Abstract: Objective To explore the effect of postnatal infection on SOX10 expression in cerebral white matter in immature rats. Methods A total of 96 newborn SD rats were randomly divided into hypoxia group, lipopolysaccharide (LPS) group, and control group. At day 3 and 6 after birth, the rats in LPS group and hypoxia group were intraperitoneally injected with 0.25 mg/kg of LPS while the rats in control group were injected with normal saline. Meanwhile the rats in hypoxia group were maintained in a hypoxic tank under atmospheric pressure and thermostatic water bath at 37℃ for 2 hours of ventilation with mixed gas containing 8% O2 and 92% N2 at a rate of 2 L/min starting 3 days after birth. At day 7, 10, 14, 21 after birth, eight rats in each groups were sacrificed and the cerebral white matter was extracted. HE staining was performed to observe the pathological changes of cerebral white matter by light microscopy. The expression of SOX10 in cerebral white matter was determined by immunohistochemical and Western blotting analysis. The expression of TLR-4 was determined by Western blotting. Results In LPS group and hypoxia group, the SOX10 positive cells and expressions of SOX 10 and TLR-4 were increased at day 7, reached the peak at day 10, and then gradually declined. There were significant differences between any two time points (P<0.05). In control group, there were a few positive cells and limited expressions of SOX 10 and TLR-4 and there were no differences between any two time points (P>0.05). At each time point, the difference in the SOX10 positive cells and the expressions of SOX 10 and TLR-4 were statistically significant among three groups (P<0.05) in the order of hypoxia group > LPS group > control group and there were significantly differences between each groups (P<0.05). Conclusions Postnatal infections can lead to cerebral white matter lesions in immature rats. The existence of both hypoxia and infection can aggravate the brain injury. The high expression of SOX 10 may have the protective effect.