Finally, in vivo study is required to validate the in vitro results. Conclusion JDBM extracts with middle or high concentration might modulate the viability, apoptosis and necrosis of immune cells, while low concentration extract seemed to have no influence. function were observed. TNF- expression of macrophages was up-regulated by co-culture with extract in 20% concentration, but was down-regulated in the same concentration in the presence of LPS stimulation. Interestingly, the production of TNF- decreased when macrophages were cultured in middle and high concentration extracts independent of LPS. Cell viability was also negatively affected by magnesium ions in JDBM extracts, which was a potential factor affecting cell function. Our results provide new information about the impact of Mg alloy extracts on phenotype of immune cells and the potential mechanism, which should be taken into account prior to clinical applications. Introduction Nowadays, metallic biomaterials have been widely used in clinical surgeries, e.g. bone substitute and fixative devices for total hip arthroplasty and bone fracture  or vascular stents and drug-eluting scaffolds for ischemic heart disease. Among them, permanent metallic biomaterials, such as stainless steel and titanium alloy, have taken the absolutely major part because of their good performance in mechanical strengths and biocompatibility. However, the drawbacks including second surgery, chronic inflammation and in-stent restenosis have been gradually recognized during their clinical use [4, 5]. Recently, Magnesium-based biomaterials have been a research hotspot as biodegradable implant devices due to their good mechanical properties  and biodegradability . The intermediate degradation products including magnesium hydroxide (Mg(OH)2) and hydrogen gas could be completely absorbed in human body or engulfed by macrophages [8, 9]. However, the excessive biocorrosion rates of magnesium alloy raised concern about the roles Mg alloy might play in pathophysiology and toxicology at the accumulative location of body. In addition, although magnesium has been used in various clinical purposes Mouse monoclonal to GST Tag such as cerebral palsy prevention, high dose magnesium might induce hypermagnesaemia . Thus, it is necessary to evaluate biological influence of Mg-based alloy, especially in monocytes and macrophages. Monocytes and macrophages play a pivotal role in FBR triggered by implantation of biomaterials . In brief, macrophages, differentiated from recruited monocytes, are assembled at the surface of implants to ingest foreign material and recruit other cells or fuse into foreign body giant cells to participate in wound healing process . Meanwhile, macrophages can be polarized into pro-inflammatory subtype (M1) expressing IL-6,TNF- or anti-inflammatory subtypes (M2a,b,c) secreting IL-10,TGF-, once recruited to the place around the implant . Not limited Febuxostat (TEI-6720) to common characteristics of FBR, Mg-based materials have some special effects due to their biodegradable characteristics. For instances, magnesium corrosion products could exert anti-osteoclasts activity by inhibiting nuclear factor-B (NF-B) activation . In addition, macrophages may inversely interfere with the degradation process of Mg alloy through phagocytosis of second phase . Currently, little is known about the influence of Mg-based alloy on immune cells. In present study, we tested the physiochemical property of an Mg-based alloy (MgC2.1NdC0.2ZnC0.5Zr, wt %, abbreviated as JDBM) which was developed for cardiovascular stents, as well as its biological effects on monocytes and macrophages, in order to provide new insight into the clinical translation for this alloy. THP-1 human monocytic cell line and its derived macrophages were used  because of their high similarity with primary monocytes and macrophages in biological function . Methods and materials Magnesium alloy samples and extract Febuxostat (TEI-6720) preparation The detailed composition and ingot of JDBM used in this study have been described in previous studies [20,21]. Febuxostat (TEI-6720) Disc samples for the experiments with a diameter of 18 mm and a height of 2.0 mm were ultrasonic cleaned with ethanol and acetone for 10 minute and then were sterilized by exposing under ultraviolet for 1h before used. Extracts were prepared according to ISO-10993 guideline. In brief, Disc samples were immersed in cell culture medium, RPMI 1640 (Gibco TM, Invitrogen), with the surface area1/volume ratio of 1 1.25 cm2/ml for 72h (5% CO2 at 37C). After that, extracts were harvested, filtered by 0.2m filter.