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Objective To investigate the intervention of chemokine receptor 4(CXCR4) antagonist AMD3100 in lung tissues of rats during pulmonary oxygen intoxication.Methods Forty SD rats were randomly divided into 4 groups:normal pressure air PBS group, normal pressure air antagonist group , oxygen exposure PBS group and oxygen exposure antagonist group, each consisting of 10 animals.The last two groups were compressed to 0.23 MPa at an exponential rate of 0.1 MPa/min by pure oxygen.Pathological changes of lung tissues were observed by hematoxylin eosin stain.Changes in TNF-αand IL-1βexpression levels in the lung tissues of rats were detected by ELISA.Changes in CXCR4 expression levels were ob-served by Western blotting.Results Pathological examination indicated that edema and hemorrhage in the alveolar and pulmonary interstitial tissue of oxygen exposure antagonist group were lighter than in oxygen exposure PBS group.The levels of TNF-α, IL-1βand cleaved-caspase-3 in the lung tissues of the oxygen exposure antagonist group were lower than in oxy-gen exposure PBS group.Conclusion Blocking CXCR4 with AMD3100 can effectively alleviate lung injury during pulmo-nary oxygen intoxication.
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Objective To investigate the effect of N-acetylcysteine ( NAC) on lung and heart injury of rats with a fast floating escape induced decompression sickness .Methods Eighty male Sprague-Dawley rats were randomly and evenly divided into four groups:control group and three NAC prevention groups .The NAC groups were treated with different doses of NAC(250, 500 or 1000 mg/kg)by intraperitoneal injection 1 h before entrance.In the control group, rats were given an equal volume of saline1h before entrance.The air was pressurized at the 2t/7 exponential rate to 1.5 MPa which was maintained for 4 min and then uniformly decompressed to atmospheric pressure .The extravehicular survival and pathological changes in the lung and heart tissue were detected 0.5 h after rat egress.Results The survival rate of rats treated with NAC 500 mg/kg(90%) was significantly higher than that of those treated with saline (65%)alone (P<0.05).There was large break and fusion in the structure of pulmonary alveolus of control group besides obvious erythrocyte exudation , cardiac muscle fibers edema ,and obvious denaturation and break .Conclusion NAC can play a protective role in rats with a fast floating escape induced decompression sickness by mitigating the injury to and inflammation of lung and heart tissue .
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Objective To study the pathological changes of lung tissues during fast floating escape-induced decompres-sion sickness.Methods Eighty male SD rats were randomly divided into 2 groups, 60 in fast floating escape group (escape group) , and 20 in control group .Rats in the control group were only put in a cabin under the same atmospheric pressure (ATM).Rats in escape group were pressurized to 1.5 MPa by pressure air at the 2t/7 exponential rate and stayed for 4 min till decompression.Then the rats′survival rate was observed after 0.5 h, lung tissue specimens were collected from each rat, the pathological score was taken , according to the degree of lung injury and the R language was used for statistical analysis.Results The mortality rate was 50%.Lung tissues of these rats were pathologically characterized by stromal lung thickening, edema, and hyperemia.Kruskal non-parametric test analysis found a significant difference (P=0.0016) between the two groups .Nemenyi test was used in pairwise comparison .The death and survival animals in escape group compared with the control group, the scores were significantly different (P<0.05).The scores had no significant difference between the deach and survival animal in escape group .Conclusion Decompression sickness caused by fast floating es-cape can significantly damage the blood-lung barrier to cause pulmonary edema .
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Objective Platelet aggregation, activation induced by bubbles is the main cause of decompression sick-ness.Clopidogrel(Clo) can decrease platelet aggregation through inhibiting the bind of fibrinogen and ADP .This study is designed to find if Clopidogrel can paly a protective role in decompression sickness and explore the intervention mechanism . Methods Totally 111 male SD rats divided into 3 groups:normal control group (n=20), decompression sickness(DCS) group(n=46), and DCS+Clo(Clopidogrel)treated decompression sickness (DCS+Clo)group(n=45).The rats in DCS and DCS+Clo group were placed in chamber and compressed to 1.5 MPa at speed of 2t/4 , the time of compression and res-idence was 4.5 min totally, then decompressed to surface at a speed of 3 m/s.The mortality and behavioral of rats were ob-served within 30 min post decompression .The pathology and the wet/dry ratio of lung , WBC and platelet counts in periph-eral blood, the expression of activated platelets , and immunohistochemical detection of lung tissue CD 41 expression were also been tested .Results We found Clo reduces the DCS mortality risk ( mortality rate:11/45 in DCS+Clo group vs 28/46 in DCS group, P<0.01).Clo reduced the lung injury, the wet/dry ratio of lung, the accumulation of platelet and leu-kocyte in lung , the WBC counts and activated platelets in peripheral blood .Conclusion Clo can play a protective role in decompression sickness through reducing post-decompression platelet consumption and activation , decreasing the activation of leukocytes .
