Objective: To investigate the effect and mechanism of helix B surface peptide (HBSP) on myocardial ischemia reperfusion injury (MIRI) in experimental mice.
Methods: The MIRI model was established by ligation of anterior descending coronary artery of the mice for 45 min and followed by corresponding treatment at 5 min before reperfusion. A total of 64 male ICR mice were randomly assigned to 4 group:①Sham group,②MIRI group, the mice received normal saline at 5 min before reperfusion,③HBSP group, MIRI mice received HBSP at 5 min before reperfusion and④HBSP+PD98059 group, MIRI mice received PD98059 (a speciifc blocker of ERK1/2) at 20 min before reperfusion and followed by HBSP at 5 min before reperfusion.n=16 in each group, all animals were treated for 2 hours. The area of myocardial infarction (MI) was detected by TTC-EB double staining method, the myocardial apoptosis rate was examined by TUNEL method, the levels of protein expression of ERK1/2 and phosphorylation of ERK1/2 were measured by Western blot analysis.
Results: Compared with MIRI group, HBSP group presented decreased MI area, decreased myocardial apoptosis rate and increased phopsphorylation level of ERK1/2, allP<0.05. Compared with HBSP group, HBSP+PD98059 group showed decreased phopsphorylation level of ERK1/2, increased myocardial apoptosis rate and increased MI area, allP<0.05.
Conclusion: HBSP may reduce the MI area via inhibiting myocardial apoptosis and therefore, protecting the experimental mice from MIRI; the mechanism might be related to the activation of ERK1/2 pathway.

ObjectiveTo investigate the effect of iridoid glycosides from Boschniakia rossica （IGBR） on epithelial-mesenchymal transition （EMT） of HepG2 hepatoma cells induced by transforming growth factor-beta 1 （TGF-β1）. MethodsHepG2 hepatoma cells were induced by 10 μg/L TGF-β1 to construct an EMT model of hepatoma cells. The cells were divided into control group （treated with serum-free DMEM）， model group （treated with 10 μg/L TGF-β1）， and IGBR group （treated with 10 μg/L TGF-β1 and 500 mg/L IGBR）， and all cells were cultured for 48 hours. Cell adhesion assay， wound healing assay， and Transwell chamber assay were used to observe the migration and invasion abilities of cells. RT-PCR and Western blot were used to measure the mRNA and protein expression levels of E-cadherin， N-cadherin， and vimentin in cells， and Western blot was used to measure the protein expression levels of Slug， Twist1， ZEB1， p-STAT3， and STAT3. A one-way analysis of variance was used for comparison of continuous data between multiple groups， and the least significant difference t-test was used for further comparison between two groups； the independent-samples t test was used for comparison between two groups. ResultsAfter TGF-β1 induction， HepG2 cells in the model group showed long spindle-shape changes， while those in the control group showed polygonal epithelia-like changes. Compared with the model group， the IGBR group had a significant reduction in cell adhesion rate and significant inhibition of cell migration and invasion abilities （all P<0.05）， as well as significant increases in the mRNA and protein expression levels of E-cadherin （P<0.05）， significant reductions in the mRNA and protein expression levels of N-cadherin and vimentin （all P<0.05）， and significant reductions in the protein expression levels of Slug， Twist1， ZEB1， and p-STAT3 （all P<0.05）. ConclusionIGBR can inhibit TGF-β1-induced EMT process in HepG2 cells， thereby attenuating cell adhesion， migration， and invasion abilities， and it can also upregulate E-cadherin， downregulate N-cadherin and vimentin， and upregulate the protein expression of Slug， Twist1， ZEB1， and STAT3， possibly by inhibiting the STAT3 pathway to downregulate the EMT transcription factors such as Slug， Twist1， and ZEB1.