Cell proliferation was assayed by BrdU incorporation. Representative histological cross sections of explants showing the effect of LiCl at 2 mM (A), 10 mM (D), and 20 mM (G) and their respective controls: 2 mM (B), 10 mM (E), and 20 mM (H) NaCl on mesothelial cell proliferation. LiCl doses of 2 mM and 10 mM did not have significant effects on the percentage of BrdU labeled cells in the mesothelium compared to controls (2 mM and 10 mM NaCl-treated explants) (C and F, respectively). However, 20 mM LiCl treatment resulted in a significant reduction in the percentage of BrdU+ cells in the mesothelium compared to controls (20 mM NaCl-treated explants) (I). Results represent the mean ± SD, t-test, * p<0.05, n = 3 in 2mM and 10 mM LiCl, n = 3 in 2 mM and 10 mM NaCl, n = 5 in 20 mM LiCl, n = 4 in 20 mM NaCl. Cell nuclei are shown in red (DAPI) and BrdU labeled nuclei (white arrows) in green. Scale bar = 50 μm.