[Effect of chromium ion and antioxidant N-acetyl-cysteine on morphology of human osteoblast-like MG63 cell line].

OBJECTIVE: The objective of this study was to evaluate the cellular morphology and ultrastructural changes of MG63 cell line exposed to salt solutions of hexavalent chromium ions which may be released from the alloys used in biomedicine, and to determine if antioxidant N-acetyl-cysteine (NAC) could reduce the cytotoxicity induced by chromium ion. METHODS: MG63 cell lines were exposed respectively to 5 micromol/L Cr6+ , 10 micromol/L Cr6+ 20 micromol/L Cr6+ or 2 mmol/L NAC F12 medium in vitro for 24 h. And also, in order to assess the ability of antioxidant NAC to protect MG63 against chromium ion-induced cellular morphology and ultrastructural changes, MG63 were preincubated with 2 mmol/L NAC for 30 min, and then cultured with 10 micromol/L Cr6+ F12 medium for further 24 h. The cellular morphology and ultrastructural features were examined by optical microscopy and transmission electron microscopy (TEM). RESULTS: Under optical microscopy, we found that MG63 cells became round and detached from the culture dishes when exposed to chromium ions. The TEM examination confirmed these optical microscopic findings. MG63 cells treated with Cr6+ had the irregular shaped nuclei, swollen mitochondria, dilation of rER and numerous large vacuoles in the cytoplasm. These cellular morphology and ultrastructural changes of MG63 cell line were noticeably reduced by the NAC (2 mmol/L) pretreatment. CONCLUSION: Cr6+ significantly destroyed the cellular morphology and ultrastructure of MG63 cell line. Antioxidant N-acetyl-cysteine can play a critical role against Cr6+-induced cell changes.