Rutin Ameliorates BHBA-Induced Inflammation and Lipid Accumulation in Calf Hepatocytes Through NF-κB Signaling Pathway.

When subclinical ketosis (SCK) occurs in dairy cows, it leads to an excessive production of β-hydroxybutyrat (BHBA), which disrupts liver lipid metabolism and triggers a series of inflammatory responses. Rutin (RT), a flavonoid extracted from plants, exhibits diverse biological activities. However, its potential to mitigate BHBA-induced liver inflammation and lipid accumulation in dairy cows remains unexplored. In this study, we investigated the effect of RT on the BHBA-induced injury of hepatocytes and the possible mechanism. First, hepatocytes were treated with BHBA (0, 0.3, 0.6, 1.2, 2.4 mM) to assess its effects on inflammation impairment and lipid accumulation. Second, hepatocytes were pretreated with RT (0, 25, 50, 100, 150 μg/mL) to evaluate its protective effects. Third, hepatocytes were divided into five treatment groups: blank control, BHBA treatment, RT + BHBA treatment, NF-κB activator (PDTC) + BHBA treatment, and RT + PDTC + BHBA treatment. This experiment further explored the underlying mechanism of RT in mitigating BHBA-induced hepatocyte injury. The results demonstrated that RT at 100 and 150 μg/mL mitigated the increases in hepatocyte interleukin-1 beta (IL-1β), IL-6, triglyceride (TG), and total cholesterol (TC) contents induced by high concentrations of BHBA (p < 0.05). Compared to the BHBA treatment, 100 μg/mL RT significantly downregulated the relative protein expression of P-NF-κB p65 and the relative mRNA expression of NF-κB p65, tumor necrosis factor-alpha (TNF-α), IL-1β, IL-6, peroxisome proliferator-activated receptor gamma (PPARγ), and microsomal triglyceride transfer protein (MTP), while upregulating the relative mRNA expression of IKBα (p < 0.05). Additionally, these effects were more pronounced with the combined pretreatment of the PDTC and RT. In conclusion, RT inhibits BHBA-triggered hepatocyte inflammation and lipid accumulation by modulating the NF-κB signaling pathway, implying that RT may be a promising target for ameliorating damage in SCK cows.