into 3 groups (n =20 each):sham operation group (S group),I/R group and remifentanil group (R group).Renal ischemia was induced by occlusion of bilateral renal arteries for 45 min followed by 24 h reperfusion in groups I/R and R.Remifentanil 1.0 μg· kg-1 · min-1 was infused until 30 min of reperfusion starting from 15 min before ischemia in group R,while the equal volume of normal saline was given instead in S and I/R groups.The animals were sacrificed at 15 min before ischemia and at 3,6,24 h of reperfusion and the kidneys were removed for microscopic examination and polymorphonuclear leukocyte (PMN) count and for measurement of NOD1 mRNA expression (by RT-PCR).The apoptotic rate was determined by flow cytometry double staining method.Results Compared with group S,NOD1 mRNA expression was up-regulated,and the apoptotic rate and PMN count were significantly increased at each time point during reperfusion in group I/R,and the apoptotic rate and PMN count were significantly increased at each time point during reperfusion,and NOD1 mRNA expression was up-regulated at 6 and 24 h of reperfusion in group R (P ＜ 0.01).Compared with I/R group,NOD1 mRNA expression was down-regulated,and the apoptotic rate and PMN count were significantly decreased at each time point during reperfusion (P ＜ 0.05 or 0.01),and the pathological changes were significantly attenuated in group R.Conclusion Remifentanil can reduce the renal I/R injury by down-regulating the expression of NOD1 mRNA and inhibiting inflammatory response and apoptosis.