Preoperative sleep loss can amplify post-operative mechanical hyperalgesia. However, the underlying mechanisms are still largely unknown. In the current study, rats were randomly allocated to a control group and an acute sleep deprivation (ASD) group which experienced 6 h ASD before surgery. Then the variations in cerebral function and activity were investigated with multi-modal techniques, such as nuclear magnetic resonance, functional magnetic resonance imaging, c-Fos immunofluorescence, and electrophysiology. The results indicated that ASD induced hyperalgesia, and the metabolic kinetics were remarkably decreased in the striatum and midbrain. The functional connectivity (FC) between the nucleus accumbens (NAc, a subregion of the ventral striatum) and the ventrolateral periaqueductal gray (vLPAG) was significantly reduced, and the c-Fos expression in the NAc and the vLPAG was suppressed. Furthermore, the electrophysiological recordings demonstrated that both the neuronal activity in the NAc and the vLPAG, and the coherence of the NAc-vLPAG were suppressed in both resting and task states. This study showed that neuronal activity in the NAc and the vLPAG were weakened and the FC between the NAc and the vLPAG was also suppressed in rats with ASD-induced hyperalgesia. This study highlights the importance of preoperative sleep management for surgical patients.
Rats ; Animals ; Hyperalgesia/metabolism* ; Sleep Deprivation/metabolism* ; Rats, Sprague-Dawley ; Periaqueductal Gray/pathology* ; Proto-Oncogene Proteins c-fos/metabolism* ; Pain, Postoperative/pathology*

Objective:To investigate the role of PI3K/Akt signaling pathway in hydromorphone postconditioning on alleviating myocardial ischemia/reperfusion (I/R)-induced apoptosis in rats.Methods:Forty healthy male SD rats were randomly(random number) divided into five groups, with 8 rats in each group:①sham group;②I/R group;③I/R+hydromorphone group (I/R+H group);④I/R+PI3K inhibitor group (I/R+W group); and⑤I/R+hydromorphone+PI3K inhibitor group (I/R+H+W group). The myocardial ischemia/reperfusion injury model was established by ligating the left anterior descending coronary artery for 30 min and reperfusion for 120 min. After the experiment, the area of myocardial infarction was measured by 2, 3, 5-triphenyl tetrazolium chloride (TTC) staining. The amount of serum lactate dehydrogenase (LDH) leakage was estimated by colorimetry . The cardiomyocyte apoptosis was detected by terminal deoxynucleotidyl transferase mediated dUTP nick-end labeling (TUNEL) assay. The protein expressions of p-Akt, Bcl-2 and Bax were detected by Western blot. Comparisons among groups were carried out by analysis of variance (ANOVA).Results:Compared with the sham group, the area of myocardial infarction, serum LDH leakage and cardiomyocyte apoptosis were significantly increased, p-Akt and Bax expression were upregulated, Bcl-2 expression was downregulated in the I/R group ( P<0.05). Compared with the I/R group, the area of myocardial infarction, serum LDH leakage and cardiomyocyte apoptosis were markedly decreased, p-Akt and Bcl-2 expression were upregulated and Bax expression was downregulated in the I/R+H group ( P<0.05). Compared with the I/R+H group, the area of myocardial infarction, serum LDH leakage and cardiomyocyte apoptosis were significantly increased, p-Akt and Bcl-2 expression were downregulated, and Bax expression was upregulated in the I/R+H+W group ( P<0.05). Conclusions:Hydromorphone postconditioning can alleviate cardiomyocyte apoptosis induced by myocardial ischemia/reperfusion, and its protection mechanism may be related to the activation of PI3K/Akt signaling pathway.

