葉酸缺乏與瘦體素對發炎反應之影響

Effect of folate deficiency and leptin on inflammatory response

詹培萱(Pei-Hsuan Chan)

指導教授 ： 林璧鳳

國立臺灣大學/生命科學院/生化科技學系/碩士(2015年)

https://doi.org/10.6342/NTU201600253

摘要

瘦體素與食慾及能量代謝有關。葉酸為必頇營養素,參與核酸及蛋白質的合
成與代謝。本研究探討葉酸缺乏與瘦體素對發炎反應的影響,以及兩者間可能的
關聯。實驗分為三部分:
實驗一為探討葉酸缺乏對LPS致急性發炎小鼠發炎反應的影響,將 C57BL/6 公鼠分為葉酸缺乏組(NF-f0, 0 mg/kg folate)與葉酸一倍組(NF-f1, 2 mg/kg folate),於 26 週齡腹腔注射LPS,27 週齡腹腔注射LPS及LPS/leptin致急性發炎,結果顯示, 注射LPS/leptin時,NF-f0組的血清瘦體素顯著高於NF-f1組,而葉酸缺乏顯著提高 LPS與LPS/leptin致發炎的血清IL-1β含量。餵食 31 週後,37 週齡時犧牲,分析血 清促發炎細胞激素含量、肝臟與脂肪組織之發炎指標、脾臟中巨噬細胞、CD4+ T 細胞、Th1、Th2、Treg細胞比率以及腹腔抽取液中巨噬細胞比率,另以ConA、 ConA/leptin刺激脾臟細胞,LPS、LPS/leptin刺激腹腔細胞。結果顯示葉酸缺乏顯 著提高血清IL-1β、MCP-1與IFN-γ含量,亦有提高血清瘦體素、TNF-α及IL-6含量 之趨勢;葉酸缺乏顯著降低脂肪組織Foxp3表現量,顯著提升肝臟MCP-1及IL-1β 表現量、腹腔M1巨噬細胞比率與降低腹腔M2巨噬細胞比率,顯著提高脾臟TNF-α、 IL-6、IFN-γ與腹腔TNF-α、IL-6、MCP-1的分泌量。在ConA或LPS刺激下,瘦體素 的添加顯著提高小鼠脾臟IFN-γ與腹腔TNF-α的分泌量。
實驗二為探討葉酸缺乏與瘦體素對正常油脂飲食小鼠發炎反應的影響,將小 鼠分為NF-f0與NF-f1兩組,於餵食 18 週後,25 週齡時犧牲。結果顯示葉酸缺乏 顯著提高血清瘦體素與促發炎細胞激素之含量,顯著降低肝臟F4/80的表現量與脾 臟CD4+T細胞之比率,顯著提高脾臟TNF-α、IL-6、IFN-γ與腹腔TNF-α、IL-6、MCP-1、IL-1β的分泌量。在ConA、LPS刺激下,瘦體素的添加顯著提高小鼠脾臟IL-6與IFN-γ 的分泌量。
實驗三為探討葉酸缺乏與瘦體素對高油飲食小鼠發炎反應的影響,將小鼠分 為葉酸缺乏組(HF-f0, 0 mg/kg folate)與葉酸一倍組(HF-f1, 2 mg/kg folate),餵食 20 週後,25 週齡時犧牲。結果顯示葉酸缺乏顯著提高血清瘦體素與促發炎細胞激素 之含量、脂肪組織瘦體素與TNF-α表現量,顯著降低脂肪組織IL-1β、Foxp3及MRC1 表現量、肝臟IL-1β與MRC1表現量。葉酸缺乏顯著提高脾臟IL-2與腹腔TNF-α、IL-1β 的分泌量,而在LPS刺激下添加瘦體素,顯著提高小鼠脾臟與腹腔TNF-α、IL-6的 分泌量。
由以上實驗結果得知,葉酸缺乏時小鼠體內瘦體素與促發炎細胞激素含量會
提升,並且葉酸缺乏與瘦體素均可能促進發炎反應。

關鍵字

葉酸缺乏 ； 瘦體素 ； 促發炎細胞激素

並列摘要

Leptin plays a big role in metabolism and energy expenditure. Folate is an essential nutrient that involved in synthesis of nucleotide and protein. The present study is to investigate the role of folate deficiency and leptin in inflammatory response. There are three parts of the experiments:
In experiment I, to investigate the effect of folate deficiency on inflammatory response of mice under LPS- or LPS/leptin-injection, male C57BL/6J mice were
divided into NF-f0 (0 mg/kg folate), and NF-f1 (2 mg/kg folate). LPS and LPS/leptin were intraperitoneally injected into mice at 26- and 27-week-old. The results showed that serum leptin level in LPS/leptin-injected mice, serum IL-1β level in LPS- and LPS/leptin-injected mice were significantly higher in the NF-f0 group. After feeding for 31 weeks, 37-week-old mice were sacrificed. Serum leptin and pro-inflammatory cytokines level, inflammatory mediators in liver and adipose tissue, ratio of macrophage, CD4+ T cells, Th1, Th2, Treg in spleen, and ratio of macrophage in PEC, were analyzed. Splenocytes were stimulated with ConA or ConA/leptin, while PECs were stimulated with LPS or LPS/leptin. The results showed that folate deficiency enhanced serum IL-1β, MCP-1 and IFN-γ level, tended to enhance serum leptin, TNF-α and IL-6. Folate deficiency decreased Foxp3 mRNA expression in the adipose tissue, enhanced MCP-1, IL-1β mRNA in the liver and M1 macrophage ratio in PEC, decreased M2 macrophage ratio in PEC. Folate deficiency enhanced TNF-α, IL-6, IFN-γ secretion in splenocytes and TNF-α, IL-6, MCP-1 secretion in PEC. Furthermore, leptin addition induced IFN-γ secretion in splenocytes and TNF-α secretion in PEC.
In experiment II, to investigate the effect of folate deficiency on inflammatory response, mice were divided into NF-f0 and NF-f1. After feeding for 18 weeks, 25-week-old mice were sacrificed. The results showed that folate deficiency enhanced serum leptin and pro-inflammatory cytokines level, decreased F4/80 mRNA in the liver and CD4+T cell population in splenocytes, also enhanced secretion of TNF-α, IL-6, IFN-γ in splenocytes and TNF-α, IL-6, MCP-1, IL-1β in PEC. Besides, leptin addition enhanced secretion of IL-6 and IFN-γ under LPS or ConA stimulation in splenocytes.
In experiment III, to investigate the effect of folate deficiency on inflammatory response of mice fed high-fat diet, mice were divided into HF-f0 (0 mg/kg folate) and HF-f1 (2 mg/kg folate). After feeding for 20 weeks, 26-week-old mice were sacrificed. The results showed that folate deficiency enhanced serum leptin and pro-inflammatory cytokines level, enhanced leptin and TNF-α mRNA in the adipose tissue, decreased IL-1β, Foxp3 and MRC1 mRNA in the adipose tissue as well as IL-1β and MRC1 mRNA expression in the liver. Besides, leptin addition enhanced TNF-α and IL-6 secretion in both splenocytes and PEC under LPS stimulation.
In conclusion, folate deficiency enhanced serum leptin and pro-inflammatory cytokines level. Both folate deficiency and leptin may exacerbate inflammatory response.

並列關鍵字

folate deficiency ； leptin ； inflammatory cytokine

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