探索间充质干细胞（MSC）外泌体提高低氧条件下胰岛β细胞活性的潜在分子机制。

将小鼠胰岛β细胞分别培养于常氧环境（5% CO₂，95%空气）、低氧环境（2%O₂，5%CO₂，93%N₂）以及低氧环境添加MSC外泌体（50 μg/mL）。采用CCK-8检测试剂盒测定小鼠胰岛β细胞活性、细胞凋亡检测试剂盒分析小鼠胰岛β细胞凋亡情况；通过小鼠Arraystart LncRNA微阵列芯片分析不同培养环境下lncRNA和mRNA的表达情况；以Arraystart LncRNA微阵列芯片检测结果为生物信息学分析数据来源，基于t检验并设置显著性阈值P ≤0.05和｜Fold Change｜≥2为筛选标准，筛选并获得差异表达显著的lncRNA和mRNA，采用Pearson相关系数法分析样本间lncRNA与mRNA表达情况的相关性以明确差异lncRNA的潜在靶基因，进而通过对上述靶基因进行GO和KEGG富集分析，来探究MSC外泌体通过哪条信号通路在低氧条件下增强小鼠胰岛β细胞抗低氧损伤能力。两组间数据比较采用t检验，三组间进行单因素方差分析，然后进行Dunnett's-t多重比较分析。

CCK-8结果显示，与常氧条件相比，低氧条件下小鼠胰岛β细胞OD值（0.44 ± 0.02比0.53 ± 0.01）下降（t = 4.455，P < 0.05）。凋亡分析结果显示，与常氧培养相比，低氧条件下小鼠胰岛β细胞凋亡率（33.03% ± 3.12%比11.27% ± 2.69%）升高（t = 5.289，P < 0.01）。低氧培养条件下加入MSC来源外泌体干预后，小鼠胰岛β细胞活性OD值较单纯低氧培养（0.42 ± 0.03比0.33 ± 0.01）升高（P < 0.01）；小鼠胰岛β细胞凋亡率较低氧培养（15.23% ± 0.62%比32.63 % ± 0.95%）降低（P < 0.01）。利用LncRNA微阵列芯片完成小鼠胰岛β细胞中35 293个lncRNA和24 881个mRNA表达水平的检测，结果显示，与常氧培养条件相比低氧培养条件可引起1 726个lncRNA和1 023个mRNA表达差异；与低氧培养条件相比，加入MSC来源外泌体干预后，491个lncRNA和406个mRNA表达差异。对两种不同培养条件下差异lncRNA和mRNA利用韦恩图分别取交集，最终获得均有表达差异的lncRNA 112个、mRNA 60个；进一步相关性分析提示这112个lncRNA存在1 582个潜在靶基因；进而对这些靶基因进行GO和KEGG富集分析，结果显示差异表达lncRNA靶基因主要与MAPK、自噬等信号通路等密切相关。

低氧可引起小鼠胰岛β细胞凋亡，MSC来源外泌体可提高低氧条件下β细胞活性，抑制低氧诱发的小鼠胰岛β细胞凋亡，这可能与lncRNA调控MAPK、自噬等信号通路有关。

This study aims to explore the potential mechanisms through which mesenchymal stem cell (MSC) exosomes enhance the activity of pancreatic islet β-cells under hypoxic conditions.

Mouse pancreatic islet β-cells were cultured under three different conditions: normoxic (5% CO₂, 95% air) , hypoxic (2% O₂, 5% CO₂, 93% N₂) , and hypoxic conditions with MSC exosome (50 μg/mL) . The activity of β-cells was assessed using the Cell Counting Kit-8 (CCK-8) , while apoptosis was analyzed using a cell apoptosis detection kit. Differential expression of lncRNAs and mRNAs was investigated using Mouse Arraystar LncRNA microarray chips. Mouse Arraystar LncRNA microarray chips were used to analyze the differential expression of lncRNAs and mRNAs. Based on the chip analysis results, the t-test significance threshold was set at P≤0.05 and |Fold Change|≥2 to screen for differentially expressed lncRNAs and mRNAs. Pearson correlation coefficient analysis was used to analyze the correlation between lncRNAs and protein-coding genes among samples. Further enrichment analysis of GO and KEGG was conducted on the potential target genes corresponding to lncRNAs to explore the potential pathways of MSC exosome against hypoxia-induced β-cells apoptosis. T test was used for comparison between the two groups, One-way ANOVA was used for comparison among three groups, and then Dunnett's-t multiple comparison analysis was performed.

The CCK-8 results showed that under hypoxic conditions, the OD value of β-cells significantly decreased compared to normoxic conditions (0.44 ± 0.02 vs 0.53 ± 0.01) (t = 4.455, P < 0.05) , indicating decreased β-cell activity under hypoxic conditions. Apoptosis analysis showed that the apoptosis rate of β-cells under hypoxic conditions was significantly higher than that of the normoxic group (33.03%± 3.12%vs 11.27%± 2.69%) (t = 5.289, P < 0.01) . After intervention with MSC exosomes under hypoxic conditions, the activity of β-cells was significantly increased compared to the hypoxic group (OD value 0.42 ± 0.03 vs 0.33 ± 0.01) (P < 0.01) ; the apoptosis rate of β-cells was significantly decreased compared to the hypoxic group (15.23%± 0.62%vs 32.63%± 0.95%) (P < 0.01) . The LncRNA microarray chip was used to assess the expression levels of 35 923 lncRNAs and 24 881 mRNAs in mouse β-cells. Compared with the normoxic control group, hypoxia caused significant differences in the expression of 1 726 lncRNAs and 1 023 mRNAs; compared with the hypoxic group, addition of exosomes resulted in significant differences in the expression of 491 lncRNAs and 406 mRNAs. The intersection of differentially expressed lncRNAs and mRNAs under two comparison conditions yielded 112 shared lncRNAs and 60 shared mRNAs. Correlation analysis suggests that these 112 lncRNAs are associated with 1 582 potential target genes. GO and KEGG enrichment analysis of these target genes showed that differentially expressed lncRNA target genes were mainly associated with MAPK, autophagy, and other signaling pathways.

Hypoxia could induce apoptosis of β-cells, while MSC exosomes could enhance the activity of β-cells under hypoxic conditions and inhibit hypoxia-induced apoptosis of β-cells, possibly through lncRNA regulation of MAPK, autophagy, and other signaling pathways.