Alcohol Extract of Angelicae Pubescentis Radix Treats Gouty Arthritis Induced by MSU via NLRP3/ASC/Caspase-1 Signaling Pathway / 中国实验方剂学杂志

ObjectiveTo explore the efficacy and mechanism of the alcohol extract DH50 of Angelicae Pubescentis Radix in treating gouty arthritis induced by monosodium urate （MSU） crystals in vivo and in vitro. MethodFifty male SD rats were randomly assigned into five groups （n=10）： a normal group， a model group， a dexamethasone （DXMS， 0.07 mg·kg-1） group， and low- （DH50-D， 9 mg·kg-1） and high-dose （DH50-G， 18 mg·kg-1） DH50 groups. The rats in the normal group and model group were administrated with the same amount of pure water. On day 5， the gouty arthritis model was established by injecting MSU into the right ankle joint of rats. The toe volume and joint inflammation index were measured 4， 8， 24， and 48 h after modeling. The pathological changes of the synovial tissue were detected by hematoxylin-eosin （HE） staining. Enzyme-linked immunosorbent assay （ELISA） was employed to measure the levels of tumor necrosis factor-alpha （TNF-α）， interleukin （IL）-1β， and IL-6 in the synovial tissue. Western blot was employed to measure the protein levels of NOD-like receptor protein 3 （NLRP3）， cysteine-aspartic protease-1 （Caspase-1）， apoptosis-associated speck-like protein containing a C-terminal caspase recruitment domain （ASC）， IL-1β， and cyclooxygenase-2 （COX-2） in the synovial tissue. Furthermore， the cell inflammation model was established with RAW264.7 cells stimulated with MSU （75 mg·L-1）. The cell experiments were carried out with 6 groups： a normal group， a model group， a positive drug （DXMS， 100 μmol·L-1） group， and low- （DH50-D， 25 mg·L-1）， medium- （DH50-Z， 50 mg·L-1）， and high-dose （DH50-G， 100 mg·L-1） DH50 groups. Methyl thiazolyl tetrazolium （MTT） assay was employed to determine the cell viability， ELISA to determine the content of TNF-α in the supernatant of cell culture， and Western blot to determine the protein levels of NLRP3， cleaved Caspase-1， IL-1β， TNF-α， and COX-2. ResultCompared with the normal group， the rat model group showed increased toe swelling degree and joint inflammatory index （P<0.01）， serious infiltration of the synovium， elevated levels of inflammatory cytokines in the tissue homogenate （P<0.01）， and up-regulated protein levels of NLRP3， Caspase-1， ASC， IL-1β， and COX-2 （P<0.05， P<0.01）. Compared with the rat model group， low- and high-dose DH50 mitigated the toe swelling degree， decreased the joint inflammatory index， alleviated the inflammatory infiltration， lowered the levels of inflammatory cytokines in the tissue homogenate （P<0.01）， and down-regulated the expression of related proteins （P<0.05， P<0.01）. Compared with the normal group， the cell model group showed elevated level of TNF-α in the supernatant （P<0.01） and up-regulated protein levels of NLRP3， cleaved Caspase-1， IL-1β， TNF-α， and COX-2 （P<0.05）. Compared with the model group， low， medium， and high doses of DH50 lowered the level of TNF-α in the supernatant of cell culture in a dose-dependent manner and down-regulated the expression of related proteins （P<0.05， P<0.01）. ConclusionDH50 can mitigate gouty arthritis both in vitro and in vivo by inhibiting the activation of NLRP3 inflammasomes and the production of inflammatory cytokines.

Vitamin C alleviates hyperuricemia nephropathy by reducing inflammation and fibrosis.

Hyperuricemia contributes to chronic kidney disease development. However, it has been historically viewed with limited research interest. In this study, we mimicked the development of hyperuricemic nephropathy by using a potassium oxonate-induced hyperuricemia rat model. We found that administering vitamin C at 10 mg/kg/day effectively ameliorated hyperuricemic nephropathy. Compared to the control group, rats with hyperuricemia had significantly increased serum uric acid level, xanthine oxidase activity, and urine microalbumin level, by 5-fold, 1.5-fold, and 4-fold, respectively. At the same time, vitamin C supplementation reverted these values by 20% for serum uric acid level and xanthine oxidase activity and 50% for microalbumin level. Vitamin C also alleviated renal pathology and decreased the expression of pro-inflammatory and pro-fibrotic markers. A further mechanistic study suggested that vitamin C might attenuate hyperuricemic nephropathy in renal tubular epithelial cells induced by monosodium urate (MSU) crystal, at least in part, by directly inhibiting IL-6/JAK2/STAT3 signaling pathway. Meanwhile, in macrophages, vitamin C inhibited the expression of TGF-ß, and reduced ROS level induced by MSU by about 35%. In short, our results suggest that vitamin C supplementation delay the progression of hyperuricemic nephropathy.

Monosodium urate crystal deposition associated with the progress of radiographic grade at the sacroiliac joint in axial SpA: a dual-energy CT study.

BACKGROUND: Previous studies have revealed that ankylosing spondylitis (AS), as the progenitor of axial spondyloarthritis (AxSpA), has been characterized by the insidiously progressive nature of sacroiliitis and spondylitis. Dual-energy computed tomography (DECT) has recently been used to analyse the deposition of monosodium urate (MSU) crystals with higher sensitivity and specificity. However, it remains unclear whether the existence of the MSU crystal deposition detected by DECT at the sacroiliac joint in patients with AxSpA also is associated with the existing structural damage. Here, we performed this study to show the DECT MSU crystal deposits in AxSpA patients without coexisting gout and to ascertain the relationship between the MSU crystal deposition and the structural joint damage of sacroiliac joints. METHODS: One hundred and eighty-six AxSpA patients without coexisting gout were recruited. The plain radiographs of the sacroiliac joint were obtained, along with the DECT scans at the pelvis and the clinical variables. All statistics based on the left or right sacroiliac joint damage grading (0-4) were calculated independently. Bivariate analysis and ordinal logistic regression was performed between the clinical features and radiographic grades at the sacroiliac joint. RESULTS: At the pelvis, large quantities of MSU crystal deposition were found in patients with AxSpA. The average MSU crystal volume at the left sacroiliac joint, the right sacroiliac joint, and the pelvis were 0.902 ± 1.345, 1.074 ± 1.878, and 5.272 ± 9.044 cm3, values which were correlated with serum uric acid concentrations (r = 0.727, 0.740, 0.896; p < 0.001). In bivariate analysis, wide clinical variables were associated with the changes in sacroiliac joint damage. Further, the AxSpA duration, BASFI score, and the volume of MSU crystal at both sides of sacroiliac joint were associated with the progress of radiographic grade at the sacroiliac joints in the ordinal logistic models (left AOR = 1.180, 3.800, 1.920; right AOR = 1.190, 3.034, 1.418; p < 0.01). CONCLUSIONS: Large quantities of MSU crystal deposition detected by DECT were found at the pelvis in AxSpA patients without coexisting gout. In addition to AxSpA duration and BASFI score, the MSU crystal deposition at the sacroiliac joint is associated with the progress of radiographic grade at sacroiliac joints in those patients.