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Objective:To evaluate the role of secreted protein acidic and rich in cysteine like protein 1 (SPARCL1) in spinal dorsal horns in the development of remifentanil-induced hyperalgesia in mice with incisional pain.Methods:Forty-eight healthy male C57BL/6J mice, aged 8-10 weeks, weighing 18-22 g, were divided into 6 groups ( n=8 each) using a random number table method: control group (group C), incisional pain group (group I), remifentanil group (group R), incisional pain plus remifentanil group (group I+ R), incisional pain plus remifentanil plus negative control group (group I+ R+ N), and incisional pain plus remifentanil plus SPARCL1-siRNA group (group I+ R+ S). In I+ R+ N and I+ R+ S groups, 1×10 8 IFU/ml negative control siRNA and SPARCL1-siRNA 10 μl were intrathecally injected, respectively, once a day for 3 consecutive days.Normal saline 10 μl was intrathecally injected once a day for 3 consecutive days in C, I, R and I+ R groups.After transfection was stable, normal saline 0.1 ml was intravenously injected through the tail vein for 4 consecutive times at 15 min interval in C and I groups, and remifentanil 10 μg/kg (diluted to 0.1 ml in normal saline) was intravenously injected via the tail vein for 4 consecutive times at 15 min interval in R, I+ R, I+ R+ N and I+ R+ S groups.The incisional pain model was established after the first administration via the tail vein in R, I+ R, I+ R+ N and I+ R+ S groups.The mechanical paw withdrawal threshold (MWT) and thermal paw withdrawal latency (TWL) were measured at 24 h before infusing normal saline or remifentanil (T 0) and 3, 6, 24 and 48 h after stopping infusion (T 1-4). Animals were sacrificed after measuring pain threshold at T 4, and L 4-6 segments of the spinal cord were removed for determination of the expression of SPARCL1 protein and mRNA by Western blot and quantitative real-time polymerase chain reaction, respectively. Results:Compared with group C, MWT was significantly decreased and TWL was shortened at T 1-4 in I+ R and I+ R+ N groups and at T 2-4 in I, R and I+ R+ S groups, and the expression of SPARCL1 protein and mRNA was significantly up-regulated in R, I+ R and I+ R+ C groups ( P<0.05 or 0.01). Compared with group I and group R, MWT was significantly decreased, TWL was shortened, and the expression of SPARCL1 protein and mRNA was up-regulated in group I+ R ( P<0.01). Compared with group I+ R, MWT was significantly increased and TWL was prolonged at T 1-4, and the expression of SPARCL1 protein and mRNA was down-regulated in group I+ R+ S ( P<0.05 or 0.01). Conclusion:Enhanced activity of SPARCL1 in the spinal dorsal horns is involved in the development of remifentanil-induced hyperalgesia in mice with incisional pain.
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Objective@#To evaluate the role of spinal COX-1 and COX-2 in remifentanil-induced hyperalgesia in mice with incisional pain.@*Methods@#Thirty-two male C57BL/6J mice, aged 8-10 weeks, weighing 20-25 g, were divided into 4 groups (n=8 each) using a random number table method: control group (group C), incisional pain plus remifentanil group (group IR), incisional pain plus remifentanil plus selective COX-1 inhibitor group (group IR+ SC560), and incisional pain plus remifentanil plus selective COX-2 inhibitor group (group IR+ SC236). In IR, IR+ SC560 and IR+ SC236 groups, normal saline 10 μl, SC560 25 μg and SC236 25 μg were intrathecally injected, respectively, 15 min later remifentanil 10 μg/kg was injected via the tail vein for 4 times at 15 min intervals.An incisional pain model was established after the first injection of remifentanil.The mechanical paw withdrawal threshold (MWT) was measured at 24 h before normal saline or remifentanil injection and 3, 6, 24 and 48 h after the last injection (T0-T4). The mice were sacrificed after the last measurement of pain threshold, and the L4-6 segments of the spinal cord were removed for determination of the expression of COX-1 and COX-2 (by Western blot) and expression of COX-1 and COX-2 mRNA (by quantitative real-time polymerase chain reaction).@*Results@#Compared with group C, the MWT was significantly decreased, and the expression of COX-2 protein and mRNA was up-regulated in IR, IR+ SC560 and IR+ SC236 groups (P<0.05). Compared with group IR, the MWT was significantly increased in IR+ SC560 and IR+ SC236 groups (P<0.05). There was no significant difference in the MWT at each time point between IR+ SC560 and IR+ SC236 (P>0.05) .There was no significant difference in the expression of COX-2 protein and mRNA among group IR, group IR+ SC560 and group IR+ SC236 (P>0.05). There was no significant difference in the expression of COX-1 protein and mRNA among the four groups (P>0.05).@*Conclusion@#Compared with COX-1, spinal COX-2 plays a major role in the pathophysiological mechanism of remifentanil-induced hyperalgesia in mice with incisional pain.
