The effects of dithiaden on nitric oxide production by RAW 264.7 cells

Abstract

As reported in our previous studies, dithiaden (an antagonist of histamine H1-receptor, used clinically as an anti-allergic or anti-emetic drug) in a concentration range of 5×10−5–10−4 M decreased the production of reactive oxygen species by phagocytes. In this study we investigated the influence of dithiaden on nitric oxide (NO) production by LPS-stimulated macrophages.The cell viability in the presence of 10−4–5×10−5 M dithiaden was evaluated by an ATP-test. RAW 264.7 cells (2.5×106/well) were preincubated with dithiaden for 60 mins and subsequently stimulated with 0.1 µg/ml of bacterial lipopolysaccharide. After incubating for 24 hours the NO production was determined spectrophotometrically using Griess reaction as a concentration of nitrites (the end product of NO metabolism) accumulated in the cell supernatants. The expression of inducible nitric oxide synthase (iNOS) in cell-lysates was evaluated using Western blot analysis. Scavenging properties of dithiaden against NO were evaluated amperometrically.Our data demonstrate that dithiaden in the concentration of 5×10−5 M (approved by ATP test as non toxic) caused a significant decrease in the accumulation of nitrites, and in addition, this decline was followed by a marked reduction of iNOS protein expression. Amperometrical analysis did not show any scavenging properties of dithiaden against NO.From this data it can be suggested that the inhibition effect of dithiaden on macrophage NO production is caused exclusively by the suppression of iNOS protein expression.

Macrophage responses to 316L stainless steel and cobalt chromium alloys with different surface topographies

“…However, since the NO is non‐specific, healthy cells can also be damaged during the process of pathogen removal. Therefore, an excess production of NO by macrophages can result in increased inflammatory conditions . Figure shows the amount of NO released by the macrophages on the control and alloy specimens after days‐1 and 2.…”

“…Nitric oxide (NO) released from the macrophages protects the host from infections. However, the excess production of NO for an extended period of time results in damage to the surrounding tissue and causes an inflammation . Therefore, NO has a dual role of protective as well as destructive.…”

“…However, the excess production of NO for an extended period of time results in damage to the surrounding tissue and causes an inflammation. 17,[40][41][42][43] Therefore, NO has a dual role of protective as well as destructive. Clancy et al demonstrated that the picomolar concentrations of NO may be sufficient to provide the protective role while the micromolar concentrations of NO may be damaging to the surrounding tissue.…”

“…Therefore, an excess production of NO by macrophages can result in increased inflammatory conditions. 17,[40][41][42][43] Figure 7 shows the amount of NO released by the macrophages on the control and alloy specimens after days-1 and 2. There were no significant differences in NO release levels observed between any of the control and alloy specimens on day-1.…”

Oxidative Stress and Neurodegenerative Disorders

“…The assay has been used for determination of NO scavenging activity of plant [222], biomolecules [223] and small molecules [224]. Although the Griess reaction is reliable, reproducible and convenient, and easily performed in most laboratories, the limit level of NO 2 − for detection could be 2.5 μM, and the sensitivity is dependent on the sample used.…”