BACKGROUND:Bone marrow mesenchymal stem cel transplantation for myocardial infarction becomes popularized in recent years, but transplanted cels cannot survive and proliferate under early inflammatory reaction or local ischemia/hypoxia microenvironment, eventualy hampering the therapeutic outcomes.
OBJECTIVE:To investigate the therapeutic effect of PTEN-silenced bone marrow mesenchymal stem cels on acute myocardial infarction.
METHODS:(1) Bone marrow mesenchymal stem cels from Sprague-Dawley rats were randomly assigned to receive no treatment, NCsiRNA transfection using Lipofectamin2000orPTEN siRNA transfection using Lipofectamin2000. Cel growth curves were described using MTT method to detect cel cycle using flow cytometry. (2) Thirty Sprague-Dawley rats were selected to prepare myocardial infarction models that were randomized into three groups (n=10 per group): blank control, negative control and RNAi group. Six hours after modeling, bone marrow mesenchymal stem cels transfected with nothing, NCsiRNA and PTEN siRNA were respectively injected into the infarcted center of the left ventricular anterior wal in these three rat groups. After 4 weeks, al rats were subjected to cardiac function detection using echocardiography, and the survival and proliferation of bone marrow mesenchymal stem cels in the rats were observed by fluorescence microscopy.
RESULTS AND CONCLUSION:Compared with the other two groups, a significant increase in the absorbance values at different culture time, the proportion of cels in S+G2phase, and the number ofbone marrow mesenchymal stem cels in the myocardial tissue was found in the RNAi group (alP< 0.05). Additionaly, the left ventricular ejection fraction and left ventricular shortening fraction were significantly reduced in the RNAi group than the blank control and negative control groups at 4 weeks after cel transplantation (P< 0.05). Bothin vivoandin vitroexperimental findings showed that PTEN silencing could effectively improve cel survival and proliferation in the infarcted myocardium. Moreover, in thein vivoexperiment, an overt improvement in rat’s cardiac function was achieved.

Objective To prepare a nano drug(PFOB@Lip-MMC)with liposome as the carrier,liquid perfluorooc-tyl bromide(PFOB)as core and mitomycin C(MMC)loading on the liposome shell and study its inhibitory effect on the proliferation of human pterygium fibroblasts(HPFs).Methods The thin film dispersion-hydration ultrasonic method was used to prepare PFOB@Lip-MMC and detect its physical and chemical properties.Cell Counting Kit-8,Cam-PI cell viability staining and flow cytometry were employed to detect the impact of different concentrations of PFOB@Lip-MMC on the via-bility of HPFs.DiI fluorescence labeled PFOB@Lip-MMC was used to observe the permeability of the nano drug to HPFs under a laser confocal microscope.After establishing HPF inflammatory cell models,they were divided into the control group(with sterile phosphate-buffered saline solution added),PFOB@Lip group(with PFOB@Lip added),MMC group(with MMC added),PFOB@Lip-MMC group(with PFOB@Lip-MMC added)and normal group(with fresh culture medi-um added)according to the experimental requirements.After co-incubation for 24 h,flow cytometer was used to detect the apoptosis rate of inflammatory cells,and the gene expression levels of interleukin(IL)-1β,prostaglandin E2(PGE2),tumor necrosis factor(TNF)-α and vascular endothelial growth factor(VEGF)in cells were analyzed by PCR.Results The average particle size and Zeta potential of PFOB@Lip-MMC were(103.45±2.17)nm and(27.34±1.03)mV,respec-tively,and its entrapped efficiency and drug loading rate were(72.85±3.28)％and(34.27±2.04)％,respectively.The sustained-release MMC of drug-loaded nanospheres reached(78.34±2.92)％in vitro in a 24-hour ocular surface environ-ment.The biological safety of PFOB@Lip-MMC significantly improved compared to MMC.In terms of the DiI fluorescence labeled PFOB@Lip-MMC,after co-incubation with inflammatory HPFs for 2 h,DiI fluorescence labeling was diffusely dis-tributed in the cytoplasm of inflammatory HPFs.The apoptosis rate of inflammatory HPFs in the PFOB@Lip-MMC group[(77.23±4.93)％]was significantly higher than that in the MMC group[(51.62±3.28)％].The PCR examination results showed that the gene transcription levels of IL-1 β,PGE2,TNF-α and VEGF in other groups were significantly reduced com-pared to the control group and PFOB@Lip group,with the most significant decrease in the PFOB@Lip-MMC group(all P＜0.05).Conclusion In this study,a novel nano drug(PFOB@LIP-MMC)that inhibited the proliferation of HPFs was successfully synthesized,and its cytotoxicity was significantly reduced compared to the original drugs.It has good bio-compatibility and anti-inflammatory effects,providing a new treatment approach for reducing the recurrence rate after pte-rygium surgery.