Hydrogen Sulfide Attenuates Lipopolysaccharide-Induced Inflammation via the P-glycoprotein and NF-κB Pathway in Astrocytes.

Astrocyte activation is key in neurodegenerative diseases. Hydrogen sulfide (H2S) exhibits neuroprotective effects on astrocytes, although the underlying molecular mechanism remains unclear. Here, we explored the effects of H2S on lipopolysaccharide (LPS)-induced astrocyte activation and astrocyte-mediated neuroinflammation. After inducing primary astrocytes via LPS exposure, H2S levels were altered. The generation and secretion of inflammatory mediators by astrocytes and their interrelation with P-glycoprotein (P-gp), an important transporter belonging to the ABC transporter family, were assessed. Activated astrocytes showed upregulated glial fibrillary acidic protein (GFAP) mRNA expression, and significantly increased proinflammatory factor mRNA/protein expression and release. The secretory capacity of astrocytes was reduced, with significantly decreased proinflammatory factor levels in culture supernatant after P-gp inhibitor verapamil pretreatment. The increase in the intracellular H2S level inhibited LPS-induced GFAP expression and P65 nuclear entry in astrocytes. mRNA expression and release of proinflammatory factors were reduced significantly, with no significant changes in cytoplasmic protein expression. S-sulfhydration levels increased significantly with the increased concentration of sodium hydrosulfide or S-adenosyl-L-methionine addition, with only moderate changes in astrocyte P-gp expression. H2S regulates NF-κB activation, leads to S-sulfhydration of P-gp, and inhibits the biosynthesis and secretion of proinflammatory factors by astrocytes. The regulatory effects of H2S on astrocytes may have clinical value for exploring new therapeutic strategies against neurodegenerative diseases.

[Study on the mechanism of tripterygium wilfordii ployglycosidium in preventing type 1 nonobese diabetic mice].

OBJECTIVE: To observe the immunity preventive action of Tripterygium wilfordii ployglycosidium (TWP) on type 1 diabetes mellitus (T1DM) in non-obese diabetic (NOD)mice and explore its possible mechanism. METHODS: Changes of blood glucose, the incidence rate of T1DM and pancreatitis were observed and the expressions of IFN-gamma,TNF-alpha, IL-10mRNA in pancreas of mice detected by RT-PCR after NOD mice were given TWP by adopting cyclophosphamide accelerated induction of T1DM. RESULTS: The mean blood glucose level in TWP group (10.73 mmol/L) was lower than that in the control group (20. 53 mmol/L) at the end of the experiment(P < 0.01 ). The incidence rate of T1DM in TWP group (43. 33% ) was lower than that in the control group (71.43% , P <0. 01). The mean grade of inflammation of pancreatic islet in TWP group (1.45 +/- 1. 11) was lower than that in the control group (2. 27 +/- 1.22, P <0. 05 ). In TWP group the number of insulin-positive cells was 242. 80 +/-168.93 ,which was more than that of control group with significant difference (95.60 +/- 39.55,P <0.05). The expressions of TNF-alpha mRNA and IFN--gamma mRNA were lower (P <0.01). No obvious change was found in IL-10 mRNA expression. CONCLUSION: TWP could prevent the occurrence of T1DM in NOD mice, whose mechanism might be correlated to the down-regulating of the expression of Thl cytokines in pancreatic tissues.