Effects of autophagy on apoptosis induced by high glucose and high lipids in cardiomyocyte cell line H9C2 / 基础医学与临床

Objective To investigate the effect of autophagy on the apoptosis of H 9C2 cardiomyocytes.Methods H9C2 cardiomyocytes were incubated with different concentrations of high glucose and high lipids ( HGHL ) for different time.The surface area of cardiomyocytes was measured after HE staining .The cell viability and apoptotic rate were measured by flow cytometry.Western blot was used to detect the expression levels of LC3Ⅱ, p62, Beclin-1,LAMP2 and cleaved caspase-3.Results After treatment with HGHL, the cells appeared hypertrophy in a concentration-and time-dependent manner , the cell hypertrophy was most obvious under the condition of HGHL(500 μmol/L,36 h)(P<0.001).Cell apoptosis increased in a concentration-and time-dependent manner, the apoptotic rate was nearly 50%under the condition of HGHL ( 500 μmol/L,36 h) ( P<0.001 ) .After treatment with HGHL for 24 h, compared with the control group , the expression of LC3Ⅱ was very significantly increased ( P<0.01) , the expression of Beclin-1 and LAMP 2 were significantly decreased ( P<0.05) , but the expression of p 62 was significantly increased ( P<0.01 ) .Compared with the control group and the intervention group , the expression of cleaved caspase-3 was significantly increased ( P<0.01 ) after 1 h of chloroquine pretreatment .Conclusions HGHL induced H9C2 cardiomyocytes hypertrophy promote H 9C2 cardiomyocytes apoptosis in a concentration-and time-dependent manner .HGHL may inhibit autophagy formation and degradation of H 9C2 cardiomyocytes at the same time , leading to abnormal autophagy accumulation of cardiomyocytes , and promote apoptosis , suggesting that inhibition of autophagy may be an important cause for promote apoptosis .

A New Approach Using Manganese-Enhanced MRI to Diagnose Acute Mesenteric Ischemia in a Rabbit Model: Initial Experience.

PURPOSE: Manganese-enhanced MRI (MEMRI) has been applied to a wide range of biological and disease research. The purpose of the study was to use MEMRI to diagnose the acute mesenteric ischemia (AMI). METHODS: The institutional experimental animal ethics committee approved this study. To optimize the dose of Mn(2+) infusion, a dose-dependent curve was obtained using Mn(2+)-enhanced T 1 map MRI by an intravenous infusion 2.5-20 nmol/g body weight (BW) of 50 nmol/L MnCl2. The eighteen animals were divided into control, sham-operated, and AMI groups. AMI models were performed by ligating the superior mesenteric artery (SMA). T 1 values were measured on T 1 maps in regions of the small intestinal wall and relaxation rate (ΔR 1) was calculated. RESULTS: A nonlinear relationship between infused MnCl2 solution dose and increase in small intestinal wall ΔR 1 was observed. Control animal exhibited significant Mn(2+) clearance over time at the dose of 15 nmol/g BW. In the AMI model, ΔR 1 values (0.95 ± 0.13) in the small intestinal wall were significantly lower than in control group (2.05 ± 0.19) after Mn(2+) infusion (P < 0.01). CONCLUSION: The data suggest that MEMRI shows potential as a diagnostic technique that is directly sensitive to the poor or absent perfusion in AMI.

Monitoring dynamic alterations in calcium homeostasis by T1-mapping manganese-enhanced MRI (MEMRI) in the early stage of small intestinal ischemia-reperfusion injury.

Manganese-enhanced MRI studies have proven to be useful in monitoring physiological activities associated with calcium ions (Ca(2+)) due to the paramagnetic property of the manganese ion (Mn(2+)), which makes it an excellent probe of Ca(2+) . In this study, we developed a method in which a Mn(2+)-enhanced T1 -map MRI could enable the monitoring of Ca(2+) influx during the early stages of intestinal ischemia-reperfusion (I/R) injury. The Mn(2+) infusion protocol was optimized by obtaining dose-dependent and time-course wash-out curves using a Mn(2+)-enhanced T1-map MRI of rabbit abdomens following an intravenous infusion of 50 mmol/l MnCl2 (5-10 nmol/g body weight (BW)). In the rabbit model of intestinal I/R injury, T1 values were derived from the T1 maps in the intestinal wall region and revealed a relationship between the dose of the infused MnCl2 and the intestinal wall relaxation time. Significant Mn(2+) clearance was also observed over time in control animals after the infusion of Mn(2+) at a dose of 10 nmol/g BW. This technique was also shown to be sensitive enough to monitor variations in calcium ion homeostasis in vivo after small intestinal I/R injury. The T1 values of the intestinal I/R group were significantly lower (P < 0.05) than that of the control group at 5, 10, and 15 min after Mn(2+) infusion. Our data suggest that MnCl2 has the potential to be an MRI contrast agent that can be effectively used to monitor changes in intracellular Ca(2+) homeostasis during the early stages of intestinal I/R injury.