Objective:To evaluate the relationship between the over-expression of endocannabinoid receptor 2 (CB2R) and macrophage pyroptosis in mice.Methods:Bone marrow-derived macrophages of mice were transfected by lentivirus vector and successfully screened out two stable cell lines: lentivirus LV5 negative control cells (LV5-NC) and lentivirus LV5CB2R overexpressing cells (OE). Two cell lines were respectively divided into 3 groups ( n=18 each) using a random number table method: control group (LV5-NC-C group, OE-C group), LPS/ATP group (LV5-NC-LPS/ATP group, OE-LPS/ATP group) and CB2R specific agonist HU308 group (LV5-NC-HU308 group, OE-HU308 group). Cells in group C were commonly cultured.In LPS/ATP group, cells were incubated with LPS at a final concentration of 0.5 μg/ml for 5 h, and then incubated with ATP at the final concentration of 5 mmol/L for 1 h. In group LPS/ATP+ HU308, cells were incubated for 5 h with LPS at the final concentration of 0.5 μg/ml and HU308 at the final concentration of 10 μmol/L and then with ATP at the final concentration of 5 mmol/L for 1 h. The expression of CB2R, nucleotide-binding oligomerization domain-like receptor containing pyrin domain 3 (NLRP3), caspase-1, and gasdermin D (GSDMD) mRNA was detected by real-time polymerase chain reaction, the expression of caspase-1 was detected by Western blot, and the concentrations of interleukin-18 (IL-18) and IL-1β in the culture medium were determined by enzyme-linked immunosorbent assay. Results:In each cell line, compared with group C, the expression of NLRP3, caspase-1 and GSDMD was significantly up-regulated, and the concentrations of IL-18 and IL-1β were increased in group LPS/ATP ( P<0.05). Compared with group LPS/ATP, the expression of NLRP3, caspase-1 and GSDMD was significantly down-regulated, the concentrations of IL-18 and IL-lβ were decreased in group HU308 ( P<0.05). There was no significant differences in the indicators mentioned above between group V5-NC-C and group OE-C, between group LV5-NC-LPS/ATP and group OE-LPS/ATP, and between group LV5-NC-HU308 and OE-HU308 ( P>0.05). Conclusion:Over-expression of CB2R gene cannot effectively inhibit the occurrence of macrophage pyroptosis, and only activation of CB2R can inhibit it in mice.

Objective:To evaluate the relationship between the mechanism of protective effect of hydromorphone postconditioning on myocardium and phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) signaling pathway-mediated autophagy in rats.Methods:Forty healthy male Sprague-Dawley rats, weighing 220-250 g, were divided into 5 groups ( n=8 each) using a random number table method: sham operation group (Sham group), ischemia-reperfusion (I/R) group (group IR), hydromorphone postconditioning group (group HP), PI3K inhibitor group (group W) and hydromorphone postconditioning+ PI3K inhibitor group (group HP+ W). Myocardial ischemia was induced by 30 min occlusion of left anterior descending branch of coronary artery followed by 120 min reperfusion.In group HP, hydromorphone 0.1 mg/kg was injected via femoral vein at 5 min before reperfusion in group HP.In group HP+ W, hydromorphone 0.1 mg/kg and wortmannin (PI3K inhibitor) 15 μg/kg were injected via femoral vein at 5 min before reperfusion.In group W, wortmannin 15 μg/kg was injected via femoral vein at 5 min before reperfusion.At the end of reperfusion, the myocardial infarct size (IS) was determined by TTC staining, the activities of serum lactate dehydrogenase (LDH) was detected by colorimetry, myocardial specimens were collected for microscopic examination of the ultrastructure (with a electron microscope), the expression of phosphorylated Akt (p-Akt) and microtubule-associated protein 1 light chain 3 (LC3) was determined by Western blot and the ratio of LC3-Ⅱ/Ⅰwas calculated. Results:Compared with Sham group, IS and the activities of serum of LDH were significantly increased, p-Akt expression in myocardial tissues was up-regulated, the ratio of LC3-Ⅱ/Ⅰwas increased ( P<0.05), autophagic vacuoles were increased and the damage of ultrastructure of cardiomyocytes was obvious in group IR.Compared with group IR, IS and the activities of serum of LDH were significantly decreased, p-Akt expression in myocardial tissues was up-regulated, the ratio of LC3-Ⅱ/Ⅰwas decreased ( P<0.05), autophagic vacuoles were decreased and the damage of ultrastructure of cardiomyocytes was attenuated in group HR.Compared with group HR, IS and the activities of serum of LDH were significantly increased, p-Akt expression in myocardial tissues was down-regulated, the ratio of LC3-Ⅱ/Ⅰwas increased ( P<0.05), autophagic vacuoles were increased and the damage of ultrastructure of cardiomyocytes was aggravated in group HR+ W. Conclusion:The mechanism of protective effect of hydromorphone postconditioning on myocardium is related to activation of PI3K/Akt signaling pathway and inhibition of autophagy in rats.

