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.