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Objective To study the expression levels of microRNA (miR)-16 and miR-146a in rat lungs of decompres-sion sickness (DCS) caused by fast buoyancy ascent escape or diving .Methods At 0.5 h after fast buoyancy ascent es-cape or diving, the pathological changes in rat lungs and expression levels of miR-16,and miR-146a were detected by re-verse transcription-quantitive polymerase chain reaction and compared with normal control group .Results The pathological characteristics of lungs in two DCS groups were tissue damage .At 0.5 h after DCS caused by fast buoyancy ascent escape , the lung tissue expression levels of miR-16 and miR-146a did not significantly change compared with normal control and diving DCS groups ,but the rat lung tissue expression level of miR-146 a in diving DCS group was obviously increased , com-pared with normal control group .Conclusion miR-146a may play a role in post-transcriptional regulation in the process of diving DCS .
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Objective To investigate the effect of PPAR-δ on the lung injury of rats induced by hyperbaric oxygen (HBO2) exposure.Methods Sixty male Sprague-Dawley rats were randomly divided into six groups:air+vehicle, air+GW0742, and air+GSK0660, HBO2 +vehicle, HBO2 +GW0742, HBO2 +GSK0660.Lung injury was induced in rats by HBO2exposure (2.3 ATA, 100%O2, 8 h).Rats were injected with vehicle[10%DMSO in 0.3 ml NaCl 0.9%(v/v)] or GW0742 (0.3 mg/kg, ip) or GSK0660 (1 mg/kg, ip) at 1, 6 and 12 hours before either air or oxygen exposure .Protein levels in the bronchoalveolar lavage fluid ( BALF) , wet/dry ratio of the lung and the pathological changes in the lung tissue were detected 30 min after rats′egress.Results and Conclusion For the HBO2 +GW0742 group, the protein levels in BALF, the wet/dry ratio of the lung and the pathological changes in lung tissues all significantly decreased compared with those of the air group .These changes in HBO 2 +GSK0660 group tended to increase the level of lung injury .PPAR-δhas a protective effect on pulmonary oxygen toxicity induced by HBO 2 .
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Objective To study the effect of nicardipine on fast floating escape induced lung injury in animal models with decompression sickness .Methods Sixty male SD rats were randomly and evenly divided into three groups:blank control, control and nicardipine groups .The nicardipine group was given nicardipine 50 mg/kg orally 0.5 h before entrance.In the control group, rats were given an equal volume of saline 0.5 h before entrance.The blank control group only stayed in the vehicle without any pressurized procedure .The air was pressurized at the 2t/7 exponential rate to 1.5 Mpa which was maintained for 4 min, and then uniformly decompressed to atmospheric pressure .The extravehicular survival and lung pathology were observed in rats after 0.5 h, IL1-βand TNF-αexpression levels were detected by ELISA , and the Caspase 3 expression in lung tissue was detected by Western blot .Results The incidence and mortality rate were 80%and 50%respectively in control group ,and 100%and 80%in the experimental group .The surviving animals in the two groups suffered from alveolar and interstitial lung hemorrhage , with widened interstitial lung .IL1-βin the experimental group was significantly higher than in the normal control group , while TNF-αhad no significant change .After nicardipine treatment pro-caspase 3 did not change significantly , but cleaved-caspase 3 increased significantly .Conclusion Nicardipine can aggravate lung injury caused by fast floating escape-induced decompression sickness if used before decompression.
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To study the effect of hyperbaric oxygen (HBO) on cellular proliferative nuclear antigen (PCNA) in spinal cord after its injury (SCI), we observed the pathological changes and the expression change in PCNA in spinal cord after the injured rats were treated with HBO. The results showed that there were hemorrhage, edema, vacuolation of nerve cells in spinal cord, disorder and fragmentation in nerve fibers after injury. PCNA was strongly positively expressed in neurons. The results in 0.1MPa HBO group were similar to that of non-treatment group, while in 0.25MPa HBO group, edema was abolished, the cellular vacuolation was lessened, the morphology of nerve cells recovered, the structural configuration appeared normal, and the degree of PCNA expression was decreased compared with the injury group. These results suggested that PCNA could serve as a cellular proliferative index; HBO could prevent or alleviate the pathological changes of SCI, and could effectively promote the repair of the injury of the spinal cord.
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27 rabbits were divided into normal group(n = 4),control group (n = 5), silybin group (n = 6), hyperbaric oxygen (HBO) group (n = 6), and HBO combined with silybin group (n = 6). Circulation of hindlimb was interrupted completely for 6 h and reperfused for 1 h. Malondialdehyde (MDA) and superoxide dismutase(SOD) in plasma from ischemic-reperfused injured limb were measured. Adenosine triphosphate (ATP) and creatine phosphate (CP) in samples taken from anterior tibial muscle were determined. Ultrastructural changes of injured muscle were observed. The results showed that HBO combined with silybin treatment had a favourable effect on ischemic and reperfused injured limb muscle with reduction of the lipid peroxidated injury, increase of the SOD activity and the high energy phosphate compounds (ATP and CP), and a promoting recovery of injured muscle cells. HBO and silybin had a synergistic action. It suggests that HBO combined with silybin is an effective method for treatment of ischemic and reperfused injured limb.