RESUMO
ObjectiveTo explore the mechanism of Buzhong Yiqitang-containing serum in alleviating the cisplatin resistance in human non-small cell lung cancer （A549/DDP） cells via regulating the nuclear factor E2-related factor 2 （Nrf2）/reactive oxygen species （ROS） signaling pathway. MethodThe serum containing Buzhong Yiqitang was prepared and A549/DDP cells were cultured and randomly grouped： blank （10% blank serum）， cisplatin （10% blank serum+20 mg·L-1 cisplatin）， Buzhong Yiqitang （10% Buzhong Yiqitang-containing serum+20 mg·L-1 cisplatin）， ML385 （10% blank serum+5 μmol·L-1 ML385+20 mg·L-1 cisplatin）， Buzhong Yiqitang+ML385 （10% Buzhong Yiqitang-containing serum+5 μmol·L-1 ML385+20 mg·L-1 cisplatin）， tertiary butylhydroquinone （TBHQ） （10% blank serum+5 μmol·L-1 TBHQ+20 mg·L-1 cisplatin）， and Buzhong Yiqitang+TBHQ （10% Buzhong Yiqitang-containing serum+5 μmol·L-1 TBHQ+20 mg·L-1 cisplatin）. The median inhibitory concentration （IC50） of cisplatin in each group was determined by the cell counting kit-8 （CCK-8） method and the resistance index （RI） was calculated. The apoptosis rate was detected by flow cytometry. The ROS content of each group was determined with the DCFH-DA fluorescence probe. Western blot was employed to determine the protein levels of Nrf2， cleaved cysteinyl aspartate-specific protease-3 （cleaved Caspase-3）， cytochrome C （Cyt C）， and B-cell lymphoma-2 （Bcl-2）. ResultCompared with those in the cisplatin group， the IC50 and RI of A549/DDP cells to cisplatin in Buzhong Yiqitang， ML385， and Buzhong Yiqitang+ML385 groups decreased （P˂0.05）. Compared with the blank group， the cisplatin， Buzhong Yiqitang， ML385， and Buzhong Yiqitang+ML385 groups showed increased apoptosis rate of A549/DDP cells （P˂0.05）. Compared with the blank group， cisplatin promoted the expression of Nrf2 （P˂0.05）. Compared with the cisplatin group， Buzhong Yiqitang， ML385， and Buzhong Yiqitang+ML385 inhibited the expression of Nrf2 （P<0.05）， elevated the ROS level （P˂0.05）， up-regulated the protein levels of cleaved Caspase-3 and Cyt C， and down-regulated the protein level of Bcl-2 （P<0.05）， which were the most significant in the Buzhong Yiqitang+ML385 group. Compared with the cisplatin group， the TBHQ group showed increased IC50 and RI of cisplatin （P<0.05）， decreased apoptosis rate of A549/DDP cells （P<0.05）， up-regulated protein levels of Nrf2 and Bcl-2 （P<0.05）， lowered level of ROS （P˂0.05）， and down-regulated protein levels of cleaved Caspase-3 and Cyt C （P<0.05）. Compared with the TBHQ group， Buzhong Yiqitang+TBHQ decreased the IC50 and RI of cisplatin in A549/DDP cells （P<0.05）， increased the apoptosis rate （P<0.05）， down-regulated the protein levels of Nrf2 and Bcl-2 （P<0.05）， increased ROS （P˂0.05）， and up-regulated the protein levels of cleaved Caspase-3 and Cyt C （P<0.05）. ConclusionBuzhong Yiqitang induced apoptosis by inhibiting Nrf2/ROS pathway to alleviate cisplatin resistance in A549/DDP cells.