Saikosaponin-D attenuates heat stress-induced oxidative damage in LLC-PK1 cells by increasing the expression of anti-oxidant enzymes and HSP72.

Heat stress stimulates the production of reactive oxygen species (ROS), which cause oxidative damage in the kidney. This study clarifies the mechanism by which saikosaponin-d (SSd), which is extracted from the roots of Bupleurum falcatum L, protects heat-stressed pig kidney proximal tubular (LLC-PK1) cells against oxidative damage. SSd alone is not cytotoxic at concentrations of 1 or 3 μg/mL as demonstrated by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. To assess the effects of SSd on heat stress-induced cellular damage, LLC-PK1 cells were pretreated with various concentrations of SSd, heat stressed at 42°C for 1 h, and then returned to 37°C for 9 h. DNA ladder and MTT assays demonstrated that SSd helped to prevent heat stress-induced cellular damage when compared to untreated cells. Additionally, pretreatment with SSd increased the activity of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) but decreased the concentration of malondialdehyde (MD...