[Simvastatin prevented myocardium of diabetes rats from apoptosis through inhibition of oxidative stress].

OBJECTIVE: To investigate the protective effects and the possible mechanisms of simvastatin on myocardial injury induced by diabetes. METHODS: Twenty-four SD rats (180~220)g were randomly divided into control group (control, n=8) and modeled groups(n=16), the modeled groups were injected with streptozotocin intraperitoneally to induce diabetes. Then the modeled rats were randomly divided into diabetes mellitus group (DM group, n=8) and diabetes mellitus + simvastatin group (DM+S group, n=8). Rats in DM+S group were treated with simvastatin at the dose of 40 mg/(kg·d)by gavage for 4 weeks, and the other two groups were treated with the same amount of saline. At the end of experiments, the heart tissues were collected for further observation. The content of malondialdehyde (MDA) and the activity of superoxide dismutase (SOD) in heart tissues were measured by spectrophotometry; HE staining of rat heart slides was used to observe the pathological changes; TUNEL assay was used to determine the apoptosis index of myocardial cells in each groups; The distribution of p53 in the heart tissues was evaluated by immunohistochemistry; Western blot was used to detect the expressions of p53, p53-phospho-serine 15, Bax and Bcl-2 in the heart tissues. RESULTS: ①Compared with control group, the content of malondialdehyde (MDA) was increased while the activity of superoxide dismutase (SOD) was decreased significantly in DM group (P<0.01). After simvastatin administration, the activity of SOD was increased and the content of MDA was decreased significantly (P<0.01). ② HE staining results showed that the myocardial cells in the DM group were disorganized, with unclear morphological structure and a large number of inflammatory cells infiltration. Compared with DM group, the myocardial morphology in DM+S group was improved significantly. ③TUNEL staining results showed that the apoptosis index of myocardial cells in DM group was increased significantly compared with that of control group, and the apoptosis index was decreased significantly after the treatment of simvastatin (P<0.01).④ Immunohistochemistry showed that compared with control group,the expression of p53 in DM group was increased significantly, and was expressed in both cytoplasm and nucleus, while the expression of p53 in DM+S group was decreased and the expression of p53 in nucleus was decreased significantly (P<0.01). ⑤ The results of Western blot showed that the expression levels of p53, p53-phospho-serine15 and Bax were higher than those in control group, and the expression of Bcl-2 was lower than that in control group (P<0.01). After simvastatin administration, the expression levels of p53,p53-phospho-serine 15 (P<0.01) and Bax were decreased significantly (P<0.05) and the expression of Bcl-2 was increased (P<0.05). CONCLUSIONS: Simvastatin exerted protective effects on myocardial injury caused by diabetes through improving the abnormal morphological changes of diabetic myocardium, alleviating oxidative stress and inhibiting apoptosis of myocardial cells. The mechanism is related to the regulation of apoptosis pathway mediated by p53.

[Protective effect of simvastatin on kidney of rats with diabetes mellitus and the possible mechanism].

OBJECTIVE: To observe the protective effect of simvastatin on renal injury in diabetic rats and to explore the possible molecular mechanism. METHODS: Twenty-four SD rats were randomly divided into normal control (NC) group (n=8) and modeling group (n=16).The rats in modeling group were injected with streptozotocin intraperitoneally at a dose of 55 mg/kg to establishing diabetic rat model. After diabetic ratmodel established successfully, the diabetic rats were randomly subdivided into diabetes mellitus (DM) group and diabetes mellitus + simvastatin (DM+Sim) group (n=8).Rats in DM+Sim group were given simvastatin at a dose of 40 mg/kg by oral gavages, once a day for 4 weeks. Morphological changes and interstitial fibrosis of kidney were observed by histopathological method. The expressions of relative protein in endoplasmic reticulum stress, inflammatory molecules in renal tissues and cells apoptosis were detected by molecular biology method. RESULTS: ① Compared with NC group, the pathological changes of glomerulus and tubulointerstitium were obvious, and the collagen fibers were obviously erythrophilous and unevenly distributed in DM group. Compared with DM group, the morphological changes and fibrosis were significantly improved in DM+Sim group. ② The expressions of GRP78, p-IRE1α, NF-κB p65 and MCP-1 in DM group were significantly higher than those in NC group (P<0.05), while the expressions of GRP78, p-IRE1α, NF-κB p65 and MCP-1in DM + Sim group were decreased (P<0.05). ③ There were a small number of apoptotic nuclei in the glomeruli and adjunctive renal tubules in NC group detected by TUNEL assay, while there were a large number of apoptotic nuclei in DM group (P<0.01). The number of apoptotic nuclei was decreased significantly in DM+Sim group (P<0.01). CONCLUSIONS: Morphologicalchanges and fibrosis of renal tissue are improved obviously, and the number of apoptotic cells is decreased significantly after administration of simvastatin in diabetic rats. Simvastatin exertsthe protective effect on diabetic nephropathy by inhibiting endoplasmic reticulum stress and NF-κB inflammatory signaling pathway, and reducing renal cell apoptosis.

