Quercetin Protects Primary Human Osteoblasts Exposed to Cigarette Smoke through Activation of the Antioxidative Enzymes HO-1 and SOD-1

Abstract

Smokers frequently suffer from impaired fracture healing often due to poor bone quality and stability. Cigarette smoking harms bone cells and their homeostasis by increased formation of reactive oxygen species (ROS). The aim of this study was to investigate whether Quercetin, a naturally occurring antioxidant, can protect osteoblasts from the toxic effects of smoking. Human osteoblasts exposed to cigarette smoke medium (CSM) rapidly produced ROS and their viability decreased concentration- and time-dependently. Co-, pre- and postincubation with Quercetin dose-dependently improved their viability. Quercetin increased the expression of the anti-oxidative enzymes heme-oxygenase- (HO-) 1 and superoxide-dismutase- (SOD-) 1. Inhibiting HO-1 activity abolished the protective effect of Quercetin. Our results demonstrate that CSM damages human osteoblasts by accumulation of ROS. Quercetin can diminish this damage by scavenging the radicals and by upregulating the expression of HO-1 and SOD-1. Thus, a dietary supplementation with Quercetin could improve bone matter, stability and even fracture healing in smokers.

Smoking and Unstable Hinge Fractures Cause Delayed Gap Filling Irrespective of Early Weight Bearing After Open Wedge Osteotomy

“…The viability of human osteoblasts was reduced in a concentration-and timedependent manner; therefore cigarette smoke damages human osteoblasts through the accumulation of reactive oxygen species. 22 We did not monitor the number of cigarettes used by the smokers in our study, so no dose-related effects could be found and compared with the other studies. However, we conclude that patients should be advised to discontinue smoking to Gap filling after open wedge high tibial osteotomy with a Takeuchi type II fracture of the lateral hinge, as shown on follow-up radiographs.…”

Maturação in vitro de oócitos bovinos em meios suplementados com quercetina e seu efeito sobre o desenvolvimento embrionário

“…Como já mencionado, a quercetina é capaz de reduzir os radicais livres (Braun et al, 2011), mas esse atributo da quercetina (2µM) não propiciou aumento ou redução nos níveis de GSH nos oócitos em relação ao grupo controle. A quercetina não é precursora da síntese de GSH e, portanto, não aumentaria diretamente sua síntese.…”

Collected Research on Phytonutrients: Flavonoids

“…Quercetin has a wide range of cellular protective properties against diseases including osteoporosis, certain forms of cancer, cardiovascular diseases, hypertension, and obesity (Braun et al, 2011;Cassidy et al, 2011;Ekstro et al, 2011;Gibellini et al, 2011;Gingras & Béliveau, 2011;Khoo et al, 2010;Lam et al, 2010;Stewart et al, 2008;Yang et al, 2011). The protection of quercetin against disease development is through its antioxidative, antiproliferative, antiinflammatory, anticarcinogenic, antimutagenic, antineoplastic, and antihypertensive properties.…”

“…As an antioxidant, quercetin can scavenge the free radicals produced from cigarette smoking (Braun et al, 2011). Cigarette smoking has shown to impact bones negatively by delaying fracture healing, reducing bone density, altering bone mineral content, and progressing to osteoporosis with accumulated production of reactive oxygen species (ROS) radicals.…”

“…Cigarette smoking has shown to impact bones negatively by delaying fracture healing, reducing bone density, altering bone mineral content, and progressing to osteoporosis with accumulated production of reactive oxygen species (ROS) radicals. Braun et al (2011) studied the potential inhibitory effect of quercetin on osteolclasts. The study reported that quercetin scavenged these ROS radicals and upregulated the expression of the anti-oxidative enzymes heme-oxygenase-(HO-) 1 and superoxide-dismutase-(SOD-) 1 to diminish damages from ROS.…”