(Fig. 6a, f) In the NAC(1–12) group, the expression of p-PERK, ATF4, HSP70, HSP60 and ClpP was significantly increased; however, the NAC(1–6) treatment had no effect compared to the HF group (Fig. 6a, b, c, d, e, f). Here, CLPP is linked to hydrops fetalis.