Objective:To investigate the effect of oxycodone hydrochloride injection pretreatment on focal cerebral ischemia-reperfusion injury in rats.Methods:Seventy-two male SD rats weighing 200-250 g were randomly divided into 3 groups( n=24 each group): sham operation group (sham group), focal cerebral I/R group (I/R group), and oxycodone hydrochloride injection group (Oxy group). Focal cerebral I/R was induced by middle cerebral artery occlusion for 2 h followed by reperfusion. In the Oxy group, oxycodone hydrochloride 0.5 mg/kg was injected iv at 5 min before ischemia. While the same volume of saline (1 mL) was injected in the sham group and I/R group. The neurological deficit score (NDS) was assessed at 24 h of reperfusion, the rats were then sacrificed, and their brains were immediately removed for determination of brain water content and the infarct volume, and the histopathological changes were observed after HE staining. The levels of cytokines (TNF-α, IL-1β and IL-10) in the ischemia cortex were quantified by ELISA. MPO activity in the ischemia cortex was assessed. Western blot was used to detect the expression of NF-κB in the ischemia cortex. The data were analyzed using SPSS 20.0 software, multiple-group comparisons were performed using one-way ANOVA, and LSD- t test was used for pairwise comparison between groups. A P<0.05 was considered statistically significant different. Results:Compared with the sham group, NDS, brain water content, relative infarction volume and rate of nerve cell necrosis were significantly increased in the I/R and Oxy groups (all P<0.05). Levels of TNF-α, IL-1β, IL-10, NF-κB and the activities of MPO were increased in the ischemia cortex (all P<0.05). Compared the Oxy group with the I/R group, NDS, brain water content, relative infarction volume and rate of nerve cell necrosis were significantly decreased [(1.7±0.9) vs (2.6±1.1);(79.2±2.4)% vs (84.7±4.2)%; (23.0±5.4)% vs (34.8±6.0)%; (25.2±12.4)% vs (54.8±14.8)%, all P<0.05]. The levels of TNF-α, IL-1β, relative expression of NF-κB, and the activities of MPO were significantly decreased in the ischemia cortex [(4.4±1.2) pg/mg vs (6.5±1.2) pg/mg; (5.4±0.7) pg/mg vs (7.8±0.8) pg/mg; (0.83±0.11) vs (1.23±0.33); (0.27±0.09) U/g vs (0.36±0.14) U/g, all P<0.05] , while the concentration of IL-10 was significantly increased [(20.9±4.5) pg/mg vs (9.2±1.6) pg/mg, t=6.036, P=0.000 1]. Conclusions:Oxycodone hydrochloride can attenuate focal cerebral I/R injury through inhibiting NF-κB activity.

Objective: To evaluate the effect of irisin preconditioning on global cerebral ischemia-reperfusion (I/R) injury in rats. Methods: Thirty-six healthy male Sprague-Dawley rats, aged 8-10 weeks, weighing 250-300 g, were divided into 3 groups (n=12 each) using a random number table method: sham operation group (group S), global cerebral I/R group (group I/R) and irisin preconditioning group (group I). Global cerebral I/R was induced by occlusion of bilateral common carotid arteries combined with hypotension (MAP maintained at 35-45 mmHg) in anesthetized rats.At 30 min before ischemia, irisin 10 μg/kg (diluted to 10 μg/ml in normal saline) was intravenously injected in group I, and the equal volume of normal saline was intravenously injected in S and I/R groups.Morris water maze test was performed at day 3 of reperfusion to assess the cognitive function.Rats were sacrificed after the end of morris water maze test, and brains were removed for determination of histopathologic changes in hippocampal CA1 region (using HE staining), neuronal apoptosis in hippocampal CA1 region (Tunel staining), glial fibrillary acidic protein (GFAP) expression (by Western blot), myeloperoxidase (MPO) activity in the hippocampal tissues (by colorimetric assay), and contents of tumor necrosis factor-alpha (TNF-α) and interleukin-1beta (IL-1β) in hippocampal tissues (by enzyme-linked immunosorbent assay). The cell necrosis rate and apoptotic rate were calculated. Results: Compared with group S, the escape latency was significantly prolonged on 1-5 days in group I/R and on 1-3 days in group I, the time of staying at 1st quadrant was significantly shortened, the cell necrosis rate and apoptotic rate were increased, the expression of GFAP was up-regulated, and the activity of MPO and contents of TNF-α and IL-1β were increased in I/R and I groups (P<0.05 or 0.01). Compared with group I/R, the escape latency was significantly shortened on 1-5 days, the time of staying at 1st quadrant was prolonged, the cell necrosis rate and apoptotic rate were decreased, the expression of GFAP was down-regulated, and the MPO activity and contents of TNF-α and IL-1β were decreased in group I (P<0.05 or 0.01). Conclusion Irisin preconditioning can reduce the global cerebral I/R injury in rats, and the mechanism may be related to inhibiting activation of astrocytes in hippocampus and reducing inflammatory responses.

