CASC3 and Miyoshi myopathy: From the results of in vitro cytotoxicity experiments, it can be seen that BTZ@PLGA/EM has little toxicity to normal MC3T3 cells (Figure 3e), moreover, high concentrations of BTZ showed no significant toxicity to MC3T3 cells, while it has obvious cytotoxicity to MM cells, with the increase of concentration, the killing effect on MM cells was enhanced (Figure 3f).