Objective:To discuss the effects of bone marrow-derived mesenchymal stem cells(BMSCs)transplantation on mitophagy in the vascular dementia(VaD)rats through reactive oxygen species(ROS)/nuclear factor erythroid 2-related factor 2(Nrf2)signaling,and to clarify its mechanism.Methods:Forty-five male adult SD rats were randomly divided into sham operation group,model group,unloaded group,BMSCs group,and MSCs+ML385(Nrf2 inhibitor)group(combination group),and there were 9 rats in each group.After intraperitoneal anesthesia,the VaD models were established in all groups except sham operation group.Morris water maze test was used to detect the learning and memory abilities of the rats in various groups;HE staining was used to observe the histopathological morphology of brain tissue of the rats in various groups;Nissl staining was used to observe the changes of Nissl bodies in hippocampus region of brain tissue of the rats in various groups;transmission electron microscope was used to observe the ultrastructure of hippocampus region of the rats in various groups;fluorescence probe method was used to detect the ROS levels in hippocampus neurons in various groups;Western blotting method was used to detect the expression levels of Nrf2,heme oxygenase-1(HO-1),PTEN-induced putative kinase 1(PINK1),parkin RBR E3 ubiquitin protein ligase(Parkin),Beclin-1,ubiquitin-binding protein p62(P62),and microtubule-associated protein 1A/1B-light chain 3(LC3-Ⅱ/LC3-Ⅰ)ratio in brain tissue of the rats in various groups.Results:The Morris water maze results showed that compared with sham operation group,the escape latency of the rats in model group was significantly increased(P<0.01),while the number of crossing time and residence time were significantly decreased(P<0.01).Compared with model group,the escape latency of the rats in BMSCs group was significantly decreased(P<0.01),while the number of crossing time and residence time were significantly increased(P<0.01).Compared with BMSCs group,the escape latency of the rats in combination group was significantly increased(P<0.01),while the number of crossing time and residence time were significantly decreased(P<0.01).The HE staining results showed that hippocampus neurons of the rats in sham operation group were normal in quantity and morphology,with uniform staining and clear structure.Compared with sham operation group,the hippocampus tissue of the rats in model group showed sparse arrangement,disordered structure,reduced neuronal quantity,varied morphology,uneven staining,nuclear pyknosis,and partial neuronal necrosis.Compared with model group,the neuronal damage of the rats in hippocampus regio in BMSCs group was alleviated,with restored morphology and improved neuronal loss.Compared with BMSCs group,the neurons of the rats in hippocampus region in combination group showed irregular morphology,disordered structure,unclear cell boundaries,uneven staining,and nuclear pyknosis.The Nissl staining results showed that the hippocampal neurons in sham operation group were tightly arranged with intact morphology,obvious nucleoli,and abundant darkly stained Nissl bodies.Compared with sham operation group,the neurons in hippocampus region of the rats in model group showed pyknosis,vacuolization,and sparse Nissl bodies.Compared with model group,the BMSCs group showed reduced neuronal pyknosis,relatively intact morphology,and increased Nissl bodies.Compared with BMSCs group,the combination group showed neuronal pyknosis,loss of morphological integrity,and fragmented Nissl bodies.The transmission electron microscope results showed that mitochondria in sham operation group exhibited oval shape with intact double-membrane structure and cristae.Compared with sham operation group,the mitochondria in model group showed swelling,disrupted membranes,broken cristae,and numerous autophagosomes.Compared with model group,the BMSCs group showed improved mitochondrial structure and reduced autophagosomes.Compared with BMSCs group,the combination group showed swollen mitochondria,disrupted membranes,broken cristae,and visible autophagosomes.The fluorescence probe results showed that compared with sham operation group,the ROS levels in the hippocampus neurons in brain tissue of the rats in model group were significantly increased(P<0.01);compared with model group,the ROS levels in hippocampus neurons in brain tissue of the rats in BMSCs group were significantly decreased(P<0.01);compared with BMSCs group,the ROS levels in hippocampus neurons in brain tissue of the rats in combination group were significantly