Objective To investigate whether aberrant DNA methylation of ubiquinol-cytochrome C reductase core protein 1(UQCRC1)is related to cognitive impairment caused by neonatal sevoflurane exposure.Methods A total of 94 SPF C57 mice of either sex,aged 6 d,and weighing 4～6 g,were randomly divided into 7 groups:control group(Con,n=6),sevoflurane-6 and-24 h exposure groups(Sev-6 and-24 h,n=6),control+DMSO group(Con+DMSO,n=19),control+5-aza-2'-deoxycytidine(5-AZA,methylation inhibitor)group(Con+5-AZA,n=19),sevoflurane+DMSO group(Sev+DMSO group,n=19),and sevoflurane+5-AZA group(Sev+5-AZA group,n=19).From 6 to 8 d after birth,the mice of the Sev-6 and-24 h exposure groups were exposed to 3％sevoflurane daily(with 97％oxygen,2 L/min,2 h per day),while those from the Con groups were given exposure of 100％oxygen(2 L/min,2 h per day).For the mice of the 5-AZA and DMSO groups,1 mg/kg of 5-AZA or an equal volume of DMSO was injected intraperitoneally 30 min before daily exposure.In 6 and 24 h after the last exposure to sevoflurane,6 mice from the Con,Sev-6 h,and Sev-24 h groups were euthanized for biochemical analysis,and in 24 h post-exposure,6 mice from the Con+DMSO,Con+5-AZA,Sev+DMSO,and Sev+5-AZA groups were randomly selected for biochemical analysis,while another 3 mice from above each group were also randomly selected for morphological analysis.The remaining 10 mice in these groups underwent behavioral testing(open field test,novel object test,and Y-maze test)at 30～33 d after birth to assess cognitive function,and were euthanized in 24 h after the final behavioral test.RT-qPCR and Western blotting were used to detect the hippocampal expression of UQCRC1,DNA methyltransferases(Dnmts),and methyl CpG binding protein 2(Mecp2)at mRNA and protein levels,respectively.Immunofluorescence assay was employed to observe the distribution and expression of UQCRC1 in the hippocampus.Bisulfite sequencing PCR(BSP)was applied to measure the methylation in the UQCRC1 promoter region.Results Compared with the Con group,the mRNA and protein levels of UQCRC1 were down-regulated(P<0.05),and the mRNA level of Dnmts was up-regulated(P<0.05)in both the Sev-6 h and Sev-24 h exposure groups,while the methylation level in the UQCRC1 promoter region was enhanced in the Sev-24 h exposure group(P<0.05).Additionally,the Sev+5-AZA group had obviously increased mRNA and protein levels of UQCRC1(P<0.05),and notable improvement in cognitive impairment(P<0.05)when compared with the Sev+DMSO group.Conclusion Hypermethylation of UQCRC1 promoter region and thus down-regulating its mRNA and protein expression might be the main mechanism by which repeated neonatal sevoflurane exposure induces cognitive impairment later in life.

Objective To investigate the intrinsic neural mechanism of aggressive behavior in CD 1 mice.Methods CD1 mice with aggressive behavior were screened out by resident intruder test.After the aggressive conditioned pair preference was further verified,the activated brain regions of the whole brain were labeled with c-Fos,and the types of neurons activated by the aggressive behavior were analyzed by double immunofluorescence labeling.Finally,the effects of activity of these neurons regulated by optogenetics on aggressive behavior were observed.Results The c-Fos screening revealed that about 82％of the CD1 mice showed aggressive behavior.After the occurrence of aggressive behavior,the main activation occured in the medial prefrontal cortex(mPFC),and the results of immunofluorescence double labeling showed that the c-Fos positive neurons in the mPFC were mainly glutamatergic neurons.Finally,glutamatergic neurons in the mPFC could be activated by optogenetics,and the activation inhibited the aggressive behavior of CD1 mice.In contrast,optogenetics could inhibit glutamatergic neurons in the mPFC and then promote the aggressive behavior of CD1 mice.Conclusion Glutamatergic neurons in the mPFC are an important component in the regulation of aggressive behavior in CD1 mice.

