Humic acid induces oxidative DNA damage, growth retardation, and apoptosis in human primary fibroblasts.
Humic acid (HA) has been implicated as an etiological factor of Blackfoot disease endemic in the southwest coast of Taiwan. Dysfunction of endothelial cells and vasculopathy have been proposed to explain the onset of ulcerous changes at extremities. However, little is known about the effect of HA on activities of cells in these nonhealing wounds. In the present study, we demonstrate that HA adversely affects the growth properties of fibroblasts, one of the key players in wound repair. HA treatment caused growth arrest and apoptosis in human foreskin fibroblasts (HFF). This was accompanied by a significant increase in the level of 8-hydroxy-2'-deoxyguanosine (8-OHdG) in cellular DNA. The increased fluorescence in dichlorofluorescin (H2DCF)-stained and HA-treated cells suggests the involvement of reactive oxygen species (ROS) in HA-induced biological effects. Conversely, vitamin E pretreatment, which significantly reduced the 8-OHdG formation in HA-treated cells, alleviated the growth-inhibitory and apoptosis-inducing effects of HA. These results indicate that HA initiates oxidative damages to fibroblasts, and leads to their dwindling growth potential and survival. The present study suggests that HA-induced growth retardation and apoptosis of fibroblasts may play a role in the pathogenesis of Blackfoot disease.
Cheng
Mei-Ling
ML
Graduate Institute of Medical Biotechnology and School of Medical Technology, Chang Gung University, Kwei-san, Tao-yuan, Taiwan.
Ho
Hung-Yao
HY
Huang
Yi-Wen
YW
Lu
Fung-Jou
FJ
Chiu
Daniel Tsun-Yee
DT
D000080242:8-Hydroxy-2'-Deoxyguanosine; D017209:Apoptosis / Q000187:drug effects*; D002455:Cell Division / Q000187:drug effects*; D002478:Cells, Cultured; D004247:DNA / Q000187:drug effects*; D003849:Deoxyguanosine / Q000031:analogs & derivatives* / Q000378:metabolism; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D006812:Humic Substances / Q000494:pharmacology*; D020287:In Situ Nick-End Labeling; D018384:Oxidative Stress / Q000187:drug effects*; D017382:Reactive Oxygen Species; D014810:Vitamin E / Q000494:pharmacology
D006812:Humic Substances; D017382:Reactive Oxygen Species; D014810:Vitamin E; D000080242:8-Hydroxy-2'-Deoxyguanosine; D004247:DNA; D003849:Deoxyguanosine