Mesenchymal stem cells (MSCs) have been reported to promote the regeneration of injured tissue via their paracrine abilities, which are enhanced by hypoxic preconditioning. In this study, we examined the therapeutic efficacy of hypoxia-preconditioned MSCs on renal fibrosis and inflammation in rats with ischemia-reperfusion injury (IRI). MSCs derived from rats and humans were incubated in 1% O2 conditions (1%O2 MSCs) for 24 h. After IRI, 1%O2 MSCs or MSCs cultured under normoxic conditions (21%O2 MSCs) were injected through the abdominal aorta. At 7 or 21 days post-injection, the rats were sacrificed and their kidneys were analyzed. In in vitro experiments, we examined whether 1%O2 MSCs enhanced the ability to produce anti-fibrotic humoral factors using transforming growth factor (TGF)-β1-stimulated HK-2 cells incubated with conditioned medium from MSCs. Administration of rat 1%O2 MSCs (1%O2 rMSCs) attenuated renal fibrosis and inflammation more significantly than rat 21%O2 MSCs. Notably, human 1%O2 MSCs (1%O2 hMSCs) also attenuated renal fibrosis to the same extent as 1%O2 rMSCs. Flow cytometry showed that 1%O2 hMSCs did not change human leukocyte antigen expression. Further in vitro experiments revealed that conditioned medium from 1%O2 MSCs further suppressed TGF-β1-induced fibrotic changes in HK-2 cells compared with 21%O2 MSCs. Hypoxic preconditioning enhanced vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF) secretion. Interestingly, VEGF knockdown in 1%O2 MSCs attenuated HGF secretion and the inhibition of TGF-β1-induced fibrotic changes in HK-2 cells. In addition, VEGF knockdown in 1%O2 hMSCs reduced the anti-fibrotic effect in IRI rats. Our results indicate that hypoxia-preconditioned MSCs are useful as an allogeneic transplantation cell therapy to prevent renal fibrosis and inflammation.

中文翻译：

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缺氧预处理的间充质干细胞可预防缺血再灌注大鼠的肾纤维化和炎症。

据报道，间充质干细胞 (MSCs) 通过其旁分泌能力促进受损组织的再生，缺氧预处理可增强这种旁分泌能力。在这项研究中，我们检查了缺氧预处理的 MSCs 对缺血再灌注损伤 (IRI) 大鼠肾纤维化和炎症的治疗效果。来自大鼠和人类的 MSCs 在 1% O2 条件下（1%O2 MSCs）孵育 24 小时。在 IRI 后，通过腹主动脉注射 1%O2 MSCs 或在常氧条件下培养的 MSCs（21%O2 MSCs）。在注射后 7 或 21 天，处死大鼠并分析它们的肾脏。在体外实验中，我们检查了使用转化生长因子 (TGF)-β1 刺激的 HK-2 细胞与来自 MSCs 的条件培养基一起培养的 1%O2 MSCs 是否增强了产生抗纤维化体液因子的能力。给予大鼠 1%O2 MSCs (1%O2 rMSCs) 比大鼠 21%O2 MSCs 更显着地减轻肾纤维化和炎症。值得注意的是，人 1%O2 MSCs (1%O2 hMSCs) 也可以将肾纤维化减弱到与 1%O2 rMSCs 相同的程度。流式细胞术显示 1%O2 hMSCs 不会改变人类白细胞抗原的表达。进一步的体外实验表明，与 21% O2 MSCs 相比，来自 1% O2 MSCs 的条件培养基进一步抑制了 TGF-β1 诱导的 HK-2 细胞纤维化变化。缺氧预处理增强了血管内皮生长因子 (VEGF) 和肝细胞生长因子 (HGF) 的分泌。有趣的是，1%O2 MSCs 中的 VEGF 敲低减弱了 HGF 分泌和抑制 TGF-β1 诱导的 HK-2 细胞纤维化变化。此外，1%O2 hMSCs 中的 VEGF 敲低降低了 IRI 大鼠的抗纤维化作用。我们的研究结果表明，缺氧预处理的 MSC 可用作同种异体移植细胞疗法，以预防肾纤维化和炎症。