Astragaloside Ⅳ inhibits inflammation after cerebral ischemia in rats through promoting microglia/macrophage M2 polarization / 浙江大学学报·医学版

OBJECTIVE@#To investigate the effects of astragaloside Ⅳ (AS-Ⅳ) on microglia/macrophage M1/M2 polarization and inflammatory response after cerebral ischemia in rats.@*METHODS@#Forty eight male SD rats were randomly divided into sham operation control group, model control group and AS-Ⅳ group with 16 rats in each. Focal cerebral ischemia model was induced by occlusion of the right middle cerebral artery (MCAO) using the intraluminal filament. After ischemia induced, the rats in AS-Ⅳ group were intraperitoneally injected with 40 mg/kg AS-Ⅳ once a day for 3 days. The neurological functions were evaluated by the modified neurological severity score (mNSS) and the corner test on d1 and d3 after modelling. The infarct volume was measured by 2, 3, 5-triphenyl tetrazolium chloride (TTC) staining on d3 after ischemia. The expression of M1 microglia/macrophage markers CD86, inducible nitric oxide synthase (iNOS) and pro-inflammatory factors TNF-α, IL-1β, IL-6, M2 microglia/macrophages markers CD206, arginase-1 (Arg-1), chitinase-like protein (YM1/2) and anti-inflammatory factors interleukin-10 (IL-10) and transforming growth factor beta (TGF-β) was detected by real-time RT-PCR. The expression of CD16/32/Iba1 and CD206/Iba1 was determined by double labeling immunefluorescence method in the peripheral area of cerebral ischemia.@*RESULTS@#Compared with model control group, AS-Ⅳ treatment improved neurological function recovery and reduced infarct volume after ischemia (@*CONCLUSIONS@#The findings suggest that AS-Ⅳ ameliorates brain injury after cerebral ischemia in rats, which may be related to inhibiting inflammation through promoting the polarization of the microglia/macrophage from M1 to M2 phenotype in the ischemic brain.

Acetyl salicylic acid inhibits Th17 airway inflammation via blockade of IL-6 and IL-17 positive feedback

T-helper (Th)17 cell responses are important for the development of neutrophilic inflammatory disease. Recently, we found that acetyl salicylic acid (ASA) inhibited Th17 airway inflammation in an asthma mouse model induced by sensitization with lipopolysaccharide (LPS)-containing allergens. To investigate the mechanism(s) of the inhibitory effect of ASA on the development of Th17 airway inflammation, a neutrophilic asthma mouse model was generated by intranasal sensitization with LPS plus ovalbumin (OVA) and then challenged with OVA alone. Immunologic parameters and airway inflammation were evaluated 6 and 48 h after the last OVA challenge. ASA inhibited the production of interleukin (IL)-17 from lung T cells as well as in vitro Th17 polarization induced by IL-6. Additionally, ASA, but not salicylic acid, suppressed Th17 airway inflammation, which was associated with decreased expression of acetyl-STAT3 (downstream signaling of IL-6) in the lung. Moreover, the production of IL-6 from inflammatory cells, induced by IL-17, was abolished by treatment with ASA, whereas that induced by LPS was not. Altogether, ASA, likely via its acetyl moiety, inhibits Th17 airway inflammation by blockade of IL-6 and IL-17 positive feedback.

Different uptake of gentamicin through TRPV1 and TRPV4 channels determines cochlear hair cell vulnerability

Hair cells at the base of the cochlea appear to be more susceptible to damage by the aminoglycoside gentamicin than those at the apex. However, the mechanism of base-to-apex gradient ototoxicity by gentamicin remains to be elucidated. We report here that gentamicin caused rodent cochlear hair cell damages in a time- and dose-dependent manner. Hair cells at the basal turn were more vulnerable to gentamicin than those at the apical turn. Gentamicin-conjugated Texas Red (GTTR) uptake was predominant in basal turn hair cells in neonatal rats. Transient receptor potential vanilloid 1 (TRPV1) and 4 (TRPV4) expression was confirmed in the cuticular plate, stereocilia and hair cell body of inner hair cells and outer hair cells. The involvement of TRPV1 and TRPV4 in gentamicin trafficking of hair cells was confirmed by exogenous calcium treatment and TRPV inhibitors, including gadolinium and ruthenium red, which resulted in markedly inhibited GTTR uptake and gentamicin-induced hair cell damage in rodent and zebrafish ototoxic model systems. These results indicate that the cytotoxic vulnerability of cochlear hair cells in the basal turn to gentamicin may depend on effective uptake of the drug, which was, in part, mediated by the TRPV1 and TRPV4 proteins.

Regulacion de la presion arterial a traves de canales de potasio / Blood pressure regulation by potassium channels

Los canales de potasio son estructuras proteicas que permiten la difusión de este ion a través de la membrana plasmática. Participan en la génesis del potencial de reposo y a través del mismo regulan el nivel de calcio intracelular y el estado de contracción del músculo liso vascular. Hay dos grandes familias de canales de potasio descriptas en el músculo liso vascular: canales regulados por voltaje y canales regulados por ATP. Las drogas que abren los canales regulados por ATP, minoxidilo y diazóxido, hiperpolarizan la membrana plasmática y son potentes vasodilatadores. En poco tiempo habrá nuevas drogas antihipertensivas que actúen por este mecanismo. Se ha sugerido que la vasodilatación hipóxica y del shock se debe a activación excesiva de estos canales. Se ha propuesto empíricamente que mutaciones en estos canales pueden producir hipertensión arterial.

Morphogenesis of the epithelial cell transporting phenotype: systhesis and distribution of ion channels

The exchange of substance between higher organisms and the environment takes place across epithelia consisting of one or more cell layers. To perform this function, epithelial cells have two basic differentiated properties: 1) they form tight junctions (Tjs) that seal the extracellular space, and 2) they are polarized into an apical and a basolateral domain, with entirely different structural, biochemical and physiological properties. Our understanding of the mechanisms involved in the expression of these properties has been greatly enchanced by the availability of epithelial cell lines that form Tjs and polarize in vitro under conditions suitable for experimental control. In this article we summarize our studies on the synthesis and polarized expression of ion channels in epithelial cells. MDCK cells have four types of K+ channels in the apical domain, and a fifth one in the basolateral domain. The basolateral side also has a population of Cl- channels. Each type of channel is absolutely polarized. Harvesting with trypsin-EDTA reduces the area of the plasma membrane by 50 per cent and the channel population by 90 per cent. Upon plating, these channels are recovered within a few hours. We describe here the main extracellular and intracellular mechanisms involved in these phenomena.