Objective To investigate the effect of cyclic tensile stress (CTS) on the metabolism inand apoptosis of rat chondrocytes.Methods Primary rat chondrocytes were cultured on a Bioflex plate for one day and then stretched cyclically for 24 hours at a frequency of 0.5 Hz using a Flexcell-5000T apparatus.The cells were divided into 5 groups according to their stretching ratio:0％ (the control group),2％,6％,10％ and 14％.After the stretching,Col Ⅱ,Aggrecan,MMP-13 and ADAMTS-5 mRNA were measured using qPCRs,and the NO and PGE2 levels were measured using ELISA kits.Moreover,TUNEL staining and Annexin V-FITC/PI were used to analyze the apoptosis of chondrocytes.Results Compared with the control group,the average levels of Col Ⅱ and Aggrecan mRNAdecreasedin 10％ and 14％ groups [(0.738±0.11) and (0.58±0.13),(0.75±0.11) and (0.55±0.09)].In those groups,the MMP-13 [(2.47±0.47) and (2.88±0.36)] and ADAMTS-5 mRNA level [(2.39±0.33) and (2.75±0.49)],the NO [(6.96±0.96) and (8.28±0.82)] and PGE2 level [(6.83±0.66) and (7.15±0.71)] had increased significantly.In the 6％ group the average levels of Col Ⅱ(1.76±0.30) and Aggrecan mRNA (1.93±0.14)of 6％ group were significantly higher than the control group,but the NO level of the former (3.07±0.20) was significantly lower than the control group (3.89 ± 0.33).The apoptosis rate of chondrocytesin 2％ and 6％ groups were (0.065±0.013) and (0.063 ± 0.147),without significant differences to that of the control group (0.045 ± 0.008).However,compared with the control group,apoptosis in the 10％ and 14％ groups [(0.135 ±0.026) and (0.184±0.020)] increased significantly.Conclusion The effect of cyclic tensile stress on chondrocyte metabolism and apoptosis was magnitude-dependent.Ten percent and 14％ CTS can increase the catabolism and apoptosis of chondrocytes.Ten percent and 14％ strain can increase the catabolism and apoptosis of chondrocytes.Cyclic 6％ strain can increase the anabolism of chondrocytes,but 2％ strain has no impact on metabolism or apoptosis.

Objective To explore the role of resolvin D1 in reducing brain injury after porcine cardiopulmonary resuscitation and its potential mechanisms.Methods Twenty-eight male domestic pigs weighing (36 ±3)kg were utilized.The animals were randomly divided into 4 groups (n =7 each):sham operation group (group S),cardiopulmonary resuscitation group (group CPR),low-dose resolvin D1 gToup (group LRD),and high-dose resolvin D1 group (group HRD).The animals in group S only got the general preparation without the procedure of cardiac arrest and resuscitation.The pig model was established by 8 mins of untreated ventricular fibrillation and then 5 mins of cardiopulmonary resuscitation.At 5 min post-resuscitation,the doses of resolvin D10.3 μg/kg,and 0.6 μg/kg were correspondingly injected via the femoral vein in LRD and HRD groups,and meanwhile the same amount of vehicle was given into the animals inthe other two groups.At 3 h,6 h and 24 h post-resuscitation,the concentrations of neuron specific enolase (NSE) and S100B protein (S100B) in serum was measured.At 24 h post-resuscitation,neurological deficit score (NDS) was evaluated;thereafter the pigs were sacrificed,and cerebral cortex was obtained for the determination of tumor necrosis factor-alpha (TNF-α),interleukin-6 (IL-6),and malondialdehyde (MDA) contents,and superoxide dismutase (SOD) activity.Results Compared to group S,post-resuscitation brain injury was observed in the other three groups,which was indicated by significantly increased NDS score,and markedly elevated concentrations of serum NSE and S100B.Compared to group CPR,the NDS was significantly decreased at 24 h post-resuscitation,and the concentrations of serum NSE and S100B were significantly reduced at 6 h and 24 h post-resuscitation in LRD and HRD groups.Compared to group LRD,the NDS score and its serum markers were further significantly decreased in group HRD.The inflammatory response and oxidative stress in brain tissue were observed in all the animals experiencing cardiac arrest and resuscitation,which were indicated by increased contents of TNF-α,IL-6 and MDA and decreased SOD activity.Compared to group CPR,the contents of TNF-α,IL-6 and MDA were significantly decreasedwhile SOD activity was significantly increased in LRD and HRD groups.The indicators of inflammatory response and oxidative stress in brain tissue were further significantly improved in group HRD when compared to group LRD.Conclusions Resolvin D1 can reduce post-resuscitation brain injury in a dose-dependent manner in swine,and the mechanism is related to the inhibition of inflammatory response and oxidative stress.

