The effect of Staphylococcus aureus on apoptosis of cultured human osteoblasts.
OBJECTIVE
To investigate the effect of Staphylococcus aureus (S. aureus) on cultured human osteoblast apoptosis and the corresponding mode of action.


METHODS
Transmission electron microscopy (TEM), assessment of DNA laddering, and flow cytometry assays were used to investigate human osteoblast apoptosis following infection with S. aureus.


RESULTS
TEM examination and DNA laddering assessment indicated that S. aureus can induce cultured human osteoblast apoptosis. Flow cytometry assays showed that human osteoblast apoptosis occurs in a dose-dependent manner following infection with S. aureus. In addition, compared with under co-culture conditions, inhibition of invasion by S. aureus resulted in a 64.62% reduction in the percentage of early apoptotic cells (P < 0.01); 7.09% ± 1.21% of human osteoblasts under indirect co-culture with S. aureus at a multiplicity of infection of 250 showed an early apoptotic profile compared with uninfected controls(P < 0.01).


CONCLUSIONS
S. aureus induces cultured human osteoblast apoptosis in a dose-dependent manner. Intracellular S. aureus is mainly responsible for cultured human osteoblast apoptosis following infection; secreted soluble factor(s) of S. aureus playing a minor role in this process.
Department of Orthopaedics, the Third Affiliated Hospital of Anhui Medical University, Hefei, China.
Ren-de
RD
Ning
Xian-long
XL
Zhang
Qing-tian
QT
Li
Xiao-kui
XK
Guo
D017209:Apoptosis; D018920:Coculture Techniques; D053938:DNA Fragmentation; D005434:Flow Cytometry; D006801:Humans; D046529:Microscopy, Electron, Transmission; D010006:Osteoblasts / Q000382:microbiology*; D013211:Staphylococcus aureus / Q000472:pathogenicity*