Objective To explore the pharmacokinetic changes of single dose of fentanyl in rats in a simulated high-altitude and contributing factors.Methods Thirty-six healthy female SD rats(6～8 weeks old,250±20 g)were randomly divided into high-altitude-acute-exposure group(group A),high-altitude-chronic-exposure group(group S)and control group(group C)through random number table,with 12 rats in each group.The group A and S were housed in a low-pressure chamber simulating the high altitude of 5000 m above sea level for 3 and 30 d respectively,and the group C was housed out of the chamber(at an altitude of 300 m).A single dose of fentanyl was administered through the femoral vein to 6 rats randomly selected from each group.Liquid chromatography tandem mass spectrometry(LC-MS/MS)was used to detect blood concentrations of fentanyl and WinNonlin 8.2 software was used to calculate the pharmacokinetic parameters,while blood samples were taken through the femoral artery before and in 1,2,4,8,15,30,60,120 and 180 min after administration.The remaining 6 rats were ultrasonographically assessed for portal vein internal diameter(PVD),peak flow velocity(PVV)and blood flow(PVF),and liver tissues were collected for CYP3A1 protein content assay.Results The blood drug concentrations of fentanyl in the group A and group S were significantly lower than those in the group C at 60,120,and 180 min(P=0.002,P＜0.001,P= 0.001).Compared with the group C,the clearance rate(CL)of the group A was increased by 54.06%(P=0.021),and the mean residence time(MRTlast)was shortened by 24.21%(P=0.033);CL of the group S was increased by 50.10%(P=0.041),the area under the concentration-time curve(AUC0-t,AUC0-∞)and MRTlast were reduced by 18.92%(P=0.039),27.54%(P=0.018)and 33.61%(P= 0.004),respectively.PVD and PVF in the group S increased by 10.87%(P=0.006)and 42.50%(P= 0.006)when compared with the group C.The CYP3A1 protein content in the group A was 28.74%,which was higher than that in the group C(P=0.048).Conclusion Fentanyl is cleared significantly faster after a single dose in rats in simulated high-altitude,which may be related to the increased liver blood flow and increased CYP3A1 protein expression in liver.

Objective To observe the expression of pannexin1(PX1) in the dorsal horn of spinal cord in model ratwith neu-ropathipain afteselective ligation of sciatinerve branche.Method50 male SD ratwere randomly divided into 3 group,inclu-ding the control group(Wgroup ,n= 10) ,sham operation group(sham group ,n= 10) and sciatinerve branch selective injury group(SNI group ,n=30) .30 ratwere killed on postoperative 3 ,5 ,7 ,14 d and the lumbasegmenof the spinal cord wataken fodetecting the expression of PX1 by using Western blo.Othe20 ratwere killed on 7 d afteSNI and the expression of glial fibril-lary acidiprotein(GFAP) in the spinal cord wadetected with immunohistology .Among them ,10 ratin the SNI group were trea-ted with intrathecal intubation before operation and administrated with saline 20 μL ocarbenoxolone(CBX) 20 μL by intrathecal injection on postoperative 7 d fodetermining the expression of GFAP by the immunohistology .ResultThe expression of PX1 in the SNI group waincreased and enhanced with time ,which wasignificantly highethan thain the Wgroup and the sham group (P＜0 .05);the GFAP expression on 7 d in the SNI group waobviously increased compared with the Wgroup and the sham group(P＜0 .05);afteintrathecal injection of CBX ,the expression of GFAP wasignificantly decreased compared with thain the normal saline group(P＜0 .05) .No statistically significandifferencein the expression of PX1 and GFAP were found in the Wgroup and the sham group .Conclusion PX1 may be involved in the activation of astrocyte,prompting thaPX1 playan importanrole in the neuropathipain caused by the peripheral nervel injury .