ABSTRACT
Objective To investigate the effects of insulin on vascular diameter of the peri -infarct region and infarct volume after cerebral infarction in mice. Methods Forty male C57/BL6j mice w ere randomly divided into a control group ( n = 5), a cerebral infarction group ( n = 15), a cerebral insulin resistance group (n = 5), and a cerebral insulin resistance infarction group ( n = 15). A model of cerebral infarction w as induced by the photochemical method. A model of cerebral insulin resistance w as induced by intracerebroventricular injection of streptozocin. Tw o -photon confocal microscope w as used to in vivo evaluate the changes of vascular diameter in the peri-infarct region at 20 min after insulin injection into the cerebelomedulary cistern. After modeling of cerebral infarction, artificial cerebrospinal fluid or insulin (10 ng/ml) w as immediately injected into the cerebelomedulary cistern, and the effect of insulin on cerebral infarct volume w as evaluated at 24 h after infarction. Results Insulin did not have significant effect on various types of cerebral vascular diameters in the normal control group, but it significantly contracted cerebral arteries ( -23.16% ±6.86% and -23.32% ±6.40%, respectively; al P <0.001) and penetrating arteries ( -15.20% ±5.51% and -16.40% ±4.27%, respectively; al P < 0.001) in the cerebral insulin resistance group and the cerebral insulin resistance infarction group, but it did not have any effect on the diameters of the cerebral veins. There w ere no significant differences in the vasoactive effects of insulin betw een the cerebral infarction group and the normal control group, as w el as betw een the cerebral insulin resistance group and the cerebral insulin resistance infarction group. Insulin significantly reduced the volume of cerebral infarction in the cerebral infarction group (9.0 ±1.0 mm3 vs.6.0 ±1.2 mm3; t = 4.294,P =0.002), and it did not have significant effect on the volume of cerebral infarction in the cerebral insulin resistance infarction group ( 12.6 ±2.3 mm3 vs.11.6 ±1.7 mm3; t = 0.782, P = 0.456). Conclusions Insulin can reduce ischemic brain injury in normal mice and can not affect the cerebrovascular diameter of the peri-infarct region. The neuroprotective effect of insulin is not significant in cerebral insulin resistance in mice, and it may be associated w ith the vasoconstrictor effects of insulin in the peri -infarct region.
ABSTRACT
Objective To examine cerebrovascular reactivity to CO2 inhalation in mice. Methods In vivo Two-Pho?ton imaging technique was used to record the reaction of cerebral cortical vessels including penetrating artery, surface vein and capillary in 5 male C57 mice after CO2 inhalation under a thinned-skull cranial window. Nitric oxide syntheses inhibitor L-NAME and Prostaglandin syntheses inhibitor Indomethacin were used to block different vasodilator pathways, respectively. Results Different mouse cortical vessels displayed different degrees of dilation to 1-minute 5%CO2 inhala?tion. The penetrating artery exhibited the most obvious dilation (45.01%±4.45%). L-NAME intervention significantly di?minished cerebravascular CO2 reactivity(P<0.05). Indomethacin significantly attenuated the dilation of artery but not capillary comparing with L-NAME intervention(P<0.05). Conclusions Different vessels react differently to CO2 inhala?tion in which postaglandins and NO signal pathways are involved.
