HK2 and polycystic ovary syndrome: Knockdown of miR-155-5p significantly downregulated the expression of HK2, LDHA and PKM2 in the blank + miR-155 inhibitor group compared to the blank group (Fig. 7B, D–F); in contrast, miR-155-5p overexpression upregulated the expression of HK2, LDHA and PKM2 in the blank + miR-155 inhibitor group compared to the PCOS group (Fig. 7C–F).