The aim of this study was to identify factors that regulate ruminal epithelial insulin‐like growth factor‐binding protein (IGFBP) expression and determine its role in rumen epithelial cell proliferation. Primary bovine rumen epithelial cells (BREC) were incubated with short‐chain fatty acids (SCFAs) at pH 7.4 or 5.6, lactate, lipopolysaccharide (LPS), insulin‐like growth factor‐I (IGF‐I), ‐II (IGF‐II), or recombinant bovine IGFBP2 (rbIGFBP2). The mRNA expression levels of IGFBP in BREC were analyzed using quantitative real‐time polymerase chain reaction (qRT‐PCR). The proliferation rate of BREC was analyzed using a WST‐1 assay. IGFBP2 gene expression tended to be lower with SCFA treatment (p  < .1), and IGFBP6 gene expression was significantly lower with SCFA treatment (p  < .05). IGFBP3 and IGFBP6 gene expression tended to be higher with d ‐Lactate treatment (p  < .1). IGFBP3 gene expression was significantly higher (p  < .05) with LPS treatment. BREC treated with IGF‐I grew more rapidly than vehicle control‐treated cells (p  < .01); however, recombinant bovine rbIGFBP2 inhibited IGF‐I‐induced proliferation. IGF‐II and/or rbIGFBP2 did not affect BREC proliferation. Taken together, SCFA treatment decreased IGFBP2 and IGFBP6 expression in rumen epithelial cells, and lower expression of these IGFBP might promote rumen epithelial cell proliferation by facilitating IGF‐I.

中文翻译：

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瘤胃上皮胰岛素样生长因子结合蛋白 2、3 和 6 与上皮细胞增殖有关。

本研究的目的是确定调节瘤胃上皮胰岛素样生长因子结合蛋白 (IGFBP) 表达的因素，并确定其在瘤胃上皮细胞增殖中的作用。原代牛瘤胃上皮细胞 (BREC) 与 pH 7.4 或 5.6 的短链脂肪酸 (SCFA)、乳酸、脂多糖 (LPS)、胰岛素样生长因子-I (IGF-I)、-II (IGF- II), 或重组牛 IGFBP2 (rbIGFBP2)。使用定量实时聚合酶链反应 (qRT-PCR) 分析 BREC 中 IGFBP 的 mRNA 表达水平。使用 WST-1 测定法分析 BREC 的增殖率。IGFBP2基因表达在 SCFA 处理下趋于降低 ( p  < .1)，而IGFBP6SCFA 处理的基因表达显着降低 ( p  < .05)。d-乳酸处理后IGFBP3和IGFBP6基因表达趋于更高( p  < .1)。 LPS 处理的IGFBP3基因表达显着更高 ( p < .05)。用 IGF-I 处理的 BREC 比载体对照处理的细胞生长得更快 ( p  < .01)；然而，重组牛 rbIGFBP2 抑制了 IGF-I 诱导的增殖。IGF-II 和/或 rbIGFBP2 不影响 BREC 增殖。总之，SCFA 治疗降低了IGFBP2和IGFBP6IGFBP在瘤胃上皮细胞中的表达，以及这些IGFBP的较低表达可能通过促进 IGF-I 促进瘤胃上皮细胞增殖。