Influence of Didang Xianxiong Decoction on Apoptosis of Podocytes in Diabetes Rats Through PI3K/Akt Signaling Pathway / 中国实验方剂学杂志

ABSTRACT

ObjectiveTo observe the protective effect of Didang Xianxiong decoction on the kidneys of diabetic rats， its regulation on the phosphatidylinositol 3-kinase （PI3K）/protein kinase B （Akt） signaling pathway， and its influence on podocyte apoptosis and explore the mechanism of Didang Xianxiong decoction in improving diabetic nephropathy. MethodThe diabetic model was established by a single intraperitoneal injection of streptozotocin （STZ） solution of 55 mg·kg-1. The successfully replicated model rats were randomly divided into the model group， Didang Xianxiong decoction group （8.10 g·kg-1）， Xiao Xianxiongtang group （4.05 g·kg-1）， Didangtang group （4.05 g·kg-1）， and alagebrium （ALT-711） group （3 mg·kg-1）， with six rats in each group. In addition， six rats were included in the blank group. After continuous administration for eight weeks， hematoxylin-eosin （HE） staining was used to observe the pathological changes in rats' kidney tissue. Masson staining was used to observe the degree of collagen deposition. Periodic acid-Schiff （PAS） staining was used to observe basement membrane lesions， and immunohistochemistry was used to detect the expression of phosphorylation （p）-PI3K and p-Akt proteins in rats' kidney tissue. The terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling （TUNEL） method was used to detect podocyte apoptosis. Real-time fluorescence quantitative polymerase chain reaction （Real-time PCR） was used to detect the mRNA expression of PI3K and Akt in rats' kidney tissue. Western blot was used to detect the protein expression of PI3K， p-PI3K， Akt， p-Akt， B-cell lymphoma 2 （Bcl-2）， Bcl-2-associated X protein （Bax）， phosphorylation glycogen synthase kinase-3β （p-GSK-3β）， and Caspase-3 in the kidney tissue. ResultCompared with the normal group， the model group had compensatory expansion of glomeruli， proliferation of mesangial cells， a large amount of collagen deposition in the mesangial stroma， thickening of the basement membrane， decreased mRNA expression of PI3K and Akt， and inhibition of PI3K and Akt protein phosphorylation （P<0.01）. It also underwent enhanced apoptotic signaling， decreased expression of anti-apoptotic protein Bcl-2 （P<0.01）， and increased expression of Bax， p-GSK-3β， and Caspase-3 （P<0.01）. Compared with the model group， Didang Xianxiong decoction significantly improved kidney tissue pathology， increased mRNA expression of PI3K and Akt （P<0.01）， significantly up-regulated phosphorylation levels of PI3K and Akt proteins （P<0.01） and Bcl-2 expression （P<0.01）， downregulated the expression of Bax， p-GSK-3β， and Caspase-3 （P<0.01）， and weakened podocyte apoptotic signaling. ConclusionDidang Xianxiong decoction may promote the activation of the PI3K/Akt signaling pathway， inhibit podocyte apoptosis， and thus slow down the progression of diabetic nephropathy.