| Objective:To investigate the protective effects of adiponectin (APN) pretreatment on mitochondrial oxidative stress in acute lung injury induced by sepsis.Methods:The model of sepsis was set up by CLP in120Wistar male rats (weighting180-220g, at the age of7-8weeks old), sixty of which were chosen and randomly divided into3groups (twenty rats in each group):control group (C group), CLP group and APN pretreatment group (APN/CLP group). Animals in APN/CLP group received APN6mg/kg before underwent CLP. The general situation of rats in each group was observed, including general condition, breathing rate, heart rate, body temperature, reaction and diet. And a comparison of the survival for7days among all groups was done. The other sixty rats were used to do the following procedures, using the previous grouping method.6and24hours after CLP, ten rats in each group were sacrificed to collect lung tissue samples. The histopathological changes of lung tissues were evaluated, and the lung injury scores were recorded. The levels of interlukin-6(IL-6) and high mobility group box1(HMGB1) in lung tissue samples were examined. Furthermore, pulmonary mitochondria isolation was performed. Mitochondrial membrane swelling degree and the mitochondrial membrane potential were recorded. Mitochondrial manganese superoxide dismutase (Mn-SOD) activity, malondialdehyde (MDA) and glutathione (GSH) levels were measured. And the correlation analysis was done between IL-6, HMGB1in lung and Mn-SOD, GSH and MDA in lung mitochondria in CLP group, respectively. Results:1. Compared with C group, there is a significant performance of sepsis in CLP and APN/CLP groups. The survival rate7days after CLP were significantly decreased (P<0.05), the lung injury scores, levels of IL-6and HMGB124h after CLP were markedly increased (P<0.05), and the mitochondrial swelling degree was significantly increased (P<0.05), mitochondrial membrane potential and Mn-SOD activity were decreased significantly (P<0.05), mitochondrial MDA levels were increased (P<0.05), and GSH levels of lung mitochondria were decreased (P<0.05) at6and24h after procedures in CLP and APN/CLP groups.2. Compared with CLP group, the performance of sepsis was improved in APN/CLP group. The survival rate7days after CLP were increased significantly (P<0.05), the lung injury scores, levels of IL-6and HMGB124h after CLP were markedly decreased (P<0.05), and the mitochondrial swelling degree was decreased (P<0.05), mitochondrial membrane potential and Mn-SOD activity were elevated significantly (P<0.05), mitochondrial MDA levels were reduced significantly (P<0.05), and GSH levels of lung mitochondria were increased (P<0.05) at6and24h after procedures in APN/CLP group.3. Compared with indicators at6h after CLP, the mitochondrial swelling degree was increased (P<0.05), mitochondrial membrane potential decreased (P<0.05), and mitochondrial Mn-SOD activity as well as GSH levels were elevated (P<0.05) at24h in CLP and APN/CLP groups, respectively. While there was no significant difference in mitochondrial MDA levels between6h and24h after CLP in CLP and APN/CLP groups (P>0.05).4. There was a positive correlation between lung IL-6, HMGB1and mitochondrial MDA (r=0.744, P=0.014; r=0.785, P=0.007), a negative correlation between IL-6, HMGB1and mitochondrial Mn-SOD activity (r=-0.781, P=0.008; r=-0.832, P=0.003), and a negative correlation between lung IL-6, HMGB1and lung mitochondrial GSH (r=-0.754,P=0.012; r=-0.907, P=0.000) in CLP group.Conclusion:APN might play a protective role on acute lung injury in CLP-induced septic rats through depressing the inflammatory response and reducing oxidative stress so as to alleviate mitochondrial damage and improve mitochondrial function in lung tissues. Objective:To investigate the protective effects of adiponectin (APN) on mitochondrial biogenesis in cecal ligation and puncture (CLP)-induced septic rats.Methods:The model of sepsis was set up by CLP in60Wistar male rats (weighting180-220g, at the age of7-8weeks old), which were randomly divided into3groups: control group (C group), CLP group and APN pretreatment group (APN/CLP group). Animals in APN/CLP group received APN6mg/kg before underwent CLP. At6and24hours after CLP,10rats in each group were chosen. The animals were sacrificed to collect lung tissue samples in all groups. The lung histopathological change was observed and the lung injury score was recorded. The lung mitochondrial DNA copy number was detected. The mRNA levels of the mitochondrial transcription factor of biogenesis, including peroxisome proliferators activated receptor y coactivator-1α (PGC-la), nuclear respiratory factor1(NRF-1), nuclear respiratory factor2(NRF-2) and mitochondrial transcription factor A (Tfam), the mRNA levels of mitochondrial DNA repair enzyme8-oxoguannine DNA glycosidase (OGG1) as well as the protein expression of PGC-1α in lung tissues were measured.Results:1. Compared with C group, the lung injury score was increased significantly (P <0.05), the lung mitochondrial DNA copy number was decreased significantly (P<0.05), the mRNA levels of PGC-la, NRF-1and NRF-2as well as OGG1in lung tissues were increased (P<0.05) in CLP group6h after CLP. There were no significant differences in Tfam mRNA or PGC-1α expressions (P>0.05). Compared with CLP group, the lung injury score was down (P<0.05), the lung mitochondrial DNA copy number was increased significantly (P<0.05), the mRNA levels of PGC-1α, NRF-1and NRF-2as well as OGG1in lung tissues were increased (P<0.05) in APN/CLP group6h after CLP. And there were no significant differences in Tfam mRNA or PGC-1α expressions (P>0.05).2. Compared with C group, the lung injury score was increased markedly (P<0.05), the lung mitochondrial DNA copy number was decreased significantly (P<0.05), the mRNA levels of PGC-1α, NRF-1, NRF-2and Tfam as well as OGG1in lung tissues were increased (P<0.05) in CLP group24h after CLP. Compared with CLP group, the lung injury score was decreased (P<0.05), the lung mitochondrial DNA copy number was increased significantly (P<0.05), the mRNA levels of PGC-1α, NRF-1, NRF-2and Tfam as well as OGG1in lung tissues were increased (P <0.05) in APN/CLP group24h after CLP.3. Levels of the above indicators except for Tfam mRNA detected in CLP group24h after CLP were lower than those which were measured6h after CLP (P<0.05).Conclusion:APN might play a protective role on lung injury in CLP-induced septic rats through up-regulating mRNA levels of the mitochondrial transcription factor of biogenesis, including PGC-1α, NRF-1, NRF-2and Tfam as well as the mRNA level of mitochondrial DNA repair enzyme OGG1, increasing mtDNA copy numbers and repairment in lung tissues.
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