Objective To evaluate the relationship between the pathomechanism of neuropathic pain (NP)-inducced depression and autophagy in the cortex of the frontal lobe in rats.Methods Forty healthy male Sprague-Dawley rats in which IT catheters were successfully placed,aged 8-10 weeks,weighing 200-220 g,were divided into 4 groups (n =10 each) using a random number table method:sham operation group (group S),group NP,NP plus dimethyl sulfoxide group (group ND) and NP plus autophagy inducer rapamycin group (group NR).The neuropathic pain model was established by ligation of the left fifth spinal nerve of anesthetized rats in NP,ND and NR groups.Rapamycin 0.1 μgwas intrathecally injected via the intrathecal catheter immediately after ligation of the spinal nerve and every day after ligation once a day for 21 consecutive days in group NR.The equal volume of dimethyl sulfoxide was intrathecally injected instead of rapamycin in group ND.The mechanical paw withdrawal threshold (MWT) was measured before ligation and at 1,3,7,10,14 and 21 days after ligation.The forced swimming test was performed at 3 days before ligation and 14 and 21 days after ligation.The rats were sacrificed after the last measurement of the behaviour testing,and the prefrontal cortex was removed for determination of the expression of microtubule-associated protein light chain 3 Ⅰ (LC3 Ⅰ) and LC3 Ⅱ,Beclin-1 and p62 (by Western blot).The ratio of LC3 Ⅱ/LC3 Ⅰ was calculated.Results Compared with group S,the MWT was significantly decreased after ligation,the time of immobility was prolonged,the expression of LC3 Ⅰ was down-regulated,the expression of LC3 Ⅱ,Beclin-1 and p62 was up-regulated,and the LC3 Ⅱ/LC3 Ⅰ ratio was increased in NP and ND groups (P＜0.05).Compared with group NP,the MWT was significantly increased after ligation,the time of immobility was shortened,the expression of LC3 [and p62 was down-regulated,the expression of LC3 Ⅱ and Beclin-1 was up-regulated,and the LC3 Ⅱ/LC3 Ⅰ ratio was increased in group NR (P＜0.05).Conclusion Enhanced autophagy in the cortex of the frontal lobe is involved in the endogenous antidepressant mechanism in rats with NP.

Objective To compare the efficacy of different concentrations of pyruvate-based peritoneal dialysis solution for peritoneal resuscitation in a rat model of hemorrhagic shock.Methods Forty SPF healthy male Sprague-Dawley rats,weighing 200-250 g,were assigned to 4 groups (n=10 each) using a random number table method:sham operation group (S group),routine Ⅳ resuscitation group (VR group),and intraperitoneal resuscitation with different concentrations of pyruvate-based peritoneal dialysis solution groups (PY1 group,PY2 group).The animals were anesthetized with pentobarbital sodium 400 mg/kg.Hemorrhagic shock was induced by withdrawing blood from the left femoral artery until mean arterial pressure (MAP) was reduced to 30-40 mmHg and maintained for 60 min,and the animals were then resuscitated by infusion of shed blood.In VR group,hemorrhagic shock was resuscitated by retransfusion of autologous blood and with normal saline 2 times the volume of blood loss at 1 h after hemorrhagic shock.Routine Ⅳ resuscitation was performed,and 40 and 80 mmol/L peritoneal dialysis solution 20 ml were intraperitoneally infused for 30 min at the same time in PY1 and PY2 groups,respectively.MAP was recorded before blood-letting (T0),at 5,30 and 60 min of shock (T1-3) and 5,30,60,90 and 120 min after the end of resuscitation (T4-8).Blood samples were collected at T8 for blood gas analysis,and pH value,partial pressure of oxygen (PaO2),partial pressure of carbon dioxide (PaCO2),base excess (BE),and bicarbonate ion concentration (HCO3-) were recorded.Results Compared with S group,MAP was significantly decreased at T1-8 in VR and PY1 groups and at T1-7 in PY2 group,and pH value,PaO2,BE and HCO3-were significantly decreased,and PaCO2 was increased in VR group (P＜0.05).Compared with VR group,MAP at T4-8,pH value,PaO2,BE and HCO3-were significantly increased,and PaCO2 was decreased in PY1 and PY2 groups (P＜0.05).Compared with PY1 group,MAP at T6-8 and pH value were significantly increased (P＜0.05),and no significant change was found in PaO2,PaCO2,BE or HCO3-in PY2 group (P＞0.05).Conclusion Peritoneal resuscitation with 80 mmol/L pyruvate-based peritoneal dialysis solution produces better efficacy than 40 mmol/L in a rat model of hemorrhagic shock.

