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Proliferative response in experimentally injured frog lens epithelium: Autoradiographic evidence for movement of DNA synthesis towards the injury
Author(s) -
Rafferty Nancy S.
Publication year - 1967
Publication title -
journal of morphology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.652
H-Index - 74
eISSN - 1097-4687
pISSN - 0362-2525
DOI - 10.1002/jmor.1051210404
Subject(s) - thymidine , mitosis , dna synthesis , clearance , biology , epithelium , population , anatomy , intraperitoneal injection , cell division , pathology , cell , andrology , microbiology and biotechnology , dna , endocrinology , biochemistry , medicine , genetics , environmental health , urology
Abstract In order to follow the movement of cells involved in the proliferative response induced by wounding, changes in the cell population of three regions of normal and injured frog lens epithelium were studied with respect to DNA synthesis and mitosis using autoradiography following intraperitoneal injection of H‐3‐thymidine. The injured lenses comprised two groups: one subjected to labeled thymidine at 40 hours post‐injury when the proliferative response begins, the other at 72 hours when the proliferative response is at its peak. Lenses were fixed at increasing intervals after injection. The data show that a central injury initiates proliferation in a large number of cells; this response appears at first mainly among the cells in the outlying proliferative (pre‐equatorial) zone, as judged by the number of labeled nuclei and mitoses seen there in the first few hours after injection in the 40 hour preparations. At later intervals labeled cells and mitoses appear centrally adjacent to the wound. And in the 72 hour preparations, the greatest concentration of reactive cells is adjacent to the wound. There is also thinning out of labeled cells in the proliferative zone and greater dilution of exposed emulsion grains over nuclei adjacent to the wound with time, suggesting that outlying cells migrate centrally, dividing en route. However, interpretation of these data is limited by the finding that H‐3‐thymidine injected intraperitoneally into the frog is not cleared rapidly from the circulation; the serum after 24 hours retains about 20% of the radioactivity (measured by scintillation counting) present at 15 minutes post‐injection.