[Anti-apoptosis and expression of microRNA-21 in rat myocardium during early ischemia-reperfusion injury].

OBJECTIVE: To observe the expression and anti-apoptosis of microRNA-21(miR-21) in rat myocardium during early ischemia-reperfusion injury (I/R). METHODS: Sprague-Dawley rats were randomly divided into 5 groups: a control group (transfected with rAAV9-ZsGreen by coronary injection), a miR-21group (transfected rAAV9-ZsGreen-premiR- 21 by coronary injection), a sham group (open-chest only), an I/R group (I/R), and an I/ R+miR-21 (I/R after transfected rAAV9-ZsGreen-pre-miR-21 by coronary injection). Realtime PCR was used to assess the expression level of miR-21. Immunohistochemistry and Western blot were used to determine the expression of Bcl-2, Bax, caspase-3 and Bcl-2/Bax. RESULTS: MiR-21 was increased by 4.43 times in the miR-21 group (P<0.001). MiR-21 was downregulated in the ischemia zone after I/R compared with the sham group (P<0.05), but that in the non-ischemia zone was significantly increased compared with the sham group (P<0.01). MiR- 21 expression was decreased in the I/R group compared with that in the sham group at 1 h, 2 h and 6 h after I/R (P<0.05), and it was up-regulated in the I/R+miR-21 group at the same time point compared with the I/R group (P<0.01). The expression of Bcl-2, Bax, and caspase-3 was upregulated and Bcl-2/Bax was decreased in the ischemia zone in the I/R group and I/R+miR-21 group than the sham group(P<0.05). Compared with the I/R group, the expression of Bcl-2 and caspase-3 was down-regulated and Bcl-2/Bax was increased in the ischemia zone in the I/ R+miR-21 group (P<0.05). CONCLUSION: MiR-21 expression is down-regulated and cell apoptosis is increased in rat myocardium during early ischemia-reperfusion injury. Myocardial cell apoptosis may be alleviated by miR-21 over-expression.

[Roles of periostin in proliferation and migration of vascular smooth muscle cells and the effect of atorvastatin on them].

OBJECTIVE: To investigate the expression of periostin in in vitro cultured vascular smooth muscle cells (VSMCs) induced by TGF-ß1 and the relationship between periostin expression and the migration and proliferation of the VSMCs. Further, to investigate the effects of atorvastatin on the above-mentioned processes and the molecular mechanisms of atorvastatin inhibition of TGF-ß1- induced periostin production. METHODS: Rat aorta smooth muscle cells were cultivated by the method of tissue explants adherence. Cells of generation 3 to 6 were used as the experimental system. Primary cultured rat vascular smooth muscle cells were treated by TGF-ß1 and different concentrations of atorvastatin,Y-2763 (Rho kinase inhibitor), or atorvastatin plus MVA for 24 hours. The expression of periostin was measured by RT-PCR and Western blot. A Boyden chamber assay was used to measure cell migration, and an MTT test was used to measure cell proliferation. RESULTS: Periostin expression in rat VSMCs stimulated by TGF-ß1 increased significantly (4.158 ± 0.515 vs 0.385 ± 0.031), VSMC migration(25 ± 4 vs 8 ± 2) and proliferation (0.85 ± 0.06 vs 0.32 ± 0.03) also increased significantly. Atorvastatin significantly inhibited TGF-ß1-induced periostin production in rat VSMCs, as well as VSMC migration and proliferation, in a dose-dependent manner. Rho kinase inhibitor Y-27632 significantly inhibited TGF-ß1-induced periostin production in rat VSMCs (2.082 ± 0.245). The inhibitory effect of atorvastatin on periostin upregulation induced by TGF-ß1 was reversed by mevalonate (3.838 ± 0.326). CONCLUSION: Periostin can promote rat VSMC migration and proliferation. Atorvastatin inhibition of periostin expression induced by TGF-ß1 in VSMCs may be exerted by inhibition of the production of MVA and other isoprene compounds and by blocking the Rho/Rho kinase signaling pathway.