Comparative study of DNA synthesis and nucleolar organizer regions of sinusoid littoral cells in mouse regenerating liver

Variations in DNA synthesis (DNAs) and Nucleolar Organizer Regions (NORs) were studied in the littoral cell population from regenerating liver of C3HS inbred mice standardized for periodicity analysis.Immunohistochemieal detection of Bromodeoxyuridine (BrdU) with a monoclonal antibody and silver staining of NORs (AgNORs) were assessed by means of a digital image analysis system in histological sections. Tissue samples were obtained every four hours from the 30th to the 54th hours after a partial hepatectomy. The results showed, in both parameters, a gradual increment of the values during the period studied, with highest values (DNAs 107.1 ± 16.1 SE; AgNORs 77. 3± 3.4 SE) located at 16:00/54 Time of Day / Hours Post Hepatectomy (TD/HPH), which were significantly different (p <0.001) from the values of the first sample (DNAs 38.1 ± 9.5 SE; AgNORs 27.3 ± 1.0 SE) taken at 16:00/30 TD/HPH. The results of our experiment demonstrate the existence of a strong correlation of DNA synthesis measured by BrdU immunohistoehemistry andAgNORs numbers in sinusoid littoral cells from mouse regenerating liver

DNA synthesis and nucleolar organizer regions circadian rhythm in mouse regenerating liver hepatocytes

DNA synthesis and Nucleolar Organizer Regions (NORs) were studied in C3HS inbred mice standardized for periodicity analysis. Immunohistochemical detection of Bromodeoxyuridine (BrdU) incorporated into DNA with a monoclonal antibody and silver staining of NORs (AgNORs) were assessed by means of a digital image analysis system in histological sections of regenerating liver. Tissue samples were obtained at different times after hepatectomy along a circadian span. The results showed a strong correlation of values between DNA synthesis (BrdU labelling index) and AgNOR numbers, with higher counts during the activity period of animals at 00:00/38 and 04:00/42 hours Time of Day/Hours Post-Hepatectomy (TD/HPH), being the differences with other time points highly significant. Our observations demonstrate the existence of a strong correlation of DNA synthesis measured by BrdU incorporation and AgNOR numbers with a defined circadian rhythm in mouse regenerating hepatocytes.