MKI67 and hydrops fetalis: Co-treatment with antioxidant (such as N-acetylcysteine) at 26°C restored cell viability to levels comparable with 18°C, normalizing HF proliferation (41% Ki-67+ cells), suppressing apoptosis (8% TUNEL+ cells) and restoring HF function (e.g., hair shaft elongation, p < 0.001).