Salinity stress results in rapid cell cycle changes of tilapia (Oreochromis mossambicus) gill epithelial cells

✍ Scribed by Brittany D. Kammerer; Brian A. Sardella; Dietmar Kültz

• Book ID: 102337365
• Publisher: Wiley (John Wiley & Sons)
• Year: 2009
• Tongue: English
• Weight: 295 KB
• Volume: 311A
• Category: Article
• ISSN: 1932-5223
• DOI: 10.1002/jez.498

✦ Synopsis

Abstract

We have developed a technique for immunocytochemistry of fish gill cells that we used to quantify tilapia (Oreochromis mossambicus) mitochondria‐rich cells (MRC) and other gill cells (non‐MRC) within different cell cycle phases by laser scanning cytometry. Gill cells fixed on coverslips were triple stained with propidium iodide to distinguish G1 vs. G2 phases, Ser10‐phosphorylated histone H3 antibody to label mitotic cells, and Na^+^/K^+^ ATPase antibody to label MRC. These parameters were measured at 0 (control), 4, 8, 16, 24, 48, 72, and 168 hr (1 week) following exposure of freshwater (FW) acclimated fish to 2/3 seawater (SW). MRC increased mitotic activity very rapidly peaking at 8 hr following SW exposure. This change in mitotic MRC is indicative of epithelial reorganization during SW acclimation. In contrast to MRC, the proportion of non‐MRC (likely pavement cells (PVC)) in mitosis did not change significantly in response to SW exposure. Moreover, twice as many MRC were in mitosis compared with non‐MRC, suggesting that MRC turn over faster than other cell types during SW acclimation. Following the mitosis peak, MRC accumulated in G2 phase over a period of 16–72 hr post‐SW exposure. We also observed G2 arrest with similar kinetics following SW exposure in tilapia non‐MRC (likely PVC). We interpret the G2 arrest that occurs after an initial wave of transient increase in MRC mitosis as a means for conserving energy for dealing with the osmotic stress imposed during the exposure of FW fish to SW. J. Exp. Zool. 311A:80–90, 2009. © 2008 Wiley‐Liss, Inc.