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Objective To investigate the change in expressions of lipoxin A4 (LXA4) and lipoxin A4 receptor (ALX) in rats with fat embolism syndrome(FES).Metbods Sixty healthy male SD rats were assigned to control group and FES group which was subgrouped at l,6,12 and 24 h according to the random number table,with 12 rats each.Allogeneic perinephric fat (0.706 ml/kg) was injected to rat caudal veins in FES group.Instead isotonic saline in an equal volume was given to rats in control group.Lung samples were harvested from each group to detect pathological morphology,concentration of total protein and LXA4 in bronchoalveolar lavage fluid (BALF),lung weight to dry ratio (W/D),and activity of myeloperoxidase (MPO) and ALX mRNA.Additional 40 SD rats were divided into control group,FES 24-hour group,BML-1 11 + FES 24-hour group,and Boc-2 + FES 24-hour group according to the random number table,with 10 rats each.Pathology of lung tissue was observed using microscopy and expression of lung MPO mRNA was detected.Results Lung tissues in FES group were seriously injured compared with control group.Total protein concentration in BALF was (71.12 ± 11.05) μg/ml in FES 12-hour group,significantly increased compared to (29.82 ± 0.64) μg/ml in control group (P ＜ 0.05).LXA4 concentration in BALF was (2.72 ± 0.24) ng/ml in FES 24-hour group,significantly higher than (0.69 ±0.05)ng/ml in control group (P ＜ 0.05).Lung W/D value was 9.13 ±0.83 and 9.60 ±0.86 respectively in FES 6-hour and 12-hour groups,higher than 3.09 ±0.10 in control group (P ＜0.05).Activity of MPO in lung tissue was (0.74± 0.07)U/g and (0.53 ±0.08)U/g respectively in FES 6-hour and 12-hour groups,significantly higher than (0.19 ± 0.03) U/g in control group (P ＜ 0.05).Expression of ALX mRNA was 3.99 ± 1.09 in FES 24-hour group,significantly higher than 1.00 ±0.21 in control group (P ＜0.05).Expression of MPO mRNA was lower in BML-111 + FES 24-hour group (0.69-0.08) and was higher in Boc-2 + FES 24-hour group (2.05-0.14),when compared to 1.52 ±-0.07 in FES 24-hour group (P＜0.05).Conclusion LXA4 mainly involves in the resolution of inflammation in FES rats,which may be achieved at least in part by binding to ALX.
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Objective To evaluate the effect of BML?111 on ventilator?induced lung injury in rats. Methods Forty?eight healthy male Sprague?Dawley rats, weighing 200-250 g, aged 6-8 weeks, were randomized into 6 groups ( n=8 each) using a random number table: control group ( C group) , low tidal volume (VT) group (LVTgroup), high VT group (HVTgroup), low dose BML?111 group (BL group), high dose BML?111 group ( BH group) , and BML?111 plus BOC?2 ( lipoxin A4 receptor antagonist) group ( BOC?2 group) . Group C kept spontaneous breathing after tracheotomy, and received no mechanical venti?lation. The rats in the other 5 groups were mechanically ventilated ( respiratory rate 80 breaths∕min, frac? tion of inspired oxygen 21%, positive end?expiratory pressure 0) . The VT was 6 ml∕kg in group LVT , or 20 ml∕kg in HVT, BL, BH and BOC?2 groups. BML?111 0?1 and 1?0 mg∕kg were injected intraperitoneally during ventilation in BL and BH groups, respectively. In group BOC?2, BOC?2 50 μg∕kg was injected in?traperitoneally before ventilation, and BML?111 1?0 mg∕kg was injected intraperitoneally during ventilation. Arterial blood samples were collected at 4 h of ventilation, arterial oxygen partial pressure ( PaO2 ) was de?termined. Then animals were sacrificed by exsanguination. Bronchoalveolar lavage fluid ( BALF) of the left lung was collected for determination of neutrophil count, and the level of neutrophil was calculated. The right lung tissue specimens were obtained for microscopic examination, and for determination of wet∕dry lung weight ratio ( W∕D ratio ) , myeloperoxidase ( MPO ) activity, and contents of malondialdehyde ( MDA) , monocyte chemoattractant protein?1 ( MCP?1) , tumor necrosis factor?alpha ( TNF?α) , interleu?kin?1beta ( IL?1β) and IL?6. Results Compared with group C, PaO2 was significantly decreased, and the level of neutrophil in BALF, W∕D ratio, MPO activity, and contents of MDA, MCP?1, TNF?α, IL?1β and IL?6 were increased in group HVT ( P0?05) . Compared with group HVT , PaO2 was significantly increased, and the level of neutrophil in BALF, W∕D ratio, MPO activity, and contents of MDA, MCP?1, TNF?α, IL?1β and IL?6 were decreased in group BH, and the contents of TNF?α, IL?1βand IL?6 were significantly decreased ( P0?05) . Compared with group BH, PaO2 was significantly decreased, and the level of neutrophil in BALF, W∕D ratio, MPO activity, and contents of MDA, MCP?1, TNF?α, IL?1β and IL?6 were increased in group BOC?2 (P<0?05). The pathological changes were significantly attenuated in group BL as compared with HVT and BOC?2 groups. Conclusion BML?111 can attenuate ventilator?induced lung injury in rats, and activated lipoxin A4 receptors are involved in the mechanism.