To explore the mechanisms by which AKR1C3 induces tumor resistance, human breast cancer cell strain MCF-7/DOX resistant to doxorubicin, MCF-7/ AKR1C3 cells for overexpression of AKR1C3 and MCF-7/DOX-KD cells for knockdown of AKR1C3 in MCF-7/DOX cells were established. Western blot analysis found that AKR1C3 was expressed at a higher level in MCF-7/DOX than MCF-7 wild type cells. Similarly, CCK-8 and DAPI confirmed that MCF-7/ AKR1C3 cells were more resistant to DOX than AKR1C3 wild types as the IC50 was increased 6 times in MCF-7/AKR1C3 cells more than in AKR1C3 wild type cells. Meanwhile, colony formation ability was also enhanced after AKR1C3 was over-expressed in MCF-7 cells.Cytoplasmic/nuclear separation analysis and IF further found that β-catenin nuclear translocation mediated by AKR1C3 was the main reason contributing to the occurrence of DOX-resistant breast cancer cells. β-catenin inhibitor, XAV939, could reverse the AKR1C3 induced doxorubicin resistance in MCF-7 cells.Results indicated that AKR1C3 could be a potential therapeutic target in breast cancer cells.

Objective To establish a porcine model of cardiopulmonary resuscitation to explore the effectiveness of resolvin D1 in improving post-resuscitation myocardial dysfunction and its potential mechanisms.Methods Twenty-eight male domestic pigs weighing 36 ± 3 kg were utilized.The pig model was established by 8 mins of untreated ventricular fibrillation and then 5 mins of cardiopulmonary resuscitation.The animals were randomly divided into 4 groups (n =7 each):sham operation group (group S),cardiopulmonary resuscitation group (group CPR),low-dose resolvin D1 group (group LRD),and high-dose resolvin D1 group (group HRD).The animals in group S only got the general preparation without the procedure of cardiac arrest and resuscitation.At 5 min after resuscitation,the doses of resolvin D1 0.3 μg/kg and 0.6 μg/kg were respectively injected via the femoral vein of pigs in LRD and HRD groups,and meanwhile the equal volume of vehicle was given into the animals in the other two groups.At 3 h,6 h and 24 h after resuscitation,the changes of stroke volume (SV) and global ejection fraction (GEF) were evaluated by a PiCCO monitor,and meanwhile the concentration of cardiac troponin I (cTNI) in serum was measured.At 24 h after resuscitation,the pigs were sacrificed,and myocardial tissue was obtained for the determination of tumor necrosis factor-alpha (TNF-α),interleukin-6 (IL-6),malondialdehyde (MDA),and superoxide dismutase (SOD) activity.Results Compared with group S,significantly decreased SV and GEF and markedly increased concentration of serum cTNI were observed in the other three groups with post-resuscitation myocardial dysfunction (all P ＜ 0.05).Compared with group CPR,the values of SV and GEF were significantly increased while the concentration of serum cTNI was significantly decreased in LRD and HRD groups [SV (ml):28 ±5,31 ±5 vs.23 ±4 at 3 hrs,32 ±3,36 ±6 vs.27 ± 6 at6 hrs,35 ±5,41 ±5 vs.29±5 at24 hrs;GEF (％):17±2,19±2 vs.14±1 at3 hrs,20±2,23 ± ±3 vs.16 ±3 at 6 hrs,23 ±2,26 ±3 vs.20 ±2 at 24 hrs;cTNI (pg/ml):247 ±34,230 ±26 vs.324 ± 56 at 3 hrs,553 ± 37,501 ± 34 vs.611 ± 44 at 6 hrs,436 ± 23,371 ± 29 vs.553 ± 47 at 24 hrs,all P ＜ 0.05].Compared with group LRD,myocardial function and serum markers were further significantly improved in group HRD (all P ＜ 0.05).The inflammation and oxidative stress in myocardial tissue were observed in all the animals experiencing cardiac arrest and resuscitation,which were indicated by increased levels of TNF-α,IL-6 and MDA and decreased SOD activity.Compared with group CPR,the levels of TNF-α,IL-6 and MDA were significantly decreased while SOD activity was significantly increased in LRD and HRD groups [TNF-α (pg/ml):442 ±87,218 ±55 vs.653 ± 112;IL-6 (pg/ml):563 ± 68,403±61vs.824±117;MDA (nmol/mg):3.95±0.96,2.54±1.21vs.6.37±1.26;SOD (U/mg):2.27±0.93,3.36±0.74vs.0.89±0.31,all P＜0.05].The morbidity of myocardial inflammation and oxidative stress were further significantly ameliorated in group HRD evidenced by the figure of biomarkers compared with group LRD (all P ＜ 0.05).Conclusions Resolvin D1 can improve post-resuscitation myocardial dysfunction in a dose-dependent manner in swine,and the mechanism is related to the inhibition of inflammation and oxidative stress.

