A Comparison of Reactive Oxygen Species Generation by Rat Peritoneal Macrophages and Mast Cells Using the Highly Sensitive Real-Time Chemiluminescent Probe Pholasin: Inhibition of Antigen-Induced Mast Cell Degranulation by Macrophage-Derived Hydrogen Peroxide

Abstract

Mast cells and macrophages live in close proximity in vivo and reciprocally regulate one another’s function in various ways. Although activated macrophages possess a powerful reactive oxygen species (ROS) generating system, there is conflicting evidence regarding whether mast cells can produce ROS. We used the highly sensitive real-time chemiluminescent probe Pholasin to examine ROS release by peritoneal macrophages and mast cells isolated from OVA-sensitized rats. Macrophages stimulated with PMA (0.8 μM) or ionomycin (1 μM), but not OVA (1 μg/ml), released high-level ROS, levels of which peaked after 3–7 min and declined to baseline levels within 1 h. Superoxide was identified as the major ROS species induced by PMA but not by ionomycin. In contrast, purified mast cells stimulated with PMA released low-level ROS, which was entirely due to the contaminating (2%) macrophages, and did not release any detectable ROS in response to ionomycin or OVA at concentrations that induced degranulation. Stimulation of mixed cell populations with PMA to induce macrophage ROS release led to 50% inhibition of serotonin release from mast cells stimulated 5 min later with OVA. The PMA-induced inhibitory factor was identified as hydrogen peroxide. In conclusion, activated rat peritoneal macrophages but not mast cells produce ROS, and macrophage-derived hydrogen peroxide inhibits mast cell degranulation. The latter could be an important mechanism whereby phagocytic cells regulate mast cell activation and promote resolution of IgE-mediated inflammation.

<i>Anethum graveloens</i> Flower Extracts Inhibited a Lipopolysaccharide-Induced Inflammatory Response by Blocking iNOS Expression and NF-κB Activity in Macrophages

“…38) During inflammation, activated phagocytes such as neutrophils and macrophages generate an ROS-dependent respiratory burst, and ROS can orchestrate inflammatory responses. 40,41) Hence we also compared the LPSstimulated NO production with Anethum graveloens root and stem extracts for anti-inflammation effects. In the NO assays, the flower extract showed higher antiinflammation activity than the root and stem extracts (data not shown).…”

Effects of genistein following fractionated lung irradiation in mice

“…There are at least three potential sources of ROS within the irradiated lung, first that which is produced as a direct result of radiation, second that is generated by inflammatory cells [12,170], and third from the mitochondria because of leakage from the electron transport chain [14]. Using whole lung irradiation it is difficult to distinguish between these sources; however, previous studies in our lab using half lung irradiation of rats [27, 28, 119] showed significant DNA damage both in and out of the radiation field.…”

“…Following radiation, type I cells are damaged and lost from the alveolar surface and type II cells rapidly proliferate to reepithelialize the alveolar surface. Type II cells may also be injured by radiation and this triggers a release of surfactant [11,12]. A large number of cytokines, growth factors and cytokines regulate this response [13].…”

“…The breathing rate of mice was measured at 0, 4,8,10,11,12,13,14,16,18,20,22, 24, 28 weeks following irradiation using a whole body plethysmograph (Columbus Instruments, Columbus, Ohio). Increases in breathing rate have been previously shown during pneumonitis and fibrosis [23,30,[166][167][168].…”

FcεRI Signaling of Mast Cells Activates Intracellular Production of Hydrogen Peroxide: Role in the Regulation of Calcium Signals

“…However, there are conflicting data regarding whether rat peritoneal mast cells actually can produce ROS. Swindle et al (24) claimed that the production of ROS observed in rat peritoneal mast cells is attributed to contaminating macrophages rather than to mast cells by themselves.…”