MicroRNA Silencing PC-MSG Gene In SD Rats With PCP

Objective To evaluate the effects of the treatments of the recombinantplasmid comtaining the microRNA of the upstream conserved sequence ofthe major surface glycoprotein gene on the SD rats infected with PCP(Pneumocystis carinii pneumonia, PCP) via tail vein injection.Method Immuosuppressed experimental SD rats models with PCPwere established.25well-established SD rats were divided into5groupsrandomly, five of which were under the treatment of the microRNAcontaining MSG-UCS gene PC interference series expression vectorpcDNA via tail vein injection （M group）, five of which wereadministered orally with sulpha drug(H group), five of which were nottreated (C1group), five of which were treated by the tail vein injection ofvect (C2group),5of which were treated by the tail vein injection ofphysiological saline only. After a week, the numbers of PCs in the lungs ofthe rats were counted by oil immersion lens using Giemsa staining, IL-10and IFNγ in the SD rats serum were detected by ELISA, the pathologicalchanges in lungs were observed by light microscope using hematoxylin-eosin(HE) staining, and the mRNA expressions of MSG-UCSwere examined by RT-PCR, the ultramicrostructural changes of PCs wereinvestigated by scanning electron microscope.Results The numbers of PCPs in the lungs of the rats in M group andin H group were significantly less than control group (C1-3) by Giemsastaining (P<0.05). The pathological changes in lungs in M group and in Hgroup were less seriously than control group (C1-3) by HE staining. Thelevels of IL-10and IFN-γin M group were not significantly different in Hgroup （p>0.05）, the levels of IL-10in M group and in H group werenotably less than in control group (C1-3)(p<0.05), and the levels ofIFN-γin M group and in H group were significantly more than in controlgroup (C1-3)(p<0.05). Holes of different sign appeared on PC membranejust in M group and H group by scanning electron microscope. Comparedto control group (C1-3), the mRNA expressions of PC-MSG were reducedin M group and H group (p<0.05)Conclusion The recombinant plasmid comtaining the microRNA ofthe upstream conserved sequence of the major surface glycoprotein genehas an obvious curative effect on the rats with PCP, which is a newapproach to heal the SD rats infected with PCP.