Bletilla striata polysaccharides alleviate metabolic dysfunction-associated steatotic liver disease through enhancing hepatocyte RelA/ HNF1α signaling

Figure 8 Treatment with conditional rat Bletilla striata polysaccharides-containing serum enhances the sodium oleate/sodium palmitate-stimulated nuclear factor kappa B p65/hepatocyte nuclear factor-1 alpha signaling and alleviates lipid metabolism disorder in hepatocytes. A: Healthy rats were treated with control phosphate buffer saline or 0.2 g/kg Bletilla striata polysaccharides (BSP) by gavage every 12 hours for three consecutive days. Two hours after the last administration, their blood samples were obtained for preparing conditional rat serum samples. AML-12 and HepG2 cells were cultured in the medium supplemented with 10% control or conditional rat BSP-containing serum and stimulated with 250/125 μmol/L sodium oleate/sodium palmitate for 48 hours; B: Oil red O staining of lipids in AML-12 and HepG2 cells; C: Intracellular triglycerides content; D: Cell counting kit-8 assay of the viability; E: Intracellular malondialdehyde levels; F: Reduced glutathione levels; G: Western blot analysis of the relative levels of nuclear factor kappa B p65, and hepatocyte nuclear factor-1 alpha expression; H: Western blot analysis of the relative levels of endoplasmic reticulum stress-related protein expression; I: Western blot analysis of the relative levels of lipid metabolism-related protein expression; J: Western blot analysis of the relative levels of cleaved caspase-3, and mixed lineage kinase domain-like protein phosphorylation; K: Flow cytometry analysis of the frequency of apoptotic cells. Data are representative images or expressed as the mean ± SD of each group from three separate experiments. ^bP < 0.01. ¹P < 0.01 vs the sodium oleate/sodium palmitate group. SO/SP: Sodium oleate/sodium palmitate; BSP: Bletilla striata polysaccharides; TG: Triglycerides; MDA: Malondialdehyde; GSH: Glutathione; HNF1α: Hepatocyte nuclear factor-1 alpha; GRP78: 78-kDa glucose-regulated protein; CHOP: CCAAT-enhancer-binding protein homologous protein; HRD1: 3-hydroxy-3-methyl glutaryl coenzyme A reductase degradation 1 homolog; SREBP1c: Cleaved sterol regulatory element-binding protein 1; MTP: Microsomal triglyceride transfer protein; MCAD: Medium-chain acyl-CoA dehydrogenase; GPX4: Glutathione peroxidase 4; MLKL: Mixed lineage kinase domain-like protein; OD: Optical density; ATF4: Activating transcription factor 4; RelA: Nuclear factor kappa B p65.