ABSTRACT
Objective To explore the changes of gut microbiota in response to abdominal and pelvic radiotherapy and its potential relationship with intestinal infection.Methods Irradiation was delivered to the abdominal region of BALB/c mice,following the regular human pelvic-radiotherapy protocol,2.0 Gy/d,continuous 5 d/week.Samples of ileum tissue and the intestinal content were collected at different time points of irradiation procedure,including after 3 and 5 weeks,and at 1 week after 6 weeks of irradiation.Quantitative RT-PCR was used to measure the mRNA level of antimicrobial peptides and pro-inflammtory factors.Bacterial translocation was determined by PCR.The gut microbiota was characterized by the denaturing gradient electrophoresis assay.Results The expressions of cryptdin-1 and cryptdin-4 were decreased after 3 weeks of irradiation and at 1 week after 6 weeks of irradiation(t =-7.43,-3.54,-4.72,-4.27,P ＜ 0.05),while they were significantly increased at the 5 weeks of radiation (t =6.15,5.75,P ＜ 0.05).The diversity index and richness of gut microbiota after 3 or 5 weeks irradiation were significantly decreased (t =-3.49,-4.19,-3.44,-4.97,P ＜ 0.05).The gut microbiota dysbiosis of the irradiated mice was characterized with the decrease of probiotics of Lactobacillus and the increasing of opportunistic pathogen of Escherichia coli,Shigella flexneri,et al.Bacterial translocation episodes were more frequently in the irradiated mice than that of control animal.The mRNA levels of IL-1β、IL-6 and TNF-α were significantly increased after 3 or 5 weeks of irradiation (t =4.85,6.16,7.71,4.60,4.86,5.97,P ＜ 0.05).Compared with the control,the expression levels of IL-1β and TNF-α at the 1 week after 6 weeks of irradiation ending was also obviously enhanced (t =3.67,5.88,P ＜0.05).Conclusions Pelvic radiotherapy can induce abnormality of enteric antimicrobial peptides and may result in gut microbiota dysbiosis.The disturbed gut microbial flora may further trigger an incurrence of bacterial translocation and enteritis.Therefore,the gut microbiota may be a potential interfering target to alleviate radiotherapy adverse effect.
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Objective To assess the distribution of recombinant fusion protein dTMP-GH in mice and to determine whether it is of tar-geted distribution characteristics. Methods A laboratory scale preparation of dTMP-GH recombinant fusion protein was obtained. Protein dT-MP-GH was labeled with radioactive 125 I,then mice were sacrificed at 5 min,15 min,30 min,1 h,2 h,4 h,8 h,12 h,24 h after tail vein injec-tion of 125 I-dTMP-GH at a dose of 100 μg/kg,and the organs and tissues ( heart,liver,spleen,kidney,bone and thyroid) were collected for radioactive counting. Results Preparation of purified ( >98%) dTMP-G was obtained. 125 I labeling rate was 71. 53%,radiochemical purity was 96. 53%,and specific activity was 0. 22 MBq/μl. 30 min after tail vein injection of 125 I labeled dTMP-GH,radioactivity accounted for 10% of the total injected in femoral,and metabolism was carried via liver and kidney over time. Conclusion Fusion protein mainly distribu-ted in bone marrow via tail vein injection in mice,which expressed that dTMP-GH has the characteristics of selective distribution in bone mar-row tissue.
ABSTRACT
Objective To fulfill high-efficient expression of rTMP-GH,a recombinant fusion protein of thrombopoietin mimetic peptide and human growth hormone,in Pichia pastoris.Methods cDNA fragment coding for rTMP-GH was amplified by PCR,and subsequently cloned into the expression vector pPIC9K.The linearlized plasmid pPIC9K-rTMP-GH was transformed into Pichia pastoris GS115 cells and screened in MD/MM plates under pressure of G418.The recombinant fusion protein rTMP-GH was identified by Western blotting,and its biological activity was analyzed by its ability on colony formation of megakaryoblasts.Results The pPIC9K-rTMP-GH expression plasmid was successfully constructed.GS115 cells with high expression of rTMP-GH was screened out,and the rough purified rTMP-GH showed promotive effect on megakaryoblast colony formation.Conclusion High-efficient expression of rTMP-GH in Pichia pastoris is achieved.
ABSTRACT
Objective To investigate the effects of rTMP-GH, a recombinant fusion protein of thrombopoietin mimetic peptide (TMP) and human growth hormone (GH), on the proliferation and thrombocytopoiesis of cultured megakaryocytes. Methods After being treated with 100 ng/ml of rTMP-GH for 7 d, Dami cells, a kind of megakaryocyte cell line, were analyzed by observing the numbers of colony forming unit. Meanwhile, Western blotting and RT-PCR were applied to detect the expression changes of globin transcription factor-1 (GATA-1), which is a main regulator of thrombocytopoiesis in megakaryocytes. Results The numbers of colony forming unit were markedly increased in cultured Dami cells incubated with rTMP-GH. Compared with normal control and GH treatment groups, both the mRNA and protein levels of GATA-1 were up-regulated significantly in Dami cells treated with rTMP-GH. Conclusion rTMP-GH has a strong ability to promote the proliferation and thrombocytopoiesis of megakaryocytes.