Objective To investigate the effect of intrathecal γ-aminobutyric acid transporter-1 ( GAT-1 )small interfering RNA (siRNA) on neuropathic pain in rats. Methods Male SD rats weighing 200-250 g were studied. The experiment was performed in 3 parts. Part Ⅰ Twenty rats were randomly divided into 5 groups ( n =4 each): GAT-1 siRNA-1 group, GAT-1 siRNA-2 group, GAT-1 siRNA-3 group, negative control siRNA group and DEPC treatment group. Two days after ligation of sciatic nerve, intrathecal siRNA 2 μg or equal volume of DF-PC was injected once a day for 3 consecutive days. The rats were killed and the lumbar segment of the spinal cord was removed at 2nd day after the last intrathecal injection for determination of the expression of GAT-1 in the spinal dorsal horn by Western Blot. Part Ⅱ Thirty rats were randomly divided into 3 groups ( n = 10 each): GAT-1 siRNA-3 + lipo2000 group, GAT-1 siRNA-3 mismatch siRNA + lipo2000 group, and DEPC treatment + lipo2000group. Paw-withdrawl threshold (PWT) to thermal and mechanical stimulation was measured before ligation of sciatic nerve, 3 days after ligation of sciatic nerve and at 1, 3, 5, 7 and 10 days after consecutive administration for 3 days. Part Ⅲ Eighty-four rats were randomly divided into 3 groups as described in Part Ⅱ ( n = 28 each). Four rats were killed at each time point and the lumbar segment of the spinal cord was removed for determination of the expression of GAT-1 in the spinal dorsal horn by Western blot. Results PWT to thermal and mechanical stimulation was significantly inreased and the GAT-1 expression was down-regulated after the injection of GAT-1 siRNA.Conclusion Intrathecal GAT-1 siRNA can reduce the neuropathic pain by inhibiton of up-regulation of the GAT-1 expression in the spinal dorsal horn in rats.

Objective To investigate the glial activation in the spinal cord in a rat model of persistent postoperative pain. Methods Forty-eight adult male SD rats weighing 200-250 g were randomly divided into 2 groups ( n = 24 each): group Ⅰ sham operation (group S) and group Ⅱ persistent postoperative pain. Persistent postoperative pain was evoked by skin/muscle incision and retraction (SMIR) as described by Flatters. Pawwithdrawal threshold to yon Frey hair stimulation was measured before operation (baseline) and at 1, 3, 12, 22and 32 d after establishment of the model. Four animals were sacrificed at each time point and lumbar segment of the spinal cord was removed for determination of expression of glial fibrillary acidic protein (GFAP) in the astrocytes by immunofluorescence histo-chemistry assay. Results The mechanical threshold started to decrease at 1 d after establishment of the model, and peaked at 12 d after establishment of the mode. Immunofluorescence histochemistry assay demonstrated that GFAP expression in the dorsal horn was significantly increased at 3 d after estabhshment of the model and reached the peak at 12 d and was maintained at the high level until 22 d after establishment of the model. Conclusion Glial activation is involved in the mechanism of persistent postoperative pain evoked by SMIR.

Objective To investigate the role of microglial activation in spinal cord in a rat model of persistent postoperative pain evoked by skin/muscle incision and retraction (SMIR) .Methods Seventy-two male SD rats weighing 200-250 g in which intrathecal (IT) catheter was successfully inserted were randomly divided into 3 groups ( n = 24 each) : group sham operation; group SMIR and group SMIR + FT minocycline (a specific microglia inhibitor) . The rat model of persistent postoperative pain evoked by SMIR was established according to the method described by Flatters. Pain behavior was assessed by paw mechanical withdrawal threshold ( MWT) to von Frey filament stimulation at 1 day before (T0,baseline) and 3, 7, 12, 22 and 32 days after operation (T1-5,) . Four animals were sacrificed at each time point in each group for detection of the expression of Iba-1 (a specific marker of microglia) in the spinal dorsal horn by immunofluorescence and the microglia was counted. Results MWT was significantly decreasedat T1-4, while the expression of Iba-1 and microglia counts in the spinal dorsal horn were significantly increased at T1, 2 by SMIR in group Ⅱ. IT minocycline significantly attenuated the hyperalgesia induced by SMIR at T1-4 and decreased Iba-1 expression and microglia counts at T1,2 in group Ⅲ. Conclusion Microglial activation in the spinal cord plays an important role in the development and maintenance of SMIR-evoked persistent postoperative pain in rats.