ABSTRACT
Objective To investigate the effect of exogenous semaphorin 3A (Sema3A) on apoptosis in primary cultured rat cortical neurons and the roles of phosphoinositide 3-kinase (PI3K)/serine-threonine kinase (Akt) pathway in apoptosis induced by Sema3A.Methods Newborn Sprague-Dawley rat cortical neurons were cultured in vitro and they were identified by microtubule associated protein-2 (MAP-2) staining The cultured cortical neurons were treated with various concentrations of Sema3A (0,500,1 000,and 2 000 μg/ml) for 48hours.Neuronal survival rate was detected with CCK8 assay.Neuronal apoptosis was detected with Hoechst33342 staining and TUNEL staining.The expressions of P-Akt,Akt and Bcl-2 in cortical neurons were determined with Western blotting.Results The purity of cortical neurons culture was more than 95％.CCK8 assay showed that the survival rates of cortical neurons in the groups of 500,1 000and 2 000 μg/ml Sema3A were 80.9％ ± 5.3％,67.5％ ± 3.9％ and 50.2％ ± 4.4％ of the control group,respectively (F =165.042,P =0.000).Hoechst33342 staining showed that the apoptosis rate in the normal control group and the groups of 500,1 000and 2 000 μg/ml Sema3A were 22.4％ ± 1.2％,34.0％ ± 1.2％,39.3％ ± 1.4％ and 47.3％ ±2.3％,respectively (F =103.237,P =0.000).TUNEL staining showed that the apoptosis rate in the normal control group and the groups of 500,1 000and 2 000 μg/ml Sema3A were 23.9％ ± 1.1％,31.9％ ± 1.0％,40.1％ ± 1.5％ and 51.4％ ± 3.4％,respectively (F =103.118,P =0.000).Western blotting showed that the expressions of P-Akt (F =15.959,P =0.001) and Bcl-2 (F=18.776,P =0.001) decreased gradually,while the expression of Akt had no significant changes (F =0.590,P =0.639).Conclusions Sema3A can decrease the survival rate of the cultured cortical neurons,mainly by inducing apoptosis,and the mechanism of which might be related to the down-regulation of expressions of P-Akt and Bcl-2.
ABSTRACT
Objective To investigate the mechanisms underlying neuroprotection of silent information regulation 2 homolog 3 ( SIRT3 ) against hypoxia via preconditioning.Methods PG12 cells were randomly divided into control,hypoxic preconditioning ( Hyp),Hyp with oxygen-glucose deprivation (OGD) and OGD.MTT assay and DAPI staining were used to evaluate cellular viability.MitoSOX Red was used to measure the production of mitochondrial superoxide.The protein expression of SIRT3,PGC-1α and MnSOD were assessed by Western blot.Recombinant SIRT3 was also given to further investigate its roles in hypoxic preconditioning.Results The preconditioned PC12 cells had a higher survival rate.When expressed as a percentage of the control group,MTT values following 6 h OGD were around 51.0% in the OGD group but around 74.7% in the Hyp + OGD group ( F = 56,P ＜ 0.01).Mitochondrial ROS after Hyp was less than the OGD group.Both Hyp + OGD and OGD increased the expression of SIRT3,PGC-1α and MnSOD proteins,and these increases were greater after Hyp + OGD.Similarly,the application of recombinant SIRT3 to OGD also further increased the expression of these proteins.Conclusions Hypoxic preconditioning can protect PC12 cells against hypoxic injury.One possible mechanism of hypoxic preconditioning is via SIRT3 to upregulate PGC-la and,in turn,MnSOD to reduce generation of ROS.
ABSTRACT
Background Quality of life(QOL) refers to the person's subjective appraisal of well-being,life satisfaction,health and functional performance. For those stroke patients who cannot finish the scale themselves,we can try the proxy measurement. However,until recently no QOL scale for proxies were induced to Chinese stroke patients. The goal of this research is to translate and test the SIS 3.0 for proxy,and differences between patient and proxy scores. To translate and test the SIS 3.0 for proxy, and analyzed differences between patient and proxy scores.Methods Ten pairs of patients and their proxies were involved in the primary test. Two hundreds and thirty-three pairs were involved in the formal test. We analyzed the validity, responsiveness, reliability and feasibility of the SIS 3.0 for proxy, as well as the validity in proxy assessment. Results The feasibility was sufficient. Both Split reliability and α coefficient were more than 0.8, demonstrating SIS a reliable instrument. SIS had a good content validity with correlation coefficient more than 0.6. Good criterion validity was established by comparing the scores on various domains to standardized measures with P=0.000. Construct validity was also good as indicated by factor analysis. Proxy scores were significantly different across OHS scales which showed domain responsiveness was good. Comparison of patient and proxy responses resulted in no significant difference. Conclusions SIS for proxy is satisfactory for chinese patients. It is feasible to use a proxy respondent to answer questions on the patient's behalf.