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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: OBJECTIVE, METHODS, RESULTS. Meshes: Aminoquinolines, Animals, Apoptosis, Biliary Atresia, Biliary Tract, Chemical and Drug Induced Liver Injury, Cholestasis, DNA Nucleotidylexotransferase, Disease Models, Animal, Gallbladder, Imiquimod, Interferon Regulatory Factor-7, Interferon-alpha, Membrane Glycoproteins, Mice, Mice, Inbred BALB C, RNA, Messenger, Rotavirus, Rotavirus Infections, Toll-Like Receptor 7, Tumor Necrosis Factor-alpha.
user
Does toll-like receptor 7 agonist induce hypoplasia of the biliary system in a neonatal mouse model? Context: Viral infections and innate immunity signaling, especially Toll-like receptor 7 (TLR7) have been implicated in the pathogenesis of biliary atresia (BA). Administration of rhesus rotavirus-type A to newborn Balb/c mice produces inflammatory obstruction of bile ducts, which resembles human BA. However, whether activation of TLR7 signaling plays a role in neonatal hepatobiliary injury remains to be investigated. TLR7 agonist, imiquimod (R837), was intraperitoneally administered to Balb/c mice within 24 hours of birth and then every other day. Morphological and histological injuries of liver and gallbladder were examined at 2 weeks. Hepatic messenger RNA expression of TLR7 signaling was studied. Terminal deoxynucleotidyl transferase 2'-deoxyuridine 5'-triphosphate nick end labeling staining was used to delineate hepatobiliary apoptosis upon TLR7 stimulation. TLR7 agonist, imiquimod, induced hypoplasia of the biliary system of neonatal Balb/c mice both in atrophic gallbladder and in paucity of intrahepatic bile ducts. There was significantly higher hepatic expression of TLR7 and downstream innate immunity-mediated interferon regulatory factor 7, interferon-α, and tumor necrosis factor-α. In addition, terminal deoxynucleotidyl transferase 2'-deoxyuridine 5'-triphosphate nick end labeling-positive cells in the liver were increased after injections of TLR7 agonist.
assistant
The results demonstrate that TLR7 activation may trigger innate immunity pathways and induce apoptosis and hypoplasia of neonatal biliary trees in Balb/c mice. The novel findings give an implication of pathogenesis of infantile cholestasis, such as BA. Final Decision: yes