Objective To investigate the role of gamma-aminobutyric acid transporter-1 (GAT-1) in the spinal cord in a rat model of bone cancer pain.Methods Eighty female SD rats weighing 150-180 g were randomly divided into 5 groups (n =16 each): sham operation group(group Ⅰ ),bone cancer pain group(group Ⅲ ),sham operation+ NO-711 group(group Ⅲ ),Ⅳ group BCP + NO-711 group(group Ⅳ ) and BCP + vehicle group (group Ⅴ ).Bone cancer pain was induced by inoculating Walker-256 mammary gland carcinoma cells into medullary cavity of tibia.NO-711 (20 μg,10 μl) was administered intrathecally once a day for 3 consecutive days from the 14th day after operation.Mechanical withdrawl threshold (MWT) of mechanical stimulus was determined the day before operation and at days 3,5,7,10,14 and 16 after operation.The animals were sacrificed on the 16th day after operation,and then the spinal cords were removed for determination of the expression of GAT-1 and double immunostaining of GAT-1 and glial fibrillary acidic protein (GFAP,astrocyte marker).Results MWT were significantly decreased in groups Ⅱ,Ⅳ and Ⅴ as compared with groups.Ⅰ and Ⅲ.The expression of GAT-1 significantly up-regulated in groups Ⅱ,Ⅴ as compared with groups Ⅰ and Ⅲ.NO-711 significantly increased MWT,while decreased the expression of GAT-1 in group Ⅳ compared with groups Ⅱ and Ⅴ.The expression of GAT-1 up-regulation appeared colocalizes with in astrocytes activation in spinal dorsal horn.Conclusion The up-regulation of expression of GAT-1 in spinal cord is involued in the development and maintenance of bone cancer pain,which may be related to the astrocytes activation.

Objective It has been shown that protein kinase C (PKC), especially PKCy is involved in the nociceptive processing at the spinal level. This study was designed to investigate the effects of intrathecal (IT) morphine on PKCy immuno-reactivity in the spinal dorsal horn in a rat model of incisional pain. Methods Twenty-four male SD rats weighing 250-300 g were anesthetized with intraperitoneal pentobarbital 40 mg?kg-1. PE-10 catheter was inserted intrathecally to the lumbar region according to Yaksh. Five days later an incision of 1cm long was made in the plantar region of left hindpaw, parallel to the muscle under isoflurane anesthesia according to Brennan. The animals were randomly divided into 4 groups with 6 animals in each group : group Ⅰ sham-operation group received IT artificial cerebro-spinal fluid (ACSF) 20 ?l and 30 min later inhaled 1.4% isoflurane for S min but no incision was made; group Ⅱ received ACSF 20 ?l IT 30 min before incision was made; group Ⅲ post-incisional morphine group received morphine 5 ?g IT 30 min after incision and group Ⅳ pre-incisional morphine group received morphine 5 ?g IT 30 min before incision. The animals were sacrificed under general anesthesia 2 h after incision. The L4-5 segment of spinal cord was removed for determination of the expression of PKC? in the spinal dorsal horn by immuno-histochemical method.Results In group Ⅱ the PKC?-IR gray density in the spinal dorsal horn of the operated side was significantly higher than that of contralateral side and that in group Ⅰ( P

0.05) compared to control group. Conclusion Induction of anesthesia with isoflurane or enflurane decreases the number of NOS positive neurons in the 6 nuclei in limbic system. The changes in NOS positive neurons in limbic system may be involved in the mechanism of isoflurane and enflurane anesthesia.

