CELLULAR AND MOLECULAR STUDY OF APOPTOSIS INDUCED BY Streptococcus sanguinis ON HeLa CELLS, IN VITRO STUDY

M.M. Suryani Hutomo, drg. Heni Susilowati M.Kes., Ph.D

2012 | Tesis | S2 Kedokteran Gigi

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Streptococcus sanguinis is oral commensal bacterium. It is known that S. sanguinis is aerob-facultative bacteria, but it also found in periodontal lesions and deep abscess that usually dominated by anaerob bacteria. This bacterium is often implicated with the pathogenesis of infective endocarditis. This species can induce cell death on some cells. The purpose of this study was to identify cell morphological change during apoptotic process and to clarify the role of caspase3 in the apoptotic mechanism induced by S. sanguinis in HeLa epithelial cells. HeLa cells were treated with 10⁷ cell/ml S. sanguinis suspension and incubated for 36 and 48 hours; while one group was left untreated as negative control. To identify the morphological changes, the cells were stained with hematoxylineeosin (HE) and were observed under phase contrast microscope. The expression of active caspase-3 , in HeLa cells was examined by immunocytochemical analysis. The results of this study showed cell shrinkage and lost contact on HeLa cells after S. sanguinis exposure. The active caspase-3 molecules were detected after 36 and 48 hours cell stimulation. Statistical analysis using One-way Anova demonstrated the significant different of active caspase-3 expressing cells between groups (p<0.05). It was concluded that S. sanguinis –induced HeLa cell death characterized by cell shrinkage and regulated by caspase-3 activation.

Kata Kunci : Streptococcus sanguinis, apoptosis, cell morphological change, caspase-3 activation.