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Objective To evaluate the role of spinal COX-1 and COX-2 in remifentanil-induced hyperalgesia in mice with incisional pain.Methods Thirty-two male C57BL/6J mice,aged 8-10 weeks,weighing 20-25 g,were divided into 4 groups (n =8 each) using a random number table method:control group (group C),incisional pain plus remifentanil group (group IR),incisional pain plus remifentanil plus selective COX-1 inhibitor group (group IR+SC560),and incisional pain plus remifentanil plus selective COX-2 inhibitor group (group IR+SC236).In IR,IR+SC560 and IR+SC236 groups,normal saline 10 μl,SC560 25 μg and SC236 25 μg were intrathecally injected,respectively,15 min later remifentanil 10 μg/kg was injected via the tail vein for 4 times at 15 min intervals.An incisional pain model was established after the first injection of remifentanil.The mechanical paw withdrawal threshold (MWT) was measured at 24 h before normal saline or remifentanil injection and 3,6,24 and 48 h after the last injection (T0-T4).The mice were sacrificed after the last measurement of pain threshold,and the L4-6 segments of the spinal cord were removed for determination of the expression of COX-1 and COX-2 (by Western blot)and expression of COX-1 and COX-2 mRNA (by quantitative real-time polymerase chain reaction).Results Compared with group C,the MWT was significantly decreased,and the expression of COX-2 protein and mRNA was up-regulated in IR,IR+SC560 and IR+SC236 groups (P＜0.05).Compared with group IR,the MWT was significantly increased in IR+SC560 and IR+SC236 groups (P＜0.05).There was no significant difference in the MWT at each time point between IR+SC560 and IR+SC236 (P＞0.05).There was no significant difference in the expression of COX-2 protein and mRNA among group IR,group IR+SC560 and group IR+SC236 (P＞0.05).There was no significant difference in the expression of COX-1 protein and mRNA among the four groups (P＞0.05).Conclusion Compared with COX-1,spinal COX-2 plays a major role in the pathophysiological mechanism of remifentanil-induced hyperalgesia in mice with incisional pain.
