Baicalin ameliorates deficient decidualization in URSA by regulating mitochondrial fission induced necroptosis

Unexplained recurrent spontaneous abortion (URSA) is a common complication of pregnancy that affects the health of pregnant women. Deficient endometrial decidualization has been associated with URSA. However, the underlying mechanism is poorly understood. This study aims to explore the mechanisms of mitochondrial fission induced necroptosis in deficient decidualization in URSA, and explore the regulation of baicalin on this mechanism. Initially, decidual tissues were collected from patients with URSA and health controls. Subsequently, in vitro induced decidualization model of Telomerase-Immortalized Human Endometrial Stromal Cells (T-hESCs) was constructed. Additionally, murine models of URSA (CBA/J x DBA/2) and normal pregnancy (CBA/J x BALB/c) were established, respectively. The level of decidualization, necroptosis, and mitochondrial fission of decidual tissues from clinical samples were detected. The function of mitochondrial fission on necroptosis during decidualization in T-hESCs was assessed by enhancing or inhibiting mitochondrial fission or necroptosis. Finally, CBA/J x DBA/2 pregnant mice were administrated with different doses of baicalin or saline, and the expression of mitochondrial fission, necroptosis, and decidualization markers were verified. The results of the study demonstrated a significant decrease in decidualization markers in the decidual tissues of URSA patients (P < 0.05), along with an increase in the incidence of cell necroptosis (P < 0.05) and hyperactive mitochondrial fission (P < 0.05). In vitro experiments, LPS was induced to trigger necroptosis of T-hESCs during induced decidualization, and decidualization markers IGFBP1 and PRL were subsequently decreased (P < 0.05). Besides, the mitochondrial fission agonist Tyrphostin A9 was found to promote the level of necroptosis (P < 0.05) and induced deficient decidualization (P < 0.05), which could be rescued by mitochondrial fission inhibitor Mdivi-1 and necroptosis inhibitor Nec-1 (P < 0.05). In addition, baicalin was shown to reduce hyperactive mitochondrial fission (P < 0.05), necroptosis (P < 0.05) and ameliorate deficient decidualization in vitro and in URSA murine models (P < 0.05). Collectively, baicalin shows potential in ameliorating deficient decidualization in URSA by inhibiting mitochondrial fission-triggered necroptosis.