G1-DEPENDENT
MECHANISM OF HYPOXIC-TOLERANCE OF NEONATAL PIG’S RENAL TUBULAR EPITHELIAL
CELLS
Shen Qing, Yao Yujia, Wang Zheng, Chen Qiang,
Tan Weidong
Second Affiliated Hospital, West China Medical
Center, Sichuan University, Chengdu, China
Objective: The subject
is to investigate G1-phase dependent mechanism of
hypoxic-tolerance of neonatal renal tubular epithelial cells (RTEs).
Methods: Neonatal
pig’s RTEs were synchronized by the excess thymidine block technique.G1-phase
cells were harvested and divided into two groups (ischemic-cell model in
DME/F-12 with 10μM CN for 1 hour and
preventing HSP27/70 from dephosphorylation in cantharidin) which involved
in pre-ischemia and post-ischemia for 0/60/120/180/240 minutes, and set up
normal control group at the same time .To control ischemic-cell model,
intracellular ATP concentration was determined by capillary
electrophoresis, F-actin structures rearrangements by coomassie stain and
morphological by electron microcopy.Both intracellular HSP27, HSP70 and DNA
fluorescence histograms of each time of three groups were determined by
western blot and flow cytometry, respectively.
Results: (1) Both HSP27 and HSP70 are abundant in G1-phase than other
cell-phases; (2) The number of
hypodiploid cells in hypoxic-injuried group (10.4%, 14.2%, 21.2%,
22.3%, 23.1%) was significantly higher than that of preventive group (5.5%,
8.1%, 9.1%, 9.2%, 9.0%) at post-ischemia 0/60/120 /180/240 minutes,
respectively; (3) In the ischemic group, G1 period (S-phase
cells were about 20.4% at post-ischemia 240 minutes) was two hours longer
than that of the preventive group (S-phase cells were about 22.5%, 46.2%,
87.7% at post-ischemia 120/180/240 minutes, respectively); (4) Western blot
results showed that both HSP27 and HSP70 were not significantly changed at
each term of three groups.
Conclusion: (1) G1-phase dependent mechanism of hypoxic-tolerance of
neonatal pig’s RTEs is correlated with HSP27/70 abundance at this period; (2) It plays a key
role that Preventing HSP27/70 from dephosphorylation for compensatory
neonatal pig’s RTEs hyperplasia to hypoxic-injury.