<p><b>OBJECTIVE</b>To investigate the inhibitory effect of salidroside (Sal) on pulmonary microvascular
endothelial cell (HPMEC)
apoptosis induced by simulated
microgravity and its mechanism.</p><p><b>
METHODS</b>
Human pulmonary microvascular
endothelial cells cultured
in vitro were divided into
control group,
clinorotation group and
clinorotation+Sal pretreatment groups.
Microgravity was simulated by
clinorotation. The apoptotic rate of HPMECs was detected by
flow cytometry using
Annexin V-
FITC staining, and the expressions of bcl-2, bax, and
caspase-3 at the
mRNA and
protein levels were determined by
real-time PCR and
Western blotting, respectively.</p><p><b>RESULTS</b>A 72-h
clinorotation significantly induced
apoptosis in HPMECs.
Real-time PCR results demonstrated a significantly lowered bcl-2 but increased bax and
caspase-3 mRNA expressions in
clinorotation group as compared with those in the
control group.
Western blotting showed that
clinorotation inhibited the
protein expressions of PI3K and p-AKT and increased
caspase-3 protein expression. Salidroside significantly inhibited the
cell apoptosis, reversed the expressions of Bcl-2 and Bax, and attenuated the decrease in the
protein expression of PI3K and
phosphorylation level of AKT. Salidroside also antagonized the activation of
caspase-3.</p><p><b>CONCLUSION</b>PI3K/AKT pathway and
caspase 3 are involved in the
apoptosis of HPMVECs induced by
clinorotation, and the effect of
clinorotation can be reversed by salidroside, suggesting the potential value of salidroside for application in
spaceflight.</p>