Danggui Buxuetang Inhibits Mitochondrial Fission and Apoptosis of Podocytes in Rat of Diabetic Kidney Disease via AKAP1/Drp1 Signaling Pathway / 中国实验方剂学杂志

ABSTRACT

ObjectiveTo observe the effects of Danggui Buxuetang on the mitochondrial fission and apoptosis of podocytes in the rat model of diabetic kidney disease （DKD） and to explore the protective effect and mechanism of Danggui Buxuetang on DKD rats. MethodSD rats were randomized into a modeling group （n=65， fed with a high-sugar and high-fat diet） and a normal group （n=10， fed with a normal diet）. After 6 weeks， the modeled rats were injected intraperitoneally with streptozotocin （STZ） for the modeling of type 2 diabetes mellitus （T2DM）. Sixty T2DM rats were randomized into model， irbesartan （0.014 g·kg-1）， and low-， medium-， and high-dose （0.36， 0.72， 1.44 g·kg-1， respectively） Danggui Buxuetang groups and administrated with corresponding drugs by gavage for 16 weeks. The levels of fasting blood glucose （FBG） and 24 h urinary protein （24 h UTP） were determined at the end of the 16th week. The pathological changes of the renal tissue were observed by hematoxylin-eosin and Masson staining. The mitochondrial ultrastructure of rat podocytes was observed by transmission electron microscopy. The level of reactive oxygen species （ROS） in the renal tissue of rats was measured by the fluorescent probe labeling of dihydroethidium （DHE）. The apoptosis of renal cells was detected by terminal-deoxynucleotidyl transferase-mediated dUTP nick end labeling （TUNEL）. The expression levels of Synaptopodin， Podocin， and cleaved caspase-3 in renal podocytes were detected by the immunohistochemical method （IHC）. Western blot was employed to determine the protein levels of A-kinase anchoring protein 1 （AKAP1）， phosphorylated dynamin-related protein 1 （p-Drp1）， mitofusin-2 （Mfn2）， B-cell lymphoma-2 （Bcl-2）， and Bcl-2-associated X protein （Bax）. ResultCompared with the control group， the model group showed elevated levels of FBG and 24 h UTP， mesangial hyperplasia， basement membrane thickening， mitochondrial swelling， mitochondrial crista breakage and disorder， and increased ROS and TUNEL-positive cells. In addition， the model group showcased down-regulated expression of Synaptopodin and Podocin， increased expression of cleaved Caspase-3， up-regulated protein levels of AKAP1 and p-Drp1 ， and down-regulated protein levels of Mfn2 and Bcl-2/Bax （P<0.01）. Compared with the model group， high-dose Danggui Buxuetang lowered the levels of FBG and 24 h UTP， alleviated the pathological injuries of the renal tissue and the mitochondrial injury of podocytes， decreased ROS and TUNEL-positive cells， promoted the expression of Synaptopodin and Podocin， inhibited the expression of cleaved Caspase-3， down-regulated the protein levels of AKAP1 and p-Drp1， and up-regulated the protein levels of Mfn2 and Bcl-2/Bax （P<0.05， P<0.01）. ConclusionDanggui Buxuetang may inhibit mitochondrial fission and apoptosis of podocytes and reduce urine protein by regulating the AKAP1/Drp1 pathway， thereby delaying the progression of DKD.