[Effects of Thapsigargin on Intracellular Ca²⁺ and Caspase-3 Protein Expression in Mouse Lung Fibroblast]

To explore the effects of calcium pump inhibitor thapsigargin (TG) on intracellular Ca²⁺ and the expression of caspase-3 protein in mouse lung fibroblast.

Mice lung fibroblast cells were divided into three groups: the blank control group,transforming growth factor-β₁ (TGF-β₁) group and TG treated group. The cells were induced by 5 ng/mL TGF-β₁ for 24 h in TGF-β₁ group and TG group,4 μmol/L TG was added in TG group for 24 h. After 48 h,the cells were collected,and the cell structure was observed by transmission electron microscope,intracellular Ca²⁺ level was detected with laser confocal microscope,the protein expression of caspase-3 was examined using immunohistochemistry method.

Transmission electron microscopy showed that the cells in the blank control group had obvious nucleolus,complete organelles and less apoptosis. In TGF-β₁ group,the cell morphology was intact,chromatin was evenly distributed,and no apoptotic cells were found. In TG group,there were a large number of apoptosis of fibroblasts,chromatin clumps in nuclei and a small amount of collagen fibers. The level of Ca²⁺ in TGF-β₁ group was significantly lower than that in control group (P<0.05),and which in TG group was significantly higher (P<0.05 ). The protein expression of caspase-3 in TGF-β₁ group were significantly lower than that in blank control group (P<0.05),which in TG group increased obviously (P<0.05).

TG could cause intracellular calcium dysregulation in mouse lung fibroblasts,increase caspase-3 protein expression and promote cell apoptosis.