RESUMO
Objective: To study the effect of wortmannin (WM), a PI3K/Akt inhibitor, on the proliferation and apoptosis of leukemia cells and the possible mechanism. Methods: Human leukemia cell line K562 was treated with different concentrations of WM. The proliferation of K562 cells was examined by MTT assay. DNA damage in K562 cells was examined by single cell gel electrophoresis assay, and apoptosis of K562 cells was detected by Annexin V-FITC/PI double-staining. The expressions of total Akt, phosphorate-Akt (p-Akt), and NF-κB p65 mRNA and protein were detected by RT-PCR and Western blotting, respectively. Results: WM inhibited the proliferation of K562 cells in a dose- and time-dependent manner, with the IC((50) value of 24 h being 25 nmol/L. WM also induced apoptosis of K562 cells in a dose-dependent manner. DNA damage in K562 cells was demonstrated by appearance of comet tail after treatment with WM, with the rate of DNA tail and the tail length being significantly higher than those in the control group (P<0.01). WM dose-dependently inhibited P-Akt and NF-κB p65, but not the total Akt, mRNA and protein expressions. Conclusion: WM can inhibit proliferation and induce apoptosis of K562 cells in a dose- and time-dependent manner, probably through down-regulation of phosphorate PI3K/Akt signal pathway and NF-κB expression.
RESUMO
Objective To observe the effects of exercise on serum adiponectin and adiponectin receptor (AdipoR) level in skeletal muscle of insulin-resistant rats. Methods A total of 30 healthy male rats were randomly divided into a control group ( NC, n = 8) and a high-fat group ( HF, n = 22), fed with normal chow and high fat diet, respectively. Eighteen weeks later, the high-fat group was randomly divided into a high-fat diet control group (HC, n = 10) and an exercise group (HE, n = 12). The HC and HE group were continually fed with high fat diet, while the HE group was administered with swimming training for 6 weeks in addition at the same time. After 24 weeks, the insulin sensitivity index was calculated, and serum adiponectin level was detected by using ELISA. The expressions of AdipoR mRNA in skeletal muscle were detected with real-time fluorescence quantitative polymerase chain reaction (PCR). Results After 18 weeks, compared to NC group, the insulin sensitivity index of HF group decreased significantly. It suggested that insulin resistance appeared in HF group. Twenty-four weeks later, compared to NC group, the ISI of HC group was significantly decreased, meanwhile the level of serum adiponectin, expression of AdipoR1 and AdipoR2 mRNA in skeletal muscle of HC group were 71.9% , 59.9% and 69.2% of those of the NC group, respectively; compared to HC group, the ISI was increased significantly by exercise, meanwhile the expression of AdipoR1 mRNA in skeletal muscle was significantly increased by 1.33 times, however the level of serum adiponectin and the expression of AdipoR2 mRNA in skeletal muscle were not altered in HE group. Conclusion Six weeks of exercise improves insulin sensitivity through increasing the expression of AdipoRI mRNA in skeletal muscle.
