To investigate the protective effect and mechanism of human amnion epithelial stem cells (hAECs) against liver ischemia-reperfusion injury (IRI) in mice.

Ten C57BL/6 mice were randomly divided into the control group (IRI+ PBS group) and the experimental group (IRI+ hAECs group), with 5 mice in each group. The IRI+ PBS group was injected with PBS (100 μL) via the dorsal vein of the penis, and the IRI+ hAECs group was injected with hAECs (1×10⁵ pieces) via the dorsal vein of the penis. At 0.5 h after injection, ischemia at normal temperature for 1.5 h and reperfusion for 6 h. HE staining was used to observe the pathological changes of mouse liver tissue. Biochemical analysis was used to measure serum ALT, AST and lactate dehydrogenase (LDH) levels. Immunohistochemical staining was used to observe the infiltration of macrophages (F4/80) and M1 (CD68) and M2 (CD206) macrophages. At the same time, the apoptosis-related factors B-lymphoma-2 (BCL-2), BCL-2-related X protein (BAX), cysteinyl aspartate-specific protease (Caspase)-3 and Caspase-7, and the inflammatory factors IL-6, IL-23, TNF-α and IL-β mRNA relative expressions were also compared. Data of continuous variables conforming to normal distribution were compared by independent sample t test. P<0.05 was considered statistically significant.

Compared with the IRI + PBS group, the pathological damage of the liver tissue was significantly improved in the IRI + hAECs group. The expression levels of serum ALT, AST and LDH in the IRI+ hAECs group were (1 456±20), (1 375±49) and (2 435±147) U/L, respectively, and those in the IRI+ PBS group were (3 919±48), (3 142±145) and (3 499±147) U/L, the differences were statistically significant (t=47.13, 11.53 and 4.53, all P<0.05). The mRNA expression levels of BCL-2, BAX, Caspase-3 and Caspase-7 in the IRI + hAECs group were (0.20±0.05), (0.19±0.09), (0.46±0.13) and (0.27±0.03), respectively; they were all lower than those in the IRI + PBS group (1.01±0.16), (1.02±0.28), (1.01±0.17) and (1.00±0.11), and the differences were statistically significant (t=8.45, 4.88, 4.39 and 10.79, all P<0.05). Immunohistochemical staining showed that macrophage infiltration was lower in the IRI+ hAECs group. The mRNA levels of IL-6, IL-23, TNF-α and IL-β in the IRI+ hAECs group were (0.38±0.04), (0.33±0.05), (0.43±0.08) and (0.12±0.04), respectively; they were all lower than those in the IRI+ PBS group (1.10±0.11), (1.00±0.05), (1.00±0.02) and (1.10±0.06), and the differences were statistically significant (t=11.27, 16.37, 12.96 and 22.34, all P<0.05). The expression of M1 macrophages cells was significantly decreased in the IRI+ hAECs group, and the proportion of M2 macrophages cells was increased.

hAECs protect mice from liver IRI by attenuating inflammatory responses by modulating the polarization of M1/M2 macrophages.