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Objective To evaluate the effect of BML-111 on NF-κB pathway during acute lung injury induced by hemorrhagic shock and resuscitation in rats.Methods Thirty-two adult male Sprague-Dawley rats,weighing 200-250 g,were randomly divided into 4 groups (n =8 each) using a random number table:sham operation group (group S),hemorrhagic shock and resuscitation group (group HSR),BML-111 group,and BML-111 + BOC-2 (lipoxin A4 receptor antagonist) group (group BOC-2).The animals were anesthetized with intraperitoneal pentobarbital sodium.Hemorrhagic shock was induced by blood letting and maintained for 30 min.The animals were then resuscitated for 30 min by infusion of the shed blood and lactated Ringer's solution.In group BOC-2,BOC-2 (50 μg/kg) was injected intraperitoneally before blood letting.In BML-111 and BOC-2 groups,BML-111 (1 mg/kg) was injected intraperitoneally at the beginning of resuscitation.The rats were sacrificed at 2 h after the end of resuscitation and lungs were removed for determination of pathological changes,myeloperoxidase (MPO) activity,intercellular adhesion molecule-1 (ICAM-1) expression (by immunohistochemistry),tumor necrosis factor-alpha (TNF-α) content (by ELISA),and NF-κB p65 and IκB-α expression (by Western blot).Results Compared with group S,the MPO activity,ICAM-1 expression,and TNF-α content were significantly increased,NF-κB p65 expression was up-regulated,and IκB-α expression was down-regulated in group HSR.Compared with group.HSR,the MPO activity,ICAM-1 expression,and TNF-α content were significantly decreased,NF-κB p65 expression was down-regulated,IκB-α expression was up-regulated,and pathological changes of lung were attenuated in group BML-111.Compared with group BML-111,the MPO activity,ICAM-1 expression,and TNF-α content were significantly increased,NF-κB p65 expression was up-regulated,and lκ:B-α expression was down-regulated,and pathological changes of lung were aggravated in group BOC-2.Conclusion BML-1 11 inhibits activation of NF-κB pathway and inflammatory responses,thus mitigating acute lung injury induced by hemorrhagic shock and resuscitation in rats.
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Objective To evaluate the effect of lipoxin A4 receptor agonist BML-111 on acute lung injury induced by hemorrhagic shock and resuscitation in rats.Methods Thirty-two healthy male Sprague-Dawley rats,aged 6-8 weeks,weighing 200-250 g,were randomized into 4 groups (n =8 each) using a random number table:sham operation group (S group),hemorrhagic shock/resuscitation group (HSR group),BML-111 group,and BML-111 plus BOC-2 (lipoxin A4 receptor antagonist) group (BOC-2 group).The animals were anesthetized with 2％ pentobarbital sodium 80 mg/kg,tracheostomized and mechanically ventilated.Left common carotid artery was cannulated for blood-letting and fluid infusion.Hemorrhagic shock was induced according to the method described by Kochanek et al.MAP was reduced to 35-45 mmHg and maintained at this level for 30 min.The animals were then resuscitated for 30 min with infusion of the blood withdrawn and lactated Ringer' s solution 2 times the volume of blood withdrawn.In BML-111 and BOC-2 groups,BML-111 (1 mg/kg) was injected intraperitoneally at the beginning of resuscitation.In BOC-2 group,BOC-2 (50 μg/kg) was injected intraperitoneally before blood-letting.The rats were sacrificed at 2 h after completion of resuscitation.Bronchoalveolar lavage fluid (BALF) was collected for determination of neutrophil count.Lungs were excised for microscopic examination of the pathological changes and for determination of wet/dry lung weight ratio (W/D ratio),contents of interleukin-1 (IL-1β) and IL-6,and phosphorylation of mitogen-activated protein kinase (MAPK).Results Compared with group S,the neutrophil count in BALF,W/D ratio,contents of IL-1β and IL-6,and phosphorylation of MAPK were significantly increased in HSR group (P ＜ 0.05).The neutrophil count in BALF,W/D ratio,contents of IL-1β and IL-6,and phosphorylation of MAPK were significantly lower in BML-111 group than in HSR group,and higher in BOC-2 group than in BML-111 group (P ＜ 0.05).Conclusion BML-111 can attenuate acute lung injury induced by hemorrhagic shock and resuscitation in rats and inhibition of activation of MAPK pathways and reduction of inflammatory responses in lung tissues are involved in the mechanism.