BACKGROUNDTo date murine models of permanent focal cerebral ischemia have not been well characterized. The purposes of this paper were to compare three different permanent middle cerebral artery occlusion (MCAo) models with or without craniectomy, and to identify an ideal mouse model of permanent focal cerebral ischemia.

METHODSExperiments were performed on 45 healthy adult male Kunming mice, weighing 28 to 42 g. The animals were randomly assigned to three groups (n = 15 in every group) based on surgical procedure: MCAo via the external carotid artery (ECA), MCAo via the common carotid artery (CCA), and direct ligation of the middle cerebral artery (MCA). Each day post-ischemia, the animals were scored using an eight-grade neurological function scale, and mortality was also recorded. Seven days post-ischemia, the brains were removed for lesion size determination using triphenyltetrazolium chloride staining. Correlation analysis of lesion volume and neurological score was carried out.

RESULTSMortality in the group receiving direct MCA ligation was lowest among the three groups, and there was a significant difference between the direct MCA ligation group and the two intraluminal occlusion groups (P < 0.05). In all groups, neurological scores gradually increased with prolongation of ischemic duration, peaking after two days, then gradually decreasing. In the direct MCA ligation group, however, neurological scores were relatively stable. There was a significant correlation between infarct volume and neurological score 7 days after MCAo in every group (all r > 0.7, P < 0.05), suggesting good reproducibility of lesion volume in the three groups, but the infarct volume was more constant in the direct MCA ligation group.

CONCLUSIONThe direct ligation model of MCAo provides an optimal means of studying permanent focal cerebral ischemia, and is preferable to the models using intraluminal sutures.

Animals ; Brain Ischemia ; Disease Models, Animal ; Ligation ; Male ; Mice ; Middle Cerebral Artery ; surgery ; Random Allocation ; Reproducibility of Results

Objective To investigate the effect and possible mechanism of microRNA-26a(miR-26a)on the syn-thesis of extracellular matrix(ECM)induced by high glucose(HG)in renal tubular epithelial cells(RTECs).Methods A model of diabetic kidney disease(DKD)was constructed by inducing RTECs with HG.MiR-26a was overexpressed in HG-induced RTECs,and RT-qPCR and Western blot were used to assess the effects of miR-26a on ECM synthesis and ferroptosis-related markers in HG-treated RTECs.Ferrostatin(Fer-1)was used to inhibit ferroptosis in the DKD model,and its impact on ECM synthesis was evaluated.RT-qPCR and Western blot were performed to measure ferroptosis-related markers,and fluorescence microscopy was used to observe the intensity of reactive oxygen species(ROS).Results Compared with the control group,the expression of miR-26a decreased in HG-treated cells,while the expression levels of ECM synthesis-related indexes fibronectin and collagen Ⅰ in-creased.After overexpressing miR-26a,the HG+miR-26a group showed a significant increase in miR-26a expres-sion and a decrease in fibronectin and collagen Ⅰ expression compared to the HG group.In terms of ferroptosis,the protein and mRNA expression of SLC7A11 and GPX4 significantly decreased,the expression of TFR-1 and AC-SL4 significantly increased,and the fluorescence intensity of ROS was significantly enhanced in the HG group com-pared with the control group.Inhibition of ferroptosis in the HG+Fer-1 group resulted in significant changes in fer-roptosis and ECM synthesis-related indicators expression levels compared to the HG group.Furthermore,re-expres-sion of miR-26a in the HG+miR-26a led to significant changes in ferroptosis-related indicators expression levels and decreased ROS fluorescence intensity compared to the HG group.Conclusions In HG-induced RTECs,miR-26a inhibits the occurrence of ferroptosis,thus reducing ECM synthesis.

Objective To investigate the effect and molecular mechanism of tRF-1:30-Gln-CTG-4(tRF-1:30)on the expression of inflammatory factors in high glucose(HG)-induced renal tubular epithelial cells(RTECs).Methods RTECs were divided into the control group,the HG group,the HG+tRF-1:30 mimic group,the HG+tRF-1:30 negative control(NC)group,the HG+si-IKZF2 group and the HG+si-NC group.Real-time quantitative polymerase chain reaction(RT-qPCR)was used to detect the expression levels of tRF-1:30,tumor necrosis factor-α(TNF-α),interleukin-6(IL-6),monocyte chemoattractant protein-1(MCP-1)and IKAROS family zinc finger protein 2(IKZF2).Enzyme-linked immunosorbent assay(ELISA)was used to detect levels of TNF-α,IL-6 and MCP-1.Protein expression of IKZF2 was detected by Western blot assay.Dual-luciferase reporter assay was used to detect the targeting relationship between tRF-1:30 and IKZF2.Results The expression levels of inflammatory factors were elevated in HG-induced RTECs,and the expression level of tRF-1:30 was decreased(P＜0.05).Overexpression of tRF-1:30 significantly decreased expression levels of inflammatory factors in HG-induced RTECs(P＜0.05),and the expression level of IKZF2 was significantly increased(P＜0.05).Further knockdown of IKZF2 can inhibit the release of inflammatory factors,and the expression level of IKZF2 was down-regulated after overexpression of tRF-1:30.Double luciferase reporting experiment further verified the possible targeting relationship between tRF-1:30 and IKZF2.Conclusion Overexpression of tRF-1:30 inhibits the expression of inflammatory factors in HG-induced RTECs by target binding and negatively regulating the expression of IKZF2.

Objective To investigate the role and mechanism of zinc finger protein 281(ZNF281)in high glucose(HG)-induced epithelial-mesenchymal transition(EMT)and extracellular matrix(ECM)synthesis in renal tubular epithelial cells(RTECs).Methods HG induced RTECs were used to construct a diabetic kidney disease cell model,and cells were divided into the control group,the HG group and the mannitol group.Cell proliferation viability was detected by CCK-8.The expression of ZNF281 was knocked down in HG-treated RTECs using small interfering RNA(siRNA).HG-induced RTECs after knockdown of ZNF281 were divided into the control group,the HG group,the HG+ZNF281 siRNA group and the HG+ZNF281 vector group.Adenosine monophosphate-activated protein kinase(AMPK)was activated using AMPK agonist,acadexin(AICAR),and then cells were divided into the control group,the HG group,the HG+AICAR group and the HG+dimethyl sulfoxide group.The expression levels of ZNF281,EMT and ECM synthesis-related indexes were detected by qPCR and Western blot assay.Results Compared with the control group,the protein and mRNA expression levels of vimentin,α-smooth muscle actin(α-SMA),fibronectin(FN)and collagen Ⅰ(Col Ⅰ)were significantly higher,and the expression of E-cadherin was significantly lower in the HG group.Compared with the HG group,the protein and mRNA expression levels of EMT and ECM synthesis-related indexes were significantly changed in the HG+ZNF281 siRNA group and the HG+AICAR group.The protein and mRNA expression levels of ZNF281 were significantly reduced in the HG+AICAR group compared with the HG group.In cells co-treated with AICAR and transfected with ZNF281 plasmid,the expression levels of vimentin,α-SMA,FN and Col Ⅰ were significantly higher in the AICAR+ZNF281 group,and E-cadherin was significantly lower compared with that of the vector group.Conclusion AMPK inhibits EMT and ECM synthesis in HG-treated RTECs by negatively regulating the expression level of ZNF281.