A cold atmospheric-pressure plasma, which has been widely used for biomedical applications, may potentially affect the cell cycle and cause cell apoptosis. In this paper, a human hepatocellular carcinoma cell (HepG2) is treated by a single-electrode plasma jet device. Further investigation by using flow cytometric analysis demonstrates that plasma treatment increases the percentage of apoptotic cells being associated with cell cycle arrest at the G2/M phase. Moreover, the reverse transcription polymerase chain reaction assay shows that the cyclin B1 and Cdc2 are decreased at the transcription level after plasma treatment, while the expression of the p21 Cdk inhibitor, as well as that of tumor suppressor p53, is enhanced. On the other hand, the levels of certain pro- or antiapoptotic genes are checked, and the experimental results suggest that the plasma induces apoptosis by shifting the Bax/Bcl-2 ratio to trigger HepG2 cell apoptosis. The results of the present investigation indicate that the plasma jet device may have potential therapeutic activities, such as sterilization of living tissue and tumor therapy of the postoperative treatment process.

The cold atmospheric pressure plasma, which has been widely used for biomedical applications, may potentially affect the conformation of DNA. In this letter, an atmospheric pressure plasma plume is used to investigate its effects on the conformational changes of DNA of plasmid pAHC25. It is found that the plasma plume could cause plasmid DNA topology alteration, resulting in the percentage of the supercoiled plasmid DNA form decreased while that of the open circular and linearized form of plasmid DNA increased as detected by agrose gel electrophoresis. On the other hand, further investigation by using polymerase chain reaction method shows that the atmospheric pressure plasma jet treatments under proper conditions does not affect the genes of the plasmid DNA, which may have potential application in increasing the transformation frequency by genetic engineering.

Background/Aims: Ginsenoside Rb1 (GS-Rb1) is one of the most important active pharmacological extracts of the Traditional Chinese Medicine ginseng, with extensive evidence of its cardioprotective properties. Mir-208 has been shown to act as a biomarker of acute myocardial infarction in vivo studies including man. However the impact of miR-208 on the protective effect of GS-Rb1 in hypoxia/ischemia injured cardiomyocytes remains unclear. The current study aims to investigate the target gene of miR-208 and the impact on the protective effect of GS-Rb1 in hypoxia/ischemia (H/I) injuried cardiomyocytes. Materials and Methods: Primary cultures of neonatal rat cardiomyocytes (NRCMs) was subjected to the H/I conditions with or without GS-Rb1. Cell viability was calculated by MTT assay and confirmed by flow cytometry analysis. Mir-208 was then detected by qRT-PCR. Luciferase reporter assay was carried out to detect the target gene of Mir-208. Then the NRCMs were transfected with miR-208 mimics and inhibitors to evaluate the impact on cardioprotective properties of Rb1. Results: The miR-208 expression level was clearly upregulated in the H/I treated NRCMs accompanied by the percentage of the apoptotic cells which could be reversed by GS-Rb1 pretreatment. The nemo-like kinase (NLK) mRNA and protein expression levels were decreased in H/I group measured by RT-PCR and western blotting. Luciferase activity assay was then carried out to identify that NLK may be a direct target of mir-208. MTT assay showed that miR-208 inhibitor slightly decreased the protective effect of Rb1 on the H/I impaired NRCMs. However, results showed no statistical difference. Conclusions : These findings proved that NLK was a direct target of mir-208 and miR-208 act indirectly during Rb1 protecting H/I impaired NRCMs and further researches were needed to explore the relationship that microRNAs and other signal pathways in the protective effect of GS-Rb1 on the hypoxia/ischemia injuries in cardiomyocytes.

Aim. To investigate the effect of Ginsenoside Rb1 (GS‐Rb1) on hypoxia/ischemia (H/I) injury in cardiomyocytes in vitro and the mitochondrial apoptotic pathway mediated mechanism. Methods. Neonatal rat cardiomyocytes (NRCMs) for the H/I groups were kept in DMEM without glucose and serum, and were placed into a hypoxic jar for 24 h. GS‐Rb1 at concentrations from 2.5 to 40 µM was given during hypoxic period for 24 h. NRCMs injury was determined by MTT and lactate dehydrogenase (LDH) leakage assay. Cell apoptosis, ROS accumulation, and mitochondrial membrane potential (MMP) were assessed by flow cytometry. Cytosolic translocation of mitochondrial cytochrome c and Bcl‐2 family proteins were determined by Western blot. Caspase‐3 and caspase‐9 activities were determined by the assay kit. Results. GS‐Rb1 significantly reduced cell death and LDH leakage induced by H/I. It also reduced H/I induced NRCMs apoptosis induced by H/I, in accordance with a minimal reactive oxygen species (ROS) burst. Moreover, GS‐Rb1 markedly decreased the translocation of cytochrome c from the mitochondria to the cytosol, increased the Bcl‐2/ Bax ratio, and preserved mitochondrial transmembrane potential (ΔΨm). Its administration also inhibited activities of caspase‐9 and caspase‐3. Conclusion. Administration of GS‐Rb1 during H/I in vitro is involved in cardioprotection by inhibiting apoptosis, which may be due to inhibition of the mitochondrial apoptotic pathway.