increased(P<0.01).The Western blotting results showed that compared with sham operation group,the expression levels of Nrf2 and HO-1 proteins in brain tissue of the rats in model group were significantly decreased(P<0.01);compared with model group,the expression levels of Nrf2 and HO-1 proteins in brain tissue of the rats in BMSCs group were significantly increased(P<0.01);compared with BMSCs group,the expression levels of Nrf2 and HO-1 proteins in brain tissue of the rats in combination group were significantly decreased(P<0.01);compared with sham operation group,the expression levels of Parkin,PINK1,and Beclin-1 proteins,and LC3-Ⅱ/LC3-Ⅰ ratio of the rats in model group were significantly increased(P<0.01),while the expression level of P62 protein was significantly decreased(P<0.01);compared with model group,the expression levels of Parkin,PINK1,and Beclin-1 proteins,as well as the LC3-Ⅱ/LC3-Ⅰ ratio,of the rats in BMSCs group were significantly decreased(P<0.01),while the expression level of P62 protein was significantly increased(P<0.01);compared with BMSCs group,the expression levels of Parkin,PINK1,and Beclin-1 proteins,as well as the LC3-Ⅱ/LC3-Ⅰ ratio,of the rats in combination group were significantly increased(P<0.01),while the expression level of P62 protein was significantly decreased(P<0.01).Conclusion:BMSCs can alleviate the hippocampal neuronal pathological changes and improve cognitive function in the VaD rats,and its mechanism may be related to the regulation of ROS/Nrf2 signaling pathway to inhibit mitophagy.

Objective To observe the effects of Ditan Yizhi Decoction on learning and memory ability,structure of hippocampal tissue,neuronal morphology of hippocampus,and the expression of endoplasmic reticulum autophagy-related protein FAM134B in hippocampal tissue;To explore the mechanism of its therapeutic effect on vascular dementia.Methods Totally 32 SD rats were randomly divided into sham-operation group,model group,donepezil group and Ditan Yizhi Decoction group,with 8 rats in each group.The model group,donepezil group and Ditan Yizhi Decoction group were prepared with a modified permanent ligation method of bilateral common carotid arteries to create a rat model of vascular dementia,the common carotid artery was separated in the sham-operation group,but not ligated.After modeling,the donepezil group was given donepezil hydrochloride,Ditan Yizhi Decoction group was given Ditan Yizhi Decoction,and the sham-operation group and model group were given equal volume of distilled water for gavage for 4 consecutive weeks.Morris water maze experiment was used to evaluate the learning and memory ability,HE staining and Nissl staining were used to observe the morphological changes of hippocampus,ultrastructure of hippocampal neurons was observed using transmission electron microscopy,Western blot was used to detect the protein expression of FAM134B and p-FAM134B in hippocampal tissue.Results Compared with the sham-operation group,the escape latency period was prolonged of the rats in model group,and the number of crossing the original platform and the duration of stay in the target quadrant was reduced(P<0.01),the gap between neurons in CA1 region of the hippocampus increased,the cell morphology was irregular,the boundaries were blurred,the neurons shrinked,the Nissl bodies dissolved and broke,the number decreased,the endoplasmic reticulum arrangement was scattered,mitochondria swelled and deformed,and the expressions of FAM134B and p-FAM134B protein in hippocampal tissue increased(P<0.01).Compared with the model group,the escape latency period of rats in donepezil group and Ditan Yizhi Decoction group were significantly shortened,and the number of crossing the original platform and the duration of stay in the target quadrant were increased(P<0.01),the morphology and quantity of neurons in CA1 region of the hippocampus were more regular,with a decrease in neuronal pyknosis,an increase in the number of Nissl bodies,and a reduction in dissolution and fragmentation,the swelling and deformation of the endoplasmic reticulum were restored,and the expression of FAM134B and p-FAM134B protein in hippocampal tissue increased(P<0.01).Moreover,the effects of Ditan Yizhi Decoction group were better than those of the donepezil group(P<0.01).Conclusion Ditan Yizhi Decoction can improve the learning and memory ability and the morphology of neurons in vascular dementia rats.The mechanism may related to increasing the expression and phosphorylation of FAM134B protein,thereby promoting endoplasmic reticulum autophagy.