[TLR4/NF-kappaB p65 signaling pathway mediates protective effect of triptolide on endothelium in rats with endotoxemia].

The aim of this paper was to observe the effect of triptolide( TP) on cardiovascular function and its possible mechanism by intraperitoneal injection of bacterial lipopolysaccharide in rats with endotoxemia. Sixty male Sprague-Dawley rats were randomly divided intonormal group( NC group),endotoxemia model group( LPS group),TP low concentration intervention group( LPS + TP-L group,25 µg·kg~(-1)),TP middle concentration intervention group( LPS+TP-M group,50 µg·kg~(-1)),TP high concentration intervention group( LPS+TP-H group,100 µg·kg~(-1)) and polymyxin B group( LPS+PMX-B group,0. 2 mg·kg~(-1)). 10 mg·kg~(-1) LPS was injected intraperitoneally for 6 h to replicate the endotoxemia rat model. The rats in TP intervention groups were pre-treated 15 min before intraperitoneal injection of LPS. Rats in each group underwent total arterial intubation to measure hemodynamic parameters: heart rate( HR),left ventricular diastolic pressure( LVDP),the maximum rate of the increase/decrease of left ventricular pressure( ±dp/dtmax). The levels of BNP,CK-MB and c Tn-Ⅰ in serum and levels of TNF-α and IL-6 in plasma were detected by ELISA. The contents of p65 protein in myocardium and contents of p65,TLR4,i NOS and e NOS protein in thoracic aorta were detected by Western blot. As compared with NC group,the hemodynamic indexes in LPS group were significantly decreased; the contents of BNP,CK-MB and c Tn-Ⅰ in serum,TNF-α and IL-6 in plasma,p65 in myocardium,i NOS,e NOS,TLR4 and p65 in vascular tissues were significantly increased. As compared with LPS group,the hemodynamic indexes were significantly improved in LPS+TP-M group,LPS+TP-H group and LPS+PMX-B group; the contents of BNP,CK-MB and c Tn-Ⅰ in serum,TNF-α and IL-6 in plasma,p65 in myocardium,i NOS,e NOS,TLR4 and p65 in vascular tissues were significantly decreased in each treatment group. Triptolide has a protective effect on cardiovascular damage in a dose-dependent manner in endotoxemia rats,probably through TLR4/NF-κB p65 signaling pathway to improve endothelial function.

Characteristics and time points to inhibit ferroptosis in human osteoarthritis.

Ferroptosis is a form of cell death that is triggered by iron-dependent lipid peroxidation and is closely associated with osteoarthritis. The primary interventions for inhibiting ferroptosis in osteoarthritis are anti-lipid peroxidation and iron chelation. The objective of our study is to investigate the characteristics of ferroptosis in osteoarthritis and identify the optimal time points for inhibiting ferroptosis to alleviate disease progression. Ferroptosis-related alterations and markers of OA were analyzed in paired intact and damaged cartilages from OA patients by immunofluorescence, qRT-PCR, mitochondrial membrane potential and immunohistochemistry. We also compared Ferroptosis-related alterations in cartilage of mild, moderate, and severe OA (according to the modified Mankin score). In addition, we compared the effect of Fer-1 on ferroptosis and the protection of chondrocytes by detecting markers of both ferroptosis and OA by immunofluorescence, CCK8 and qRT-PCR. Ferroptosis-related alterations (GPX4 downregulation, ACSL4 upregulation, MDA, LPO accumulation, Mitochondrial membrane potential decreased) in the damaged area cartilage were more severe than those in the intact area and increased with the progression of OA. Compared with mild OA group, the activity of chondrocytes treated with Fer-1 (a ferroptosis inhibitor) was increased, mitochondrial function was improved, and ferroptosis was reduced (GPX4 upregulation, SLC7A11 upregulation, ACSL4 downregulation,), and promoted the expression of COL2A1 and inhibited the expression of MMP13. However, these changes were not observed in moderate and severe OA chondrocytes. Ferroptosis occurs in a region-specific manner and is exacerbated with the progression of human OA cartilage degeneration. Inhibition of ferroptosis might had a therapeutic effect on chondrocytes with mild OA but had no significant therapeutic effect on chondrocytes with moderate to severe OA.