Objective To investigate the effect of dexmedetomidine (DEX) on the reduction of brain injury induced by lung ischemia/reperfusion (I/R) in mices through inhibiting excessive endoplasmic reticulum stress response (ERS).Methods Fifty healthy SPF male C57BL/6J mices,weighing 20-24 g,aged 8-10 weeks,were divided into 5 groups (n =10 each) using a random number table:sham operation group (sham group),lung ischemia/reperfusion group (I/R group),atipamezole goup (Atip group),dexmedetomidine group (DEX group),dexmedetomidine plus atipamezole group (DA group).The model of lung I/R injury was established by clamping the left hilum of lung for 30 min followed by reperfusion for 180 min.In Atip,DEX and DA groups,atipamezole 250 μg/kg,dexmedetomidine 20 μg/kg and dexmedetomidine 20 μg/kg plus atipamezole 250 μg/kg were injected intraperitoneally,respectively,at 30 min before modeling,other procedures were as the same as the I/R group.At 180 min of reperfusion,the animals were sacrificed and the brain tissues were harvested for the observation of morphological changes.The Caspase-3 activity and the apoptosis index of the brain cells were also determined.The levels of protein and mRNA expression of p-JNK,Caspase-12,CHOP and GRP78 in brain tissues were detected by Western blot and RT-PCR.The datas were analyzed using SPSS 19.0 software and multiple-group comparisons were performed using one-way ANOVA,and P ＜ 0.05 for the difference was statistically significant.Results Compared with the sham group,the Caspase3 activity and brain cell apoptosis index,the protein levels and mRNA expressions of p-JNK,Caspase12,CHOP,GRP78 were significantly increased (P ＜ 0.01),brain tissues had obvious damage in I/R,Atip,DEX and DA groups;compared with I/R,Atip and DA group,brain tissues damage was obvious reduced in DEX group,and the Caspase3 activity,brain cell apoptosis index,the protein levels and mRNA expression of p-JNK,Caspase12,CHOP in DEX group were significantly lower,and GRP78 expression increased significantly (P ＜ 0.01).Comparisons among I/R,Atip and DA groups,there were no significant differences in degree of brain injury,Caspase3 activity,brain cell apoptosis index,the protein levels and mRNA expressions of p-JNK,Caspase12,CHOP (P ＞ 0.05),while the expression of GRP78 in DA group was significantly increased (P ＜ 0.01).Conclusion DEX can effectively relieve the brain injury induced by lung I/R in mice,which may be associated with stimulation of α2 adrenergic receptor and inhibition of excessive endoplasmic reticulum stress response and reducing brain cell apoptosis.

AIM: To establish a method for quantitation of cefepime and avibactam in M-H broth, and applicated in the in vitro dynamic PK/PD model. METHODS: The cefepime was also determined using the high-performance liquid chromatography method (HPLC), the avibactam was also determined using the liquid chromatography-mass spectrometry (LC-MS/MS), an in vitro dynamic PK/PD model was established to study the PK/PD relationship of cefepime/avibactam against carbapenem resistant Klebsiella pneumoniae (CRKP). RESULTS: The linear ranges of cefepime and avibactam were good at (0.5-20) and (0.1-25) μg/mL (r=0.999), and the lower limit concentrations were 0.5 and 0.1 μg/mL. The extraction recoveries of cefepime and avibactam in M-H broth were 88.0%-101.7% and 90.9%-95.2%, the relative standard deviation of intra-day precision and inter-day precision were less than 5.2%. The concentration-time curves were well simulated by the PK/PD model. All observed concentrations in each experiment were in the range of 20% of the targeted values. For the CRKP of MIC=8 μg/mL and MIC=16 μg/mL, the colony decreased to 2.783Log10 CFU/mL and 1.325Log10 CFU/mL at the cefepime/avibactam 2.5 g q8 h administration after 24 h. CONCLUSION: The determination method of cefepime and avibactam in broth established in this study has high sensitivity and good stability. For the CRKP with MIC≤8 μg/mL,cefepime/avibactam showed that good anti-CRKP activity under routine administration in vitro dynamic PK/PD model.