Mesothelial regeneration is not dependent on subserosal cells

It has been proposed that after mesothelial injury, resident cells within t he subserosal connective tissue proliferate, differentiate, and migrate to the serosal surface. The aim of this study was to examine the temporal and spatial changes of proliferating cells in a murine model of testicular meso thelial heating and assess the potential of submesothelial cells to reconst itute the damaged mesothelium, Histology and autoradiography were employed to determine the number of cells within the submesothelial connective tissu e, as well as the proportion of cells undergoing DNA synthesis on and benea th the injured serosa, Mesothelial cells surrounding the wound demonstrated maximal DNA, synthesis 48 h after injury (27.82+/-5.64% SEM, compared with 0.17+0.16% H-3-TdR labelled cells for resting mesothelium), whereas a sign ificant increase in proliferating submesothelial cells was not seen until d ay 4 post-injury (7.79+/-3.31% compared with 0.85+/-0.64% H-3-TdR labelled cells at day 2). Furthermore, this small number of dividing submesothelial cells must include cells other than the proposed mesothelial precursors, in dicating a very low proportion of precursor cells in the submesothelial cel l population, As large numbers of mesothelial cells were seen at the wound centre by 3-4 days after injury, it is unlikely that submesothelial cells c ontributed significantly to the repopulation of the injured mesothelium. It is hypothesized that regenerating mesothelium is more likely to originate from the surrounding uninjured mesothelial cell population. Copyright (C) 2 000 John Wiley & Sons, Ltd.