【Abstract】ObjectiveTo construct a recombinant eukaryotic expression vector for human endostatin in order to study the inhibitory effect of liposome-mediated endostatin gene on the growth of human liver carcinoma in nude mice. MethodsHuman endostatin cDNA including IL-2 secreting peptide was cloned into eukaryotic expression plasmid pcDNA3.0 to construct recombinant plasmid pCD-sEndo. pCD-sEndo plasmid was transferred into hepatocarcinoma cell line SMMC-7721 mediated by liposome Dosper, the expression and secretion of endostatin gene was detected by RTPCR and Western blot analysis. The suspension of SMMC-7721 cells was injected subcutaneously at the back of 32 nude mice to establish the model of human liver carcinoma. The mice were divided into 4 groups randomly, and injected with Dosper+pCD-sEndo, Dosper+pcDNA3.0, Dosper and physiological brine separately. Tumor volume was measured by stages. The mice were executed after the drug had been given for 1 week, then the microvessel density (MVD) of the tumor tissue was detected with immunohistochemical method and apoptotic index of tumor cells was measured by TUNEL-stain. ResultsThe eukaryotic expression vector pCD-sEndo was successfully constructed and was confirmed by enzyme digestion and sequence analysis. Expression of endostatin gene was detected in transfected SMMS-7721 cells by RTPCR in vitro, and endostatin protein was also detected in the supernatant of transfected SMMS-7721 cells by Western blot. In vivo study, the growth of human liver carcinoma was inhibited in the group injected with endostatin gene: the average volume of tumor in this group was significantly smaller than that in other groups （P＜0.05）; the average MVD in this group was 6.2±2.5, significantly less than that in the group injected with physiological brine (32.8±6.4), Dosper （27.8±6.4）, or Dosper+pcDNA3.0 (25.5±5.5), P＜0.05. The average apoptotic index of tumor cells in treatment group, brine group, Dosper group and Desper+pcDNA3.0 group was 24.5±7.3, 7.6±2.5, 9.5±3.0 and 11.2±3.6 respectively, it was evidently higher in the treatment group than in the latter three groups. ConclusionHuman endostatin mediated by cation liposome could decrease the microvessel number of implanted human hepatocarcinoma in nude mice. It could also accelerate apoptosis of tumor cells and inhibit growth of tumor.
Objective To introduce the studies on gene therapy for peripheral arterial disease(PAD) using plasmid DNA encoding human hepatocyte growth factor(HGF) gene. Methods Recent articles including preclinical and clinical studies were reviewed. Results Intramuscular injection of human HGF plasmid DNA into rat, rabbit, dog and diabetic hindlimb ischemic models, resulted in a significant increase in capillary density, blood flow and blood pressure. but no influence on tumor growth in mice. A clinical trial wasperformed in ischemic limbs of 6 critical limb ischemic patients, the result showed that no side effect caused by gene transfer was detected in all 6 patients.The pain scale and long diameter of ischemic ulcers were reduced. Conclusion Intramuscular injection of naked HGF plasmid DNA could be a safe and potential treatment for PAD.
Objective To investigate the effect of interleukin-10 （IL-10） gene transfer on expression of CD44, selectin-E, lymphocyte function associated antigen-1 （LFA-1）, vascular cell adhesion molecule-1 （VCAM-1） in mice heart transplantation rejection. Methods Model of mice cervical heterotopic heart transplantation was set up, 96 mice were divided into three groups with random number table, control group： heart transplantation between C57 mice; transplant group： heart from BALB/C mice transplant to C57 mice; IL-10 group： IL-10 was transfected on BALB/C mice isolated heart for 1 hour, then transplanted to C57 mice. The messenger ribonucleic acid （mRNA） level expression of CD44 ,selectin-E ,LFA-1 ,VCAM-1 and IL-10 were measured by reverse transcription-polymerase chain reaction （RT-PCR） at the 5th day after transplantation. Results The mRNA level expression of CD44, selectin-E ,LFA-1 ,VCAM-1 in transplant group were significantly increased than those in control group （P〈0.01）. The mRNA level expression of CD44, selectin-E, LFA-1 ,VCAM-1 in IL-10 group were significantly decreased than those in transplant group （P〈0.01）. Conclusion IL-10 gene transfer is able to decrease the expression of CD44, selectin-E,LFA-1 ,VCAM-1 and suppress the heart transplantation rejection in mice.
To study the expression of CTLA4Ig gene in diabetic rat and the effect of CTLA4Ig on longterm survival of the pancreatic islet. The rat pancreatic islet cell and muscle cell transfected with the cDNA for CTLA4Ig packaged with lipofectin vector. We examined the expression level of CTLA4Ig gene, T lymphocyte reaction and observed the expression of CTLA4Ig cDNA in diabetic rat and the action of CTLA4Ig in longterm survival of pancreatic islet transplanted and the transplanted rats. Results: The T lymphocyte reaction from peripheral intravenous blood at seventh day after surgery, the difference between two group was significant (Ｐ＜0.05). Only 2 out of 10 recipients of the experiment group (A) at the seventh day after pancreatic islet allograft had any detectable levels of CTLA4Ig, their concentration was 14 ng/ml, and 31 ng/ml. The average time of maintaining blood glycose in normal levels of the group A after pancreatic islets graft, 14.8±12.3 days, was significantly longer than 3.6±5.1 days of the control group (B) (Ｐ＜0.05). The average survival time of the group A, 24.0±10.8 days (the longest time was 45 days), was significantly longer than 11.8±4.8 days (the longest time was 21 days) of the group B (Ｐ＜0.01). Conclusions: The muclse cells and pancreatic islets of the recipient rat was transfected with CTLA4IgcDNA packaged with lipofectin, and CTLA4IgcDNA was expressed in recipient tissue, its expressed product CTLA4Ig make pancreatic islets transplanted and recipient rat survive longer significantly.
