Wound repair in rat tracheal epithelium. Division of G1 and G2-arrested cells following injury

R. E. Gordon, B. P. Lane

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


The response of the tracheal epithelium to injury includes mitotic activity. If damage is minor, the residual noncycling cells within the lesion divide to replenish the population, while in severe denuding injuries, cells at the wound margin divide and migrate to repopulate the area. We subjected the tracheal lining to a mild form of trauma. This model, which avoids the complicating cell migration characteristic of healing of severe wounds, was used to explore (1) which cell types respond to such injury; (2) in which cell cycle phase the responding cells resided prior to injury; (3) the size of the subpopulations of cells; and (4) the position in the cell cycle to which they return after dividing. During regeneration, the residual cells showed two separate waves of DNA synthesis and two peaks of mitosis. Double label autoradiography revealed that the cells in the first wave of S were not the same as those in the second. Cells which incorporated tritiated thymidine at 22 hours underwent cell division and then differentiated. This establishes that these cells entered the cell cycle in G1 and after one complete cycle were arrested in G1. Cells which incorporated tritiated thymidine at 39 hours did not show any further mitotic or DNA synthetic activity. However, a small percentage of cells, corresponding to the numbers which synthesize DNA at 39 hours, were observed to divide at approximately 7 hours after mild mechanical injury. This division precedes any DNA synthesis. If cells labeled at 39 hours were stimulated to divide at a later time, some cells responded and participated in the early mitotic peak, suggesting that a second population of cells in the normal epithelium is arrested in G2, and after dividing, its progeny are again arrested in G2.

Original languageEnglish
Pages (from-to)616-621
Number of pages6
JournalLaboratory Investigation
Issue number6
StatePublished - 1980
Externally publishedYes


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