Pyropheophorbide-Α Methyl Ester-mediated Photodynamic Therapy Induces Apoptosis And Inhibits Lps-induced Inflammation In Raw264.7 Macrophages

Aim: This study aimed to determine the effect of pyropheophorbide-α methyl ester(MPPa)-mediated photodynamic therapy(MPPa-PDT)on the apoptosis and inflammation of murine macrophage RAW264.7 cells.Methods: Uptake and subcellular localization of MPPa was detected by flow cytometry and confocal fluorescence microscope.Cell viability was assessed by CCK-8;ROS levels were assessed by DCFH-DA.Cell apoptosis was measured by flow cytometry and Hoechst 33342 staining,whereas mitochondrial membrane potential was detected by JC-1 staining.Secretion of tumor necrosis factor α(TNF-α),interleukin-1β(IL-1β),and interleukin-6(IL-6)was determined using ELISA kits.Caspase-3,cleaved caspase-3,procaspase-9,cleaved caspase-9,PARP,cleaved PARP,Bcl-2,Bax,NF-κB p-p65,pIKKα/β,and p-IκBα were measured by western blotting.Nuclear factor κB(NF-κB)-p65 nuclear translocation was observed by immunofluorescence.Results: MPPa-PDT influenced cell viability in a light dose-dependent manner.It induced ROS formation and RAW264.7 cell apoptosis.It also increased the expression of cleaved caspase-3,cleaved caspase-9,cleaved PARP and Bax,decreased the expression of Bcl-2.While TNF-α,IL-1β,and IL-6 increased in LPS group(model of inflammation),it deceased in LPS-MPPa-PDT group.NF-κB p-p65,p-IKKα/β,and p-IκBα had higher expression in LPS group while that reduced in LPS-MPPa-PDT group.Simultaneously,MPPa-PDT inhibited nuclear translocation of NF-κB-p65 caused by LPS.Conclusions: MPPa-PDT can induce apoptosis and attenuate inflammation in mouse RAW264.7 macrophages,thereby suggesting a promising therapy for atherosclerosis.