Objective To evaluate the effect of pyruvate peritoneal resuscitation on Janus kinase (JAK) /signal transducer and activator of transcription (STAT) signaling pathway in intestinal tissues of rats with hemorrhagic shock.Methods Twenty-four healthy male Sprague-Dawley rats,weighing 200-300 g,were divided into 3 groups (n=8 each) using a random number table method:sham operation group (S group),intravenous resuscitation group (VR group),and peritoneal resuscitation with pyruvate group (PY group).Hemorrhagic shock was induced by blood-letting and infusing blood withdrawn with mean arterial pressure reduced to 30-40 mmHg for 60 min in pentobarbital-anesthetized rats.Hemorrhagic shock was resuscitated with autologous blood and normal saline 2 times the volume of blood withdrawn at the end of hemorrhagic shock in group VR.Pyruvate was intraperitoneally infused for 30 min using a micro-perfusion pump simultaneously with the intravenous resuscitation in group PY.The animals were sacrificed at 2 h after resuscitation,and intestinal tissues were obtained for determination of malondialdehyde (MDA) content (by thiobarbituric acid method),superoxide dismutase (SOD) activity (using xanthine oxidase method),myeloperoxidase (MPO) activity (using chemical colorimetry),and expression of phosphorylated STAT3 (pSTAT3),phosphorylated JAK2 (p-JAK2) and caspase-3 expression (by Western blot).Results Compared with group S,the MDA content and MPO activity were significantly increased,the SOD activity was decreased,and the expression of p-STAT3,p-JAK2 and caspase-3 was up-regulated in the other two groups (P＜0.05).Compared with group VR,the MDA content and MPO activity were significantly decreased,the SOD activity was increased,and the expression of p-STAT3,p-JAK2 and caspase-3 was down-regulated in group PY (P＜0.05).Conclusion The mechanism by which peritoneal resuscitation with pyruvate mitigates intestinal damage may be related to inhibiting activation of JAK/STAT signaling pathway in the rats with hemorrhagic shock.

Objective To evaluate the effect of oxycodone on acute lung injury (ALI) induced by lipopolysaecharide (LPS) in rats. Methods Thirty-six pathogen-free healthy male Sprague-Dawley rats, weighing 250-300 g, were divided into 3 groups (n= 12 each) using a random number table: sham opera-tion group (group S), LPS-induced ALI group (group A) and oxycodone group (group O). ALI was in-duced by injecting LPS 8 mg∕kg intravenously in A and O groups, while the equal volume of normal saline was given instead in group S. Oxycodone 2 mg∕kg was injected intravenously at 10 min before LPS injection in group O, while the equal volume of normal saline was given instead in S and A groups. Rats were sacri-ficed at 6 h after LPS injection, and the broncho-alveolar lavage fluid (BALF) was collected for detection of tumor necrosis factor-alpha (TNF-α) and interleukin-1beta (IL-1β) concentrations by enzyme-linked im-munosorbent assay. Pulmonary specimens were obtained for microscopic examination of the pathological changes and for determination of wet∕dry weight ratio (W∕D ratio) and expression of Toll-like receptor 4 (TLR4) in lung tissues (using real-time polymerase chain reaction and Western blot). Results Compared with group S, the TNF-α and IL-1β concentrations in BALF, W∕D ratio, pathological scores and expres-sion of TLR4 were significantly increased at 6 h after LPS injection in A and O groups (P<0. 05). Com-pared with group A, the TNF-α and IL-1β concentrations in BALF, W∕D ratio, pathological scores and expression of TLR4 were significantly decreased at 6 h after LPS injection in group O (P<0. 05). Conclu-sion Oxycodone can attenuate LPS-induced ALI in lung tissues, and the mechanism is related to down-regulating the expression of TLR4 and inhibiting inflammatory responses of rats.