Objective To investigate the effect of hypothermia on cytokine expression in rats with lipopolysaccharide- induced acute respiratory distress syndrome (ARDS), and investigate whether or not hypothermia can inhibit inflammatory reaction and attenuated lung injuries, thereby preventing the development of ARDS. Methods A rat model of ARDS was established by intratracheal instillation of lipopolysaccharide (3 mg/ kg, 0.5 ml, LPS) at 16 h after LPS (1 mg/kg, 0.3 ml) intraperitoneal administration. Thirty-two male Sprague Dawley rats were randomly divided into four groups: ARDS + Normalthermia (AN) , ARDS + Hypothermia (AH) , NS+ Normalthermia (NN), and NS + Hypothermia (NH) groups. At 3 h after ARDS, rats were killed by hemorrhage from carotid artery. Lung lavage was performed, tumor necrosis factor ?(TNF-?) , interleukin-6 (IL-6) concentrations in BALF were measured using enzyme-linked immunosorbent assay (ELISA) .Results Within (2.3?1.6) h the ARDS model in AN group and AH group was successfully replicated. Compared with the NN group, the concentrations of TNF-? and IL-6 increased significantly in the AN group ( P 0.05). Conclusion Hypothermia has inhibitory effect on the expression and release of the pro-inflammatory cytokine (TNF-?, IL-6) in rats with ARDS. Hypothermia may inhibit inflammatory reaction, attenuated lung injuries and serve as a new measure to prevent and treat ARDS.

Aim To explore the effect of propofol preconditioning on cardiocyte apoptosis and cytochrome C release from mitochondria during hypoxia/reoxygenation in isolated rat hearts.Methods Fifty male Sprague-Dawley rats weighing 250～300 g were randomly divided into 5 groups(n=10 each):control group(C);Dimethyl sulfoxide(DMSO)preconditioning group(D);3 propofol preconditioning groups with 25 ?mol?L-1(P1)、50 ?mol?L-1(P2)、100 ?mol?L-1(P3)propofol respectively.The isolated rat hearts were retrogradely perfused via aorta with K-H solution on Langendorff apparatus.The isolated hearts were made hypoxia for 30 minutes followed by 60 minutes reoxygenation in each group.The D,P1,P2,P3 groups were preconditioned by perfusing 10 min K-H solution containing 20 ?mol?L-1 DMSO and 25,50,100 ?mol?L-1 propofol respectively and then followed by 5 min K-H solution reperfusion before hypoxia.The preconditioning procedure was repeated twice.The cardiac functional variables were recorded after equilibration(baseline values),immediately before hypoxia,at the end of 30 min and 60 min reoxygenation.Apoptotic myocardial cells were detected by terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling(TUNEL)and the level of cytochrome C expression in myocardial cytosol and mitochondria was measured by Western blot at the end of reoxygenation.Results At the end of 30 min and 60 min reoxygenation,LVEDP was significantly lower and LVDP was significantly higher in P1,P2,P3 groups than in D group(P

To investigate the effects of ketamine on nitric oxide synathase(NOS)activity, nitrc oxide (NO) output and cyclic guanosine 3', 5'-monophosphate(cGMP)content in the rat brain. Method: Thirty two SD rats were divided randomly into control group and ketamine group. The aminals were administred intraperitoneally(ip)normal saline 10mg?kg~(-1) or ketamine 100mg?kg~(-1), respectively. NOS activity and NO output were assassed with spectrophotometric analysis, cGMP content was measured with radioimmunoassay, Result: Ketamine 100mg?kg~(-1) ip significantly inhibited NOS activity(P

Tn investigate the effects of propofol on Ca~(2+) ATPase activity in rat cerebral synaptic membrane. Method: Thirty SD rats were divided randomly into three groups. The aminals were administtered introperi toneally(ip) propofol 50mg?kg~(-1), 100mg?kg~(-1) or normal saline 10mg?kg~(-1)(control group), respectively. These rats were immediately decapitated after having disappeared righting reflex. In oredr to prepare synaptosomes, brain tissues were dissected on ice, then homogenized and centrifuged. Ca~(2+)-ATPase activity was assaed with spcetrophotometric analysis. Result: Propofol 100mg?kg~(-1) ip significantly inhibited Ca~(2+)-ATPase activity of cerebrocortical, brain stems and hippocampal synaptic membrane as compared with that of normal saline group(P