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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: Actins, Animals, Carbon Tetrachloride, Cells, Cultured, Disease Models, Animal, Electrophoresis, Agar Gel, Fluorescent Antibody Technique, Indirect, In Situ Hybridization, Kupffer Cells, Liver, Liver Cirrhosis, Experimental, Male, RNA, Messenger, Rats, Rats, Sprague-Dawley, Reverse Transcriptase Polymerase Chain Reaction, Tropoelastin, Up-Regulation.
user
Is tropoelastin expression up-regulated during activation of hepatic stellate cells and in the livers of CCl ( 4 ) -cirrhotic rats? Context: Activated hepatic stellate cells (HSC) are regarded as the principal cells synthesizing extracellular matrix components in fibrotic liver. Elastin content is increased in cirrhotic livers, but the cellular source is not known. Contribution of HSC to the production of elastin was investigated. Expression of elastin in CCl(4)-cirrhotic rat liver was studied by immunohistochemistry and in situ hybridization, liver myofibroblasts were identified in histological sections by alpha-smooth muscle actin (alpha-SMA) staining. LightCycler PCR and Northern blotting were used to detect tropoelastin mRNA in isolated HSC; tropoelastin protein was detected in the cells and in cell-conditioned medium by Western blotting. HSC, isolated from normal rat liver, displayed increasing tropoelastin mRNA expression during transdifferentiation in culture. Expression of tropoelastin mRNA was accompanied by the production of tropoelastin protein in vitro. Increased levels of tropoelastin transcripts were found in the connective tissue septa of CCl(4)-cirrhotic rats and co-localized with alpha-SMA positive cells. Immunohistochemistry demonstrated elastin presence in the septa.
assistant
HSC express tropoelastin and its expression increases during transdifferentiation to myofibroblast-like cells. Final Decision: yes