蒲公英提取物对LPS诱导小鼠乳腺炎的减轻效应及其机制分析

旨在研究蒲公英提取物对内毒素（LPS）诱导小鼠乳腺炎的减轻效应及其机制分析。将小鼠随机分为空白组、模型组、阳性组和蒲公英提取物高、中、低剂量组。蒲公英提取物高、中、低剂量组分别按10.0、5.0、2.5 g·kg^-1灌胃给药，连续灌胃6 d，2次·d^-1，空白组灌胃等体积生理盐水。末次给药1 h后，于小鼠乳房基部分别灌注50 μL 0.2 mg·mL^-1 LPS，建立LPS诱导的小鼠乳腺炎模型，阳性组在建模后6和12 h腹腔注射5 mg·kg^-1地塞米松。24 h后取血，分离血清，剥离乳腺组织。ELISA法测定小鼠血清肿瘤坏死因子α（TNF-α）、白细胞介素-1β（IL-1β）和白细胞介素-6（IL-6）的含量，髓过氧化物酶（MPO）试剂盒测定小鼠血清MPO的含量，HE染色观察病理变化，Western blot法测定小鼠乳腺中TLR4蛋白以及NF-κB信号通路和MAPKs信号通路相关蛋白的表达。结果显示，蒲公英提取物高、中剂量组对LPS诱导的乳腺炎小鼠血清中TNF-α、IL-1β和IL-6的分泌有极显著抑制作用（P<0.01），极显著降低小鼠血清中MPO的含量（P<0.01）；蒲公英提取物高、中剂量组能改善LPS诱导的小鼠乳腺组织的病理变化，极显著下调LPS诱导的小鼠乳腺中TLR4、p-IκB、p-p65、p-p38、p-JNK、p-ERK蛋白的表达（P<0.01）。结果表明，蒲公英提取物通过调控NF-κB和MAPKs信号通路对LPS诱导的小鼠乳腺炎有明显减轻作用，为蒲公英的临床开发及应用奠定了基础。

Alleviating Effect and Mechanism of Dandelion Extract on LPS-Induced Mastitis in Mice

The purpose of this study was to study the alleviating effect of dandelion extract on lipopolysaccharide (LPS) induced mastitis in mice and its mechanism. The mice were divided into blank group, model group, positive group (DEX) and dandelion extract high, medium and low dose groups. Dandelion extract was administered at high, medium and low doses according to 10.0, 5.0, 2.5 g·kg^-1 gastric lavage, continuous gastric lavage for 6 days, 2 times per day, and the blank group was gastrically filled with equal volume of normal saline. One hour after the last administration, 50 μL of 0.2 mg·mL^-1 LPS was perfused in the basal part of the breast of mice to establish LPS-induced model of mastitis in mice, and the positive group was injected 5 mg·kg^-1 of dexamethasone intraperitoneally 6 and 12 h after modeling. Twenty-four hours later, blood was collected and serum was separated, and breast tissue was stripped. The contents of serum tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6) were determined by ELISA, the content of myeloperoxidase (MPO) was measured by MPO kit, the pathological change was observed by HE staining, the expressions of TLR4 protein and related proteins of NF-κB and MAPKs signaling pathways in mouse mammary glands were measured by Western blot. The results showed that dandelion extract at high and medium dose groups significantly inhibited the secretion of serum TNF-α, IL-1β and IL-6 (P<0.01), reduced MPO content in LPS-induced mastitis mice (P<0.01), and dandelion at high and medium dose groups extract improved pathological changes of mastitis induced by LPS, significantly down-regulated the expression of TLR4, p-IκB, p-p65, p-p38, p-JNK, p-ERK proteins in LPS-induced mastitis (P<0.01). The results showed that dandelion extract can significantly alleviate LPS induced mastitis by regulating NF-κB and MAPKs signaling pathways in mice, which lays a foundation for the clinical development and application of dandelion.