Effects Of ATP Sensitive potassium channel opener on the mRNA and pro- tein expressions of caspase-12 after cerebral ischemia-reperfusion in rats

Objective To investigate effects of K_ATP opener on the expressions of caspase-12 mRNA and protein, and to explore the role of endoplasmic reticulum （ER） stress pathway in the mechanism of K_ATP opener protecting against neuronal apoptosis after cerebral ischemia-reperfusion. Methods Two hundred rats were randomly divided into four groups： sham operation group, ischemia-reperfusion group, K_ATP opener group, and K_ATP blocker group. The middle cerebral artery occlusion （MCAO） model was established by intraluminal suture occlusion method; neuronal apoptosis was detected by TUNEL staining. The mRNA and protein expressions of caspase-12 were detected by semi-quantitative RT-PCR and immunohisto-chemical staining, respectively. Results In ischemia-reperfusion group, K_ATP opener group and K_ATP blocker group, the number of apoptotic cells and the mRNA and protein expressions of caspase-12 gradually increased following cerebral reperfusion, and reached the peak at 24 h. In K_ATP opener group, The number of apoptotic cells was significantly less than that in ischemia-reperfusion group and K_ATP blocker group at 12 h, 24 h, 48 h and 72 h （P 〈 0.05 or P 〈 0.01）; while the mRNA and protein levels of caspase-12 were significantly less than those in ischemia-reperfusion group and K_ATP blocker group at all times （P 〈 0.05 or P〈0.01）. There were no differences between the ischemia-reperfusion group and K_ATP blocker group at each time （P〉 0.05）. Conclusion K_ATP opener may protect neurons from apoptosis following the cerebral ischemia-reperfusion by inhibiting ER stress pathway.

Effects of acupuncture combined with Kaijingtongmai Decoction on ATP sensitive potassium channel related proteins Kir6.1 and Kir6.2 in myocardial infarction rats

Objective:To study the effect of combination of acupuncture and medicine on the expression of ATP sensitive potassium channel related proteins Kir6.1 and Kir6.2 in rats with myocardial infarction,and to study the possible mechanism of combination of acupuncture and medicine on the improvement of myocardial infarction,so as to provide experimental data basis for the development of new treatment methods for myocardial infarction.Methods:65 healthy male SD rats were randomly selected as the control group.The other rats were fed with high-fat food for three weeks.The rats in the control group were injected with normal saline subcutaneously,and the other rats were injected with isoproterenol hydrochloride in the same way.Through ECG comparison,40 successful Mi rats were randomly divided into model group,acupuncture group,western medicine group and acupuncture drug combination group,with 10 rats in each group.After the corresponding treatment,the ECG changes of rats in each group were observed,the pathological changes of rat cardiomyocytes were observed by HE staining,and the expression of ATP sensitive potassium channel(Kir6.1,Kir6.2)protein was detected by Western blot.Results:compared with the control group,40 experimental specimens in the experimental group showed significant changes in cardiomyocyte protein The expression of Kir6.1 and Kir6.2 increased,and the difference was statistically significant.After treatment,compared with the model group,the protein expression of Kir6.1 and Kir6.2 in cardiomyocytes of Western medicine group,acupuncture group and acupuncture drug combination group showed a downward trend,among which the decline degree of acupuncture drug combination group was the most obvious,and the difference was statistically significant.The decline degree of acupuncture group and Western medicine group was not significant,and there was no significant difference Conclusion:acupuncture combined with medicine has a significant effect on improving myocardial infarction in rats,which may be related to the expression of ATP sensitive potassium channel related proteins Kir6.1 and Kir6.2 in rat cardiomyocytes.

Effects of Iptakalim on intracellular free calcium concentration of cultured rabbit pulmonary arterial smooth muscle cells

Objective：To explore the effects of Iptakalim on intracellular free calcium concentration and on the proliferation of cultured rabbit pulmonary arterial smooth muscle cells induced by endothelin-1 （ET-1） in vitro. Methods：A cell culture model, [^3H]-thymidine（[^3H]-TdR） incorporation test and confocal microscope were used to observe proliferation and intracellular free calcium concentration（[Ca^2±]） of rabbit PASMC induced by ET-1 in vitro. Results：The value of [^3H]-TdR incorporation in ET-1 group was increased 1.468 times higher than that in control group. Iptakalim at the concentration of 10^-7mol/L, 10^-6mol/L ,10^-5 mol/L lowered [^3H]-TdR incorporation by （19.8 ± 4.6）%, （41.2 ± 9.5）%, （54.7 ± 10.1）%, respectively, compared with the value of the cells treated with ET-1（P〈 0.01）; The intracellular fluorescence intensity of PASMC in ET-1 group was increased from 73.70 ± 10.12 to 143.84 ± 28.23, significantly higher than that in control group（P 〈 0.01）; whereas with Iptakalim,the fluorescence intensity（FI） was only increased from 74.30 ± 10.20 to 86.03 ± 9.82, significantly lower than that in ET-1 group（P 〈 0.01）. Conclusion：Iptakalim inhibited proliferation of PASMC and decreased intracellular free calcium concentration of cultured rabbit PASMC induced by ET-1.

Anti-aging effects of chlorpropamide depend on mitochondrial complex-Ⅱ and the production of mitochondrial reactive oxygen species

Sulfonylureas are widely used oral anti-diabetic drugs.However,its long-term usage effects on patients’lifespan remain controversial,with no reports of influence on animal longevity.Hence,the anti-aging effects of chlorpropamide along with glimepiride,glibenclamide,and tolbutamide were studied with special emphasis on the interaction of chlorpropamide with mitochondrial ATP-sensitive K+(mito K-ATP)channels and mitochondrial complex II.Chlorpropamide delayed aging in Caenorhabditis elegans,human lung fibroblast MRC-5 cells and reduced doxorubicin-induced senescence in both MRC-5 cells and mice.In addition,the mitochondrial membrane potential and ATP levels were significantly increased in chlorpropamide-treated worms,which is consistent with the function of its reported targets,mito K-ATP channels.Increased levels of mitochondrial reactive oxygen species(mt ROS)were observed in chlorpropamide-treated worms.Moreover,the lifespan extension by chlorpropamide required complex II and increased mt ROS levels,indicating that chlorpropamide acts on complex II directly or indirectly via mito K-ATP to increase the production of mt ROS as a pro-longevity signal.This study provides mechanistic insight into the anti-aging effects of sulfonylureas in C.elegans.