Objective To investigate the effects of dexmedetomidine postconditioning on brain injury after cardiac arrest and resuscitation in a swine model.Methods Twenty-eight healthy male domestic pigs,weighing 36±2 kg,were randomized (random number) into 4 groups (n=7 each group):sham operation group (S group),cardiopulmonary resuscitation group (CPR group),low-dose dexmedetomidine postconditioning group (LDP group),and high-dose dexmedetomidine postconditioning group (HDP group).Animals in the S group only underwent the surgical preparation.In the other three groups,the experimental model was established by 8 mins of electrically induced ventricular fibrillation and then 5 mins of cardiopulmonary resuscitation.At 5 min after resuscitation,a loading dose of dexmedetomidine of 0.25 μg/kg was intravenously infused followed by continuous infusion at a rate of 0.25 μg/(kg·h) for 6 h in the LDP group,and a loading dose of dexmedetomidine of 0.5 μ.g/kg was infused followed by continuous infusion at a rate of 0.5 μg/(kg·h) for 6 h in the HDP group.The same amount of normal saline was administered in the S and CPR groups.At 1 h,3 h,6 h and 24 h after resuscitation,the levels of serum neuron specific enolase (NSE) and S100B protein were measured.At 24 h after resuscitation,neurologic deficit score (NSD) was evaluated.After that,the animals were euthanized and cerebral cortex was obtained for the determination of tumor necrosis factor-α (TNF-α),interleukin-6 (IL-6)and malondialdehyde (MDA) contents,superoxide dismutase (SOD) activity,cell apoptosis and caspase-3 expression.Results Compared with the S group,post-resuscitation neurologic dysfunction and brain injury were observed in the other three groups,which were indicated by significantly higher NDS and markedly greater levels of serum NSE and S 100B (all P＜0.05).Compared with the CPR group,the score of NDS at 24 h post-resuscitation were significantly lower and the levels of serum NSE and S100B at 6 h and 24 h post-resuscitation were significantly less in the LDP and HDP groups [NDS:194±26,103±16 vs 278±23 at 24 h;NSE (ng/mL):32.4±1.8,28.6±3.7 vs 36.2±2.8 at 6 h,39.9±4.2,35.1±1.5 vs 45.1±3.0 at 24 h;S100B (pg/mL):2 534±207,2 382±170 vs 2 825±113 at 6 h,3 719±164,3 246±176 vs 4 085±161 at 24 h,all P＜0.05].Compared with the LDP group,neurologic dysfunction and brain injury at 24 h postresuscitation were further significantly alleviated in the HDP group (all P＜0.05).Pathological analysis indicated that brain inflammation,oxidative stress and cell apoptosis were observed after resuscitation in the CPR,LDP and HDP groups.However,the contents of TNF-α,IL-6 and MDA were significantly lower while the activity of SOD was significantly higher,and cell apoptosis and caspase-3 expression were significantly reduced in the brain after resuscitation in the LDP and HDP groups compared with the CPR group (all P＜0.05).In addition,those pathological injuries mentioned above were further significantly alleviated in the brain after resuscitation in the HDP group compared to the LDP group (all P＜0.05).Conclusions Dexmedetomidine postconditioning significantly alleviated the severity of postresuscitation brain injury in a dose-dependent manner,in which the protection was produced possibly through reducing tissue inflammation,oxidative stress and cell apoptosis.