Attenuation mechanism of gamboges during processing based on inflammatory toxicity and AQP3, AQP4 protein and mRNA expressions in rat gastric and duodenal tissues / 中国中药杂志

ABSTRACT

To expand the clinical application of gamboges, it is necessary to study crude gamboges' toxicity after oral administration and attenuation mechanism during processing. In this study, crude gamboges' toxicity was judged by multiple assays, including inflammatory mediums [such as nitric oxide (NO), tumor necrosis factor alpha (TNF-α), and interleukin 6 (IL-6)] released by macrophage RAW264.7, and pathological manifestations of rat stomach and duodenal tissues after oral administration with crude and processed gamboges. The attenuation mechanism during processing was studied by detecting AQP3, AQP4 protein and mRNA expression in rat gastric and duodenal tissues using immunohistochemical assay and real-time fluorescent quantitative PCR technique. According to the results, crude gamboges group showed promotion in release of NO, TNF-α and IL-6 by macrophage RAW264.7 in a dose-dependent manner; Compared with crude gamboges group, processed gamboges group showed reduction in release of NO and IL-6, with increase in TNF-α. Crude gamboges could cause rat diarrhea, white blood cells increase, lymphocytes decrease, hyperemia and edema in rat gastric mucosa, duodenal mucosal necrosis and inflammatory cells infiltration. All of these results proved that gamboges had the inflammatory toxicity in gastric and duodenal tissues after oral administration in a dose-dependent manner, which however reduced after processing. In addition to the inflammatory toxicity, the mRNA and protein expressions of aquaporin 3 (AQP3), aquaporin 4 (AQP4) in gastric and duodenal tissues of high-dose crude gamboges group were increased significantly (P<0.05), while the protein and mRNA expressions of AQP3, AQP4 were weakened in processed gamboges group. The results showed that AQP3, AQP4 protein and mRNA expressions were positively correlated with the inflammatory toxicity. In conclusion, down-regulation of AQP3, AQP4 protein and mRNA expressions may be one of attenuation mechanisms in processing gamboges.