IHC staining of Sox2, Klf4, and Sox9 demonstrated that the number of Sox2+, Klf4+, and Sox9+ cells was increased in the PVL group of WT mice, but there was no significance in the numbers in TLR4-/- mice, and the positive cells were all located in the PV area (Fig. 5h), suggesting that LPS in the portal vein regulates the expression of pluripotent markers via the TLR4 pathway. Here, SOX9 is linked to periventricular leukomalacia.