ABSTRACT
Objective To evaluate the role of extracellular signal-regulated kinase (ERK) signaling pathway in intrathecal dexmedetomidine-induced reduction of spinal cord ischemia-reperfusion (I/R)injury in rats.Methods Eighty clean-grade male Sprague-Dawley rats,aged 9-10 weeks,weighing 300-350 g,were divided into 4 groups (n =20 each) using a random number table method:sham operation group (group S),spinal cord I/R group (group I/R),dexmedetomidine group (group D),and dexmedetomidine plus ERK signaling pathway blocker PD98059 group (group P).Spinal cord ischemia was produced by cross-clamping of the abdominal aorta distal to the left renal artery for 25 min followed by reperfusion to establish the model of spinal cord I/R injury.Dexmedetomidine 1 μg/kg was intrathecally injected at 20 min before establishing the model in D and P groups,PD98059 2 mg/kg was given via the tail vein at the same time in group P,and the equal volume of normal saline was given instead in S and I/R groups.Five rats were selected at 6,8,10 and 12 h of reperfusion,and the modified Basso,Beattie,Bresnahan (BBB) scale was used to assess the hindlimb locomotor function.Five rats were sacrificed after assessing the locomotor function at 6 h of reperfusion,and the L3-5 segments of the spinal cord were taken for determination of cell apoptosis (by TUNEL) and expression of phosphorylated ERK (p-ERK) (by Western blot).The apoptosis index was calculated.Results Compared with group S,the BBB scores were significantly decreased at each time point of reperfusion,the apoptosis index was increased,and the expression of pERK was up-regulated in the other three groups (P＜0.05).Compared with I/R group,the BBB scores were significantly increased at each time point of reperfusion,the apoptosis index was increased,and the expression of p-ERK was up-regulated in group D,and no significant change was found in the apoptosis index or p-ERK expression in group P (P＞0.05).Compared with group D,the BBB scores were significantly decreased at each time point of reperfusion,the apoptosis index was increased,and the expression of pERK was down-regulated in group P (P＜0.05).Conclusion The mechanism by which intrathecal dexmedetomidine reduces spinal cord I/R injury is related to activating ERK signaling pathway in rats.
ABSTRACT
Objective@#To evaluate the role of extracellular signal-regulated kinase (ERK) signaling pathway in intrathecal dexmedetomidine-induced reduction of spinal cord ischemia-reperfusion (I/R) injury in rats.@*Methods@#Eighty clean-grade male Sprague-Dawley rats, aged 9-10 weeks, weighing 300-350 g, were divided into 4 groups (n=20 each) using a random number table method: sham operation group (group S), spinal cord I/R group (group I/R), dexmedetomidine group (group D), and dexmedetomidine plus ERK signaling pathway blocker PD98059 group (group P). Spinal cord ischemia was produced by cross-clamping of the abdominal aorta distal to the left renal artery for 25 min followed by reperfusion to establish the model of spinal cord I/R injury.Dexmedetomidine 1 μg/kg was intrathecally injected at 20 min before establishing the model in D and P groups, PD98059 2 mg/kg was given via the tail vein at the same time in group P, and the equal volume of normal saline was given instead in S and I/R groups.Five rats were selected at 6, 8, 10 and 12 h of reperfusion, and the modified Basso, Beattie, Bresnahan (BBB) scale was used to assess the hindlimb locomotor function.Five rats were sacrificed after assessing the locomotor function at 6 h of reperfusion, and the L3-5 segments of the spinal cord were taken for determination of cell apoptosis (by TUNEL) and expression of phosphorylated ERK (p-ERK) (by Western blot). The apoptosis index was calculated.@*Results@#Compared with group S, the BBB scores were significantly decreased at each time point of reperfusion, the apoptosis index was increased, and the expression of p-ERK was up-regulated in the other three groups (P<0.05). Compared with I/R group, the BBB scores were significantly increased at each time point of reperfusion, the apoptosis index was increased, and the expression of p-ERK was up-regulated in group D, and no significant change was found in the apoptosis index or p-ERK expression in group P (P>0.05). Compared with group D, the BBB scores were significantly decreased at each time point of reperfusion, the apoptosis index was increased, and the expression of p-ERK was down-regulated in group P (P<0.05).@*Conclusion@#The mechanism by which intrathecal dexmedetomidine reduces spinal cord I/R injury is related to activating ERK signaling pathway in rats.
ABSTRACT
Objective To observe the effect of sevoflurane and target controlled infusion (TCI)propofol on the oculocardiac reflex (OCR) in patients with paediatrie strabismus surgery.Methods One hundred and thirty-eight patients ASA Ⅰ-Ⅱ undergoing strabismus surgery were randomly allocated to six greups(propofol groups:P_1,P_2,P_3 group; sevoflurane groups:S_1,S_2,S_3 group,23 cases for each) according to target bispectral index (BIS) of 60,50 and 40.In propofol groups continuous infusion of propofolremifentanil [0.2μg/(kg·min)] was adjusted towards target BIS value.The sevoflurane-remffentanil [0.2μg/(kg·min) ] concentration with 50% N2O/O2 was adjusted toward target BIS too.The incidence of OCR and the lowest heart rate(HR) and BIS were recorded.Results The incidence of OCR were 73.9%(17/23),39.1%(9/23),17.4%(4/23),56.5%(13/23),26.1%(6/23),8.7%(2/23)in P_1,P_2,P_3,S_1,S_2,S_3 soup,P_2 and P_3 group were lower than P_1 group,S_2 and S_3 soup were lower than S_1 group,P_3,S_3,S_2,P_2 group were lower than S_1 and P_1 soup,S_1 soup was lower than P_1 group,S_2 soup was lower than P_2 group,S_3 group was lower than P_3 group,there was significant difference(P < 0.05 ).The densities of TCI propofol in P_2 and P_3 soup were higher than that in P_1 group [ (4.3 ±0.2),(5.5±0.1 ) mg/L vs (3.2±0.1 ) mg/L ] (P <0.05),and the densities of sevoflurane in S_2 and S_3 group were higher than that in S_1 group [ ( 1.8±0.3 )%,(2.3±0.2 )% vs(1.3±0.2 )% ] (P<0.05 ).The end-tidal concentration was different with difference of BIS too.Conclusions OCR is relevant to the depth of anesthesia.BIS values of 40-50 seem adequate for the inhibition of OCR.The results suggest that BIS may be a valuable tool during propofol-remifentanil or sevoflurane-remifentanil anesthesia for strabismus surgery in children.The incidence of OCR is higher in propofol than in sevoflurane at the same BIS.