PartI Transforming Growth Factor-? Signaling Mediates Disorganized Elastin Fiber Formation In The Newborn Mice With Chronical Hyperoxia Induced Bronchopulmonary Dysplasia PartII The Protective Effect Of Fecal Bacteria Transplantation On Neonatal Rats With

PART I TRANSFORMING GROWTH FACTOR-? SIGNALING MEDIATES DISORGANIZED ELASTIN FIBER FORMATION IN THE NEWBORN MICE WITH CHRONICAL HYPEROXIA INDUCED BRONCHOPULMONARY DYSPLASIAObjective: To explore the protective effects and mechanisms of TGF-?-neutralizing antibodies(1D11)for the newborn mice with chronical hyperoxia induced bronchopulmonary dysplasia(BPD).Methods: Postnatal 24 hours C57BL/6J mice were randomly divided into four groups: air-exposed control group,hyperoxia-exposed group(BPD group),hyperoxia-exposed PBS-treated group(02+PBS group;PBS,Phosphate buffer saline,acted as negative control group),hyperoxia-exposed 1D11-treated group(02+1D11 group).02 group,02+PBS group and 02+1D11 group were exposed to 85% oxygen,while the air group was fed in air in the same room.TGF-?-neutralizing antibodies,40?g 1D11 in 1?l PBS,5?l /g body weight,was administered by intraperitoneal injection to 02+1D11 group every day on postnatal 3d-20 d.02+PBS group was treated with the same amount of PBS at the same time.The mice were randomly sacrificed at postnatal 14 d and 21 d for the collection of the lung tissue.Using HE staining to assess the development of newborn mice lungs.The expression and distribution of elastin were assessed by immunohistochemistry(IHC).Total lung homogenate active TGF-?1 levels were measured by ELISA.The expression of protein of Smad2/3 and p-Smad2/3 were detected by western blot.The expression of m RNA and protein of TGF-?1,tropoelastin Fibulin-5 and Neutrophil elastase were detected by RT-PCR and western blot.Results: Comparing with the air group,the structure of normal alveolar disappeared,alveolar was fused and the alveolar intervals were thickened under the HE staining in the lungs from the BPD group and 02+PBS group.In the lungs from BPD group and 02+PBS group showed significant increase in the activity of TGF-?1,the expression of protein of p-Smad2/3,the expression of elastin deposited in the alveolar septum,the expression of m RNA and protein of TGF-?1,tropoelastin,Fibulin-5 and Neutrophil elastase.However,TGF-?-neutralizing antibodies(1D11)treatment could improve the development of alveoli.The 02+1D11 group showed significant decrease in the expression of elastin distributed to the secondary crest,the activity of TGF-?1,the expression of protein of p-Smad2/3,the expression of m RNA and protein of TGF-?1,tropoelastin Fibulin-5 and Neutrophil elastase.Conclusion: The TGF-?-neutralizing antibodies(1D11)has protective effects for the newborn mice with chronical hyperoxia induced bronchopulmonary dysplasia.Inhibition of TGF-? signaling pathways excessive activation and blocking the balance disorders of elastin system may account,at least in part,for the beneficial effects of 1D11 treament in the newborn mice with chronical hyperoxia induced bronchopulmonary dysplasia(BPD).PART II THE PROTECTIVE EFFECT OF FECAL BACTERIA TRANSPLANTATION ON NEONATAL RATS WITH NECROTIZING ENTEROCOLITISObjective: To observe the protective effect of fecal bacteria transplantation(FMT)for the newborn mice with necrotizing enterocolitis(NEC)and to provide experimental evidence and theoretical basis for the clinical application of FMT in the treatment of NEC.Methods: C57BL/6J Newborn Mice were randomly divided into 4 groups: normal control group,NEC model group,FMT+ normal group and FMT+NEC group.NEC newborn mice were subjected to formula gavage(a cow's milk-based formula)every 3 hours for up to 4 days as well as hypoxia(5% O2,95% N2)for 5 min in a hypoxic chamber followed by exposure to cold(24°C)for 5 minutes twice daily for 4 days.For FMT,1-day-old C57BL/6 pups were subjected to intracolonic injection once per day starting at day 1 for a total of 4 days through a catheter made from a round-tip silicone tube.The surviving animals were euthanized on day 5 and subjected to microscopic examination of H&E stained sections of terminal ileum under a phase-contrast microscope for morphological characteristics.The degree of mucosal injury was determined on histological sections of the terminal ileum by a pathologist blinded to the study conditions.Fecal samples were obtained daily from each animal and were immediately frozen for gut microbiota analysis.Results:(1)Body weight: Compared with NEC group,the body weight of mice in FMT+NEC group increased significantly,and the health condition also improved.(2)The histological structure: FMT+ normal group and normal control mice' intestinal tissue structure were similarly.In the NEC model group,the structure of the ileum and cecum was disordered,the intestinal microvilli were detached and necrosis,and the integrity of the intestinal mucosa was destroyed.In the FMT+NEC group,the tissue structure of the terminal ileum and cecum was significantly improved,the mucosal damage was reduced and the inflammatory cell infiltration was decreased.(3)The incidence of NEC in mice: Compared with control group,the incidence of NEC of FMT treatment group were decreased significantly.(4)The pathological scores and survival rates: Compared with the NEC group,FMT treatment group mice' pathological scores decreased significantly,and the survival rate was significantly improved.(5)Gut Microbiota Analysis: the total number of bacteria in mice significantly decreased and the diverisity of the microbial species was lower during experimental NEC,these changes were reversed with FMT.Conclusion: The C57BL/6J newborn mice model of NEC was successfully constructed.The fecal microbiota transplantation(FMT)has protective effects for the newborn mice with NEC.