Baicalin Ameliorates Defective Decidualization in URSA by Regulating Mitochondrial Fission Induced Necroptosis

Defective decidualization is a significant pathological feature of URSA. And the potential relationship between mitochondrial fission, necroptosis and defective decidualization remains unknown. Baicalin plays an important role in regulating mitochondrial fission and programmed cell death. However, whether baicalin has a protective effect on defective decidualization in URSA has not been reported thus far. This study aims to explore the mechanisms of mitochondrial fission induced necroptosis in defective decidualization in URSA and the regulation of baicalin. First, decidual tissues were collected from URSA and health controls. And then, T-hESC was treated with lipopolysaccharide (LPS), Tyrphostin A9 (TA9), TA9+necrostatin-1(Nec-1) and TA9+baicalin during in vitro decidualization. Besides, URSA mice were established and randomly administrated with low, medium, and high doses of baicalin as well as saline. Results showed that decidualization markers prolactin (PRL) and insulin-like growth factor-binding protein-1 (IGFBP1) in patients with URSA were significantly decreased (P<0.05). The incidence of cell necroptosis was increased, manifested with increased Annexin V and PI positive cells, high level of pRIP3 T231(P<0.01) and pMLKL S358 (P<0.05). Moreover, mitochondrial fission was also hyperactive, featured by elevated level of Fis1 (P<0.01) and Drp1 (P<0.05). In vitro experiments, LPS was induced to trigger necroptosis of T-hESC during induced decidualization, and IGFBP1 and PRL were subsequently decreased (P<0.05). Besides, mitochondrial fission inducer TA9 promoted the level of necroptosis (P<0.05) and induced defective decidualization, which could be rescued by necroptosis inhibitor Nec-1 (P<0.05). In addition, baicalin could reduce mitochondrial fission (P<0.05), necroptosis (P<0.05) and ameliorate defective decidualization in vivo and in vitro (P<0.05). In conclusion, hyperactive mitochondrial fission could promote necroptosis, thus inducing defective decidualization. And baicalin could ameliorates defective decidualization in URSA by regulating mitochondrial fission induced necroptosis.