[SR 59230A on the expression of MicroRNAs in myocardium of heart failure rats].

OBJECTIVE: To investigate the effects of ß3-adrenoceptors(ß3-AR) inhibitor SR 59230A on MicroRNAs expression in rat myocardium with chronic heart failure and the related mechanisms. METHODS: One hundred male SD rats were randomly divided into sham operated group(40)and chronic heart failure(CHF)group(60). Coronary artery ligation was used to induce CHF. Then the rats in CHF group were further randomly divided into CHF control group and CHF+SR 59230A group (CHF+SR). Rats in the sham group were divided into sham control group and sham+SR 59230A group (Sham+SR). The rats in Sham+SR group and CHF+SR group were treated with 1 ml SR 59230A(85 mmoL/L in 0.9% saline)twice a day for seven weeks by intraperitoneal injection, while the rats in control groups were injected with the same amount of saline for seven weeks separately. miScript miRNA PCR Arrays were used to determine the expression profile of MicroRNAs. Immunohistochemistry was used to evaluate the distribution of the related proteins in the heart tissue sections. Western blot was used to detect the expressions of nuclear factor-kappaB(NF-κB),p53 and p53-Phospho-Serine 15 in the heart. RESULTS: ①After in vivo blockade of ß3-AR by SR 59230A, there were 18MicroRNAs down-regulated in sham control group and CHF control group. Within them, 6 MicroRNAs were related to NF-κB signaling pathway, they were miR-125b-5p,miR-143-3p,miR-145-5p,miR-26a-5p,miR-30a-5p and miR-320-5p. ②Slides from the heart tissue showed that NF-κB was distributed both in nucleus and cytoplasm, while p53 in cytoplasm was more than that in nucleus in heart tissue sections. The expressions of NF-κB and p53 were higher in the CHF control group than those in the sham control group(P<0.05), but were lower in CHF+SR group than those in CHF control group(P<0.05),while they were elevated in Sham+SR group compared to the sham control group(P<0.05). ③ Compared with the sham control group, the protein expression of NF-κB p65 was increased significantly in the CHF control group (P<0.05). After treated with SR59230A in vivo,the protein expressions of NF-κB and p53-Phospho-Serine 15 were decreased significantly in CHF rats(P<0.05),while the protein expressions of NF-κB, p53 and p53-Phospho-Serine 15 proteins were increased in the sham rats (P<0.05). CONCLUSIONS: Blocking of ß3-AR improved the damaged heart in CHF rats; ß3-AR caused the change of MicroRNAs expression, and it related to NF-κB signal pathway.

[Silencing of PKG1 expression enhances the efficacy of vemurafenib against melanoma cell].

OBJECTIVE: To explore whether targeting phosphoglycerate kinase 1 (PGK1) can enhance the sensitivity of BRAFV600E mutation melanoma cells to vemurafenib. METHODS: The methods of cell biology, molecular biology and pharmacology(MTT assay, Western blot, FCM, Colongenic assay) were used in this study. RESULTS: ① Silencing of PGK1 expression increased the efficacy of vemurafenib in melanoma cells, as evidenced by greater killing in the tumor cells subjected to combined treatment of vemurafenib with siPGK1; ②The mechanism of enhanced sensitivity of melanoma cells to vemurafenib was associated with activation of apoptotic signaling pathway. CONCLUSIONS: Targeting of PGK1 may represent a novel strategy of sensitizing melanoma cells to vemurafinib.