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Objective To evaluate the role of neuroligin 1 (NL-1) in trafficking of GluR1-containing AMPA receptor to cell membrane in spinal cord dorsal horns during remifentanil-induced hyperalgesia in mice with incisional pain.Methods Forty SPF healthy male C57BL/6J mice,aged 8-10 weeks,weighing 18-22 g,were divided into 5 groups (n=8 each) using a random number table method:control group (group C),NL1-shRNA plasmid group (group NL),incisional pain plus remifentanil group (group I+R),incisional pain plus remifentanil plus blank vector group (group I+R+B),and incisional pain plus remifentanil plus NL-1-shRNA plasmid group (group I+R+NL).Negative lentivirus was intrathecally injected in group I+R+B.In NL and I+R+NL groups,10 μl NL-1-shRNA lentivirus at 1×10s IFU/ml was intrathecally injected once a day for 3 consecutive days.Normal saline 10 μl was intrathecally injected at the same time point in C and I+R groups.After transfection was stable,normal saline 0.1 ml was injected via the caudal vein for 4 consecutive times at 15 min intervals in C and NL groups.In I+R,I+R+B and I+R+NL groups,0.1 ml remifentanil 10 μg/kg was injected via the caudal vein for 4 consecutive times at 15 min intervals,and the model of incisional pain was established after the first administration.The mechanical paw withdrawal threshold (MWT) and tail-flick latency (TFL) were measured at 24 h before normal saline or remifentanil administration (T0) and at 3,6,24 and 48 h after the end of administration (T1-4).The animals were sacrificed after measurement of pain threshold at T4,and L4-6 segments of the spinal dorsal horn were then collected for determination of the expression of NL-1 protein and mRNA and AMPA receptors,and the ratio of AMPA receptor expression in the membrane protein to that in the total protein (m/t ratio) was calculated.Results Compared with group C,the MWT was significantly decreased,and TFL was shortened at T1-4,the expression of NL-1 protein and mRNA and GluR1-containing AMPA receptors in membrane and total proteins was up-regulated,and m/t ratio was increased in I+R and I+R+B groups (P＜0.05).Compared with I+R and I+R+B groups,the MWT was significantly increased and TFL was prolonged at T1-4,the expression of NL-1 protein and mRNA and GluR1-containing AMPA receptors in membrane and total proteins was down-regulated,and m/t ratio was decreased in group I+R+NL (P＜0.05).Conclusion NL-1 in spinal cord dorsal horns can promote the trafficking of GluR1-containing AMPA receptors to cell membrane,which is involved in the development and maintenance of remifentanil-induced hyperalgesia in mice with incisional pain.
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Objective@#To evaluate the role of neuroligin 1 (NL-1) in trafficking of GluR1-containing AMPA receptor to cell membrane in spinal cord dorsal horns during remifentanil-induced hyperalgesia in mice with incisional pain.@*Methods@#Forty SPF healthy male C57BL/6J mice, aged 8-10 weeks, weighing 18-22 g, were divided into 5 groups (n=8 each) using a random number table method: control group (group C), NL1-shRNA plasmid group (group NL), incisional pain plus remifentanil group (group I+ R), incisional pain plus remifentanil plus blank vector group (group I+ R+ B), and incisional pain plus remifentanil plus NL-1-shRNA plasmid group (group I+ R+ NL). Negative lentivirus was intrathecally injected in group I+ R+ B.In NL and I+ R+ NL groups, 10 μl NL-1-shRNA lentivirus at 1×108 IFU/ml was intrathecally injected once a day for 3 consecutive days.Normal saline 10 μl was intrathecally injected at the same time point in C and I+ R groups.After transfection was stable, normal saline 0.1 ml was injected via the caudal vein for 4 consecutive times at 15 min intervals in C and NL groups.In I+ R, I+ R+ B and I+ R+ NL groups, 0.1 ml remifentanil 10 μg/kg was injected via the caudal vein for 4 consecutive times at 15 min intervals, and the model of incisional pain was established after the first administration.The mechanical paw withdrawal threshold (MWT) and tail-flick latency (TFL) were measured at 24 h before normal saline or remifentanil administration (T0) and at 3, 6, 24 and 48 h after the end of administration (T1-4). The animals were sacrificed after measurement of pain threshold at T4, and L4-6 segments of the spinal dorsal horn were then collected for determination of the expression of NL-1 protein and mRNA and AMPA receptors, and the ratio of AMPA receptor expression in the membrane protein to that in the total protein (m/t ratio) was calculated.@*Results@#Compared with group C, the MWT was significantly decreased, and TFL was shortened at T1-4, the expression of NL-1 protein and mRNA and GluR1-containing AMPA receptors in membrane and total proteins was up-regulated, and m/t ratio was increased in I+ R and I+ R+ B groups (P<0.05). Compared with I+ R and I+ R+ B groups, the MWT was significantly increased and TFL was prolonged at T1-4, the expression of NL-1 protein and mRNA and GluR1-containing AMPA receptors in membrane and total proteins was down-regulated, and m/t ratio was decreased in group I+ R+ NL (P<0.05).@*Conclusion@#NL-1 in spinal cord dorsal horns can promote the trafficking of GluR1-containing AMPA receptors to cell membrane, which is involved in the development and maintenance of remifentanil-induced hyperalgesia in mice with incisional pain.