Objective To evaluate the suitability of the biodegradable microsphere encapsulation of adenovirus as a targeting vector for gene therapy of hepatocellular carcinoma. Methods Encapsulate the recombinant adenovirus in PLG 〔poly (lactic/glycolic)〕 copolymer by the solution evaporation method, the release test and the bioactivity of viruses incorporated in vitro were studied. Results More than 19.3% of adenovirus was encapsulated in PLG microspheres. The release test shows that the adenovirus was released for more than 200 h, 50% were shed within the first 100 h, and their activity was retained. Conclusion Recombinant adenovirus can be formulated in a polymer preparation of PLG with retention of bioactivity. It may be a valuable vector for the gene therapy of liver cancer.
Clustered regularly interspersed short palindromic repeats/Cas system is a powerful genome-editing tool for efficient and precise genome engineering both in vitro and in vivo, with the advantages of easy, convenient and low cost. This technology makes it possible to simultaneously mutate multiple genes in a single fertilized egg, thus to study the gene expression, genetic interaction and gene function. Even though this method is still in its immature stage and its stability is inconclusive, making precision models of ocular diseases through genome editing may provide a positive effect to explore gene targeted therapy in genetic eye disease.
Objective To investigate the stable, high effective and low toxicity gene transfer vectors’ basics in research and clinical application.Methods Current status of hepatocytedirected gene transfer vectors were reviewed by history document and contemporary experimental advances analysis.Results Viral and nonviral vector systems could both transduce target genes to liver effectively with various transduction rates based on their corresponding biological characteristics.Conclusion Hepatocyte is the effective target for gene therapy of liverrelated genetic, neoplastic and infectious diseases, although the security needs to be further evaluated.
Gene therapy develops very rapidly during the resent years. Great prospects have been demonstrated from basic study and clinic test. However, the gene therapy in CNS is still in stage of laboratory. The research status and prospects of gene therapy in spinal cord injury (SCI) were introduced. The basic principle is to transplant certain cells genetically modified with NTFs to the site of the injuried spinal cord, then NTFs are expressed in vivo and stimulate axon regrowing. Virus vectors are usually used for gene transfer because of their high rate of transfection, and the receptor cells include fibroblast, myoblast, etc. Nowadays, gene therapy in SCI is studied in many laboratories and the problems include: 1. The ideal components of transfer gene. 2. The choice of carrier. 3. Immune reaction, and prolonged survival and persistent expression of the receptor cells in the spinal cord. If these problems could be solved, the gene therapy would become the key method in the therapy of SCI.
Objective To observe the protective effect of ultrasound microbubble contrast agentmediated transfection of brain-derived neurotrophic factor(BDNF) into the retina and visual cortex on retinal ganglion cells (RGC) after optic nerve injury. Methods A total of 88 male Sprague-Dawley (SD) rats were randomly divided into normal group (group A, eight rats), sham operation group (group B, 16 rats), control group (group C, 16 rats), eyes transfection group (group D, 16 rats), brain transfection group (group E, 16 rats), combined transfection group (group F, 16 rats). The optic nerve crush injury was induced, and then the groups B to F were divided into one-week and two-week after optic nerve injury subgroup with eight rats each, respectively. The rats in group B and C underwent intravitreal and visual cortex injection with phosphate buffered solution respectively. The rats in group D and E underwent intravitreal and visual cortex injection with the mixture solution of microbubbles and BDNF plasmids respectively. The rats in group F underwent both intravitreal and visual cortex injection with the mixture solution of microbubbles and BDNF plasmids at the same time. The ultrasound exposure was performed on the rats in group D to F after injection with the mixture solution of microbubbles and BDNF plasmids. One and two weeks after optic nerve injury, RGC were retrogradely labeled with Fluorogold; active caspase-3 protein was observed by immunohistochemistry and the N95 amplitude was detected by pattern electroretinogram (PERG). Results Golden fluorescence can be observed exactly in labeled RGC in all groups，the difference of the number of RGC between the six groups and ten subgroups were significant（F=256.30，65.18；P＜0.01）. Active caspase-3 in ganglion cell layer was detected in group C to F, but not in group A and B. The difference of the N95 amplitude between the six groups and ten subgroups were significant（F=121.56，82.38；P＜0.01）.Conclusion Ultrasound microbubble contrast agent-mediated BDNF transfection to the rat retina and visual cortex can inhibit the RGC apoptosis after optic nerve injury and protect the visual function.
OBJECTIVE: To review the research progress and medical application of nano-materials. METHODS: The literature review and comprehensive analysis, methods were used in this study. RESULTS: The Nanotechnology is a typical crossing knowledge. It could be extensively applied in the fields of novel biomaterials, effective transmission of bioactive factor; the detection of functions for all vital organ systems, vascular circulation condition, the control of repair of burn trauma wounds will be monitored by the varied methods of nano technology combined with molecular biological engineering. CONCLUSION: The application of Nanotechnology will play important roles in clinical medicine, wound repair and basic research for the traditional Chinese medicine.