Cytotoxic and antioxidant effects of the water extract of the traditional Chinese herb gusuibu (Drynaria fortunei) on rat osteoblasts.
OBJECTIVE
Gusuibu (Drynaria fortunei) is a traditional Chinese herb that has been claimed to have therapeutic effects on bone healing; however, a clinical mechanism responsible for this effect has not been identified. This study evaluated the cytotoxic and antioxidant effects of the water extract of gusuibu (WEGSB) on rat osteoblasts.


METHODS
Osteoblasts were prepared from neonatal Wistar rat calvarias and treated with WEGSB. Cell viability and alkaline phosphatase activity were determined. Intracellular reactive oxygen species were detected using the dye 2',7'-dichlorofluorescin, and mitochondrial membrane potential was detected using the dye 3,3'-dihexyloxacarbocyanine iodide and flow cytometry.


RESULTS
WEGSB at 1 and 10 micrograms/mL was not cytotoxic to rat osteoblasts, but WEGSB at 100 micrograms/mL reduced cell viability and alkaline phosphatase activity in a time-dependent manner. Although WEGSB and hydrogen peroxide did not affect the mitochondrial membrane potential of rat osteoblasts, combined treatment with WEGSB (100 micrograms/mL) and hydrogen peroxide lowered the membrane potential of mitochondria and resulted in cell death. The basal level of intracellular reactive oxygen species in rat osteoblasts was significantly suppressed by WEGSB at 10 to 100 micrograms/mL. WEGSB (10 micrograms/mL) specifically inhibited hydrogen peroxide-induced oxidative stress without an effect on nitric oxide-induced stress. Hydrogen peroxide caused concentration-dependent death of rat osteoblasts, but WEGSB significantly protected cells from hydrogen peroxide-induced death.


CONCLUSIONS
This study has shown that WEGSB at 10 micrograms/mL is not cytotoxic to rat osteoblasts in vitro, and also that the extract at 10 micrograms/microL has an antioxidant effect on these cells. The antioxidant activity of WEGSB can protect rat osteoblasts from hydrogen peroxide-induced death and may promote bone recovery under similar pathologic conditions.
Liu
H C
HC
Department of Orthopedic Surgery, National Taiwan University Hospital, Taiwan.
Chen
R M
RM
Jian
W C
WC
Lin
Y L
YL
D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D000831:Animals, Newborn; D000975:Antioxidants / Q000494:pharmacology*; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D004365:Drugs, Chinese Herbal / Q000494:pharmacology* / Q000633:toxicity; D004797:Enzyme-Linked Immunosorbent Assay; D010006:Osteoblasts / Q000187:drug effects* / Q000201:enzymology; D010946:Plants, Medicinal; D051381:Rats; D017208:Rats, Wistar; D017382:Reactive Oxygen Species / Q000378:metabolism; D012886:Skull / Q000166:cytology
D000975:Antioxidants; D004365:Drugs, Chinese Herbal; D017382:Reactive Oxygen Species; D000469:Alkaline Phosphatase