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AN AUTORADIOGRAPHIC STUDY OF THE NORMAL DECAY OF LYMPHOID CELLS IN THE MOUSE THYMUS
Author(s) -
Claësson Mogens Helweg
Publication year - 1970
Publication title -
acta pathologica microbiologica scandinavica section a pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.909
H-Index - 88
eISSN - 1600-0463
pISSN - 0365-4184
DOI - 10.1111/j.1699-0463.1970.tb02540.x
Subject(s) - feulgen stain , thymidine , population , cell , dna , biology , microbiology and biotechnology , cell cycle , staining , dna synthesis , immunology , andrology , biochemistry , genetics , medicine , environmental health
The cellular decay of thymus single cell suspensions was studied by combined nigrosin dye exclusion and 3 H‐thymidine autoradiography. Nigrosin stained, Feulgen dyed thymic cell smears were examined at intervals after injection of 3 H‐thymidine into NMRI mice aged 30–45 days. Lymphoid cells of DNA‐synthesizing as well as non‐DNA‐synthesizing populations were found to decay. The decaying cells descendig from DNA‐synthesizing cell populations took up nigrosin mainly in the premitotic phase of their generation cycle. Percentage of non‐viable DNA‐synthesizing cells (8 per cent) and the average nigrosin staining time of the DNA‐synthesizing cell population (2 hours) indicated a decay rate in this cell fraction of 4 per cent per hour. The proliferation rate of the DNA‐synthesizing cell population was found to be 10 per cent per hour. Calculations including these values gave an average DNA‐synthesizing cell cycle time of 7 hours. Throughout the experimental period of 14 days, the non‐DNA‐synthesizing cell population showed random cellular decay. However, a specific cellular decay took place 3–5 days after injection of 3 H‐thymidine, indicating a life span of approximately 4 days for many small thymocytes. The total thymic grain counts were used as a measure of organ radioactivity. The first days after injection showed massive reutilization of 3 H‐thymidine released by cell decay during this period. In conclusion, a combination of autoradiography and dye exclusion of unfixed thymic cell suspensions leads to useful kinetic parameters of thymic lymphoid cell decay in situ.