Danggui Buxuetang Alleviates Oxidative Stress and Inflammation in Diabetic Kidney Disease Rats by Improving Mitochondrial Dysfunction of Podocytes / 中国实验方剂学杂志

ABSTRACT

ObjectiveTo investigate the intervention effect of Danggui Buxuetang on oxidative stress and inflammatory response in diabetic kidney disease （DKD） rats from its improvement of podocyte mitochondrial dysfunction. MethodSD rats were randomly divided into the control group and modeling group， and the ones in the latter group rats were fed a high-glucose and high-fat diet and then intraperitoneally injected with a small dose of streptozotocin （STZ） for inducing type 2 diabetes. The successfully modeled rats were randomized into the model group， high- and low-dose （1.44 and 0.72 g·kg-1） Danggui Buxuetang groups， and irbesartan （0.017 g·kg-1）group and gavaged with the corresponding drugs， while those in the normal and model groups with an equal volume of normal saline. After 20 weeks of drug intervention， the urinary microalbumin-to-urine creatinine ratio （UACR） and serum malondialdehyde （MDA） content and manganese superoxide dismutase （MnSOD） activity in each group were measured. The pathological changes in renal tissue were observed by Masson trichrome staining， and periodic acid-silver metheramine （PASM） staining， followed by the observation of ultrastructural changes in podocytes under the transmission electron microscope （TEM）. The expression level of reactive oxygen species （ROS） in rat kidney tissue was detected using a fluorescent probe dihydroethidium （DHE）. The protein expression levels of peroxisome proliferator-activated receptor γ -coactivator -1α （PGC-1α）， nucleotide-binding domain like receptor protein 3 （NLRP3）， and Wilms tumor protein-1 （WT-1） were measured by immunohistochemistry （IHC）， and the expression levels of NLRP3， interleukin-1β （IL-1β），and WT-1 in podocytes by immunofluorescence （IF） assay. The mRNA expression levels of PGC-1α and NLRP3 in the renal tissues were determined by real-time fluorescence quantitative polymerase chain reaction （Real-time PCR）， and the protein expression levels of PGC-1α， MnSOD， NLRP3， and IL-1β were assayed by Western blot. ResultCompared with the normal group， the model group exhibited elevated UACR and MDA content， weakened MnSOD activity （P<0.01）， glomerular hypertrophy， thickened basement membrane， mesangial hyperplasia， increased extracellular matrix， K-W nodules， podocyte mitochondrial swelling， disordered mitochondrial cristae， foot process fusion or loss， vacuolization， increased ROS （P<0.01）， enhanced NLRP3 and IL-1β but diminished WT-1 expression in podocytes， down-regulated PGC-1α mRNA expression （P<0.01） and PGC-1α and MnSOD protein expression （P<0.01）， and up-regulated NLRP3 mRNA expression and NLRP3 and IL-1β protein expression （P<0.01）. Compared with the model group， Danggui Buxuetang high-dose group significantly decreased UACR and MDA， enhanced MnSOD activity （P<0.05， P<0.01）， improved renal histopathology and podocyte mitochondrial ultrastructure， decreased ROS （P<0.05， P<0.01） and NLRP3 and IL-1β expression in podocytes， enhanced WT-1 expression in podocytes， up-regulated the mRNA and protein levels of PGC-1α and MnSOD， and down-regulated the mRNA and protein levels of NLRP3 and IL-1β （P<0.05， P<0.01）. ConclusionDanggui Buxuetang alleviates oxidative stress， reduces inflammatory response， protects kidney， and delays the progression of DKD possibly by improving the mitochondrial dysfunction in podocytes of DKD rats.