Effects Of Astragalus Polysaccharides On Neonatal Rat Ventricular Myocytes Hypertrophy And TLR4Expression Induced By Tumor Necrosis Factor-α

ObjectiveTo characterize the expression of Toll-like receptor4(TLR4) and nuclearfactor-kappa B (NF-B) in neonatal rat cardiomyocytes hypertrophy induced bytumor necrosis factor-α (TNF-α), and further to investigate the influence ofAstragalus polysaccharides (APS) on TNF-α-induced hypertrophy of neonatalrat cardiomyocytes and the relevant mechanism.MethodsCultured neonatal rat ventricular myocytes were stimulated with100μg·L-1tumor necrosis factor-α (TNF-α) to induce myocardial hypertrophy. Culturedneonatal rat cardiomyocytes were divided into7groups:1)normal,2) TNF-α,3)NF-B inhibitor BAY11-7082,4) TNF-α+BAY11-7082,5) TNF-α+APS (25mg·L-1),6)TNF-α+APS (50mg·L-1),7) TNF-α+APS (100mg·L-1), after addingdifferent treatments for48h to measure different indicators. Total proteincontent was assayed by coomassie brilliant blue method; the size ofcardiomyocytes was measured by computer photograph analysis system; actinfilaments were visualized using rhodamine-labeled phalloidin; the expressionof ANP and TLR4mRNA were determined by RT-PCR; TLR4、p65and IκBαprotein expression were assessed by Western blot; IL-1β protein expression inmedium was measured by ELISA. ResultsCompared with Normal group, cardiomyocytes cultured in TNF-α showedan significantly hypertrophic responses, including the reorganization of actinfilaments, protein content (P<0.01), cell size (P<0.01), ANP mRNA (P<0.01),as well as a higher expression of p65protein (P<0.01), TLR4protein andmRNA (P<0.01), IL-1β protein (P<0.01) and lower expression of IκBα protein(P<0.01).Cardiomyocytes cultured in APS were remarkably attenuated compared toTNF-α group. APS showed the function on reducing protein content(P<0.05orP<0.01), cell size(P<0.05or P<0.01), ANP mRNA(P<0.05or P<0.01), thereorganization of actin filaments, the expression of p65protein(P<0.05orP<0.01), TLR4protein and mRNA(P<0.05or P<0.01), IL-1β protein(P<0.05orP<0.01) and higher expression of IκBα protein(P<0.05or P<0.01).ConclusionAstragalus Polysaccharides ameliorate hypertrophic and inflammatoryresponses of cardiomyocytes induced by TNF-α, which be related to abolishTLR4/NF-B signal transduction pathway.