Realgar is active ingredient of Angong Niuhuang pill in protection against LPS-induced neuroinflammation

Abstract

To determine the effects of Angong Niuhuang pill (AGNHW) on lipopolysaccharide (LPS)-induced neuroinflammation and further to investigate the role of realgar and cinnabar on AGNHW-mediated neuroprotection. Primary rat midbrain neuron-glia cultures were used as an in vitro model to examine the effects of AGNHW on LPS-induced dopamine (DA) neuronal damage. Cultures were divided randomly into five groups: control, LPS, LPS plus AGNHW, LPS plus realgar and LPS plus cinnabar. Dopaminergic neurotoxicity was measured by [3H] DA uptake assay. The production of intracellular reactive oxygen species (ROS) was quantified via the DCFH-DA probe. Real-time RT-PCR was applied to detect the mRNA expression of pro-inflammatory factors. Then the protein levels of these factors were determined by ELISA and western blot assay. Compared with the control group, LPS apparently decreased DA uptake capacity (P < 0.05); induced the production of intracellular ROS (P < 0.05); enhanced the mRNA expression of TNF-alpha, iNOS, IL-13 and COX-2 (P < 0.05) and the release of TNF-alpha, IL-1beta and PGE2 in the supernatant of cultures (P < 0.05); and also increased the level of iNOS protein (P < 0.05). Compared with the LPS group, AGNHW and realgar significantly inhibited LPS-induced reduction of DA uptake (P < 0.05); attenuated the production of intracellular ROS (P < 0.05) and the mRNA expression of TNF-alpha, iNOS, IL-1beta and COX-2 (P < 0.05) and the release of TNF-alpha, IL-1beta and PGE2 (P < 0.05) and the level of iNOS protein (P < 0.05). However, there was no significant difference between LPS group and LPS plus cinnabar group. AGNHW is effective in protecting against LPS-induced neuroinflammation, and realgar is one of active components for AGNHW to produce anti-inflammatory effects.