Beneficial effects of a low-protein diet on host resistance to Paracoccidioides brasiliensis in mice.
Beneficial effects of a low-protein diet on host resistance to Paracoccidioides brasiliensis in mice.
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DOI：
10.1016/j.nut.2009.02.004
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发表时间：
2009-09
期刊：
影响因子：
4.4
通讯作者：
M. Oarada;K. Kamei;T. Gonoi;T. Tsuzuki;Takahito Toyotome;K. Hirasaka;T. Nikawa;Ayaka Sato;N. Kurita
中科院分区：
文献类型：
--
作者：
M. Oarada;K. Kamei;T. Gonoi;T. Tsuzuki;Takahito Toyotome;K. Hirasaka;T. Nikawa;Ayaka Sato;N. Kurita
目的虽然蛋白质营养不良会损害免疫功能，但最近的一些研究表明，限制蛋白质而不是营养不良有助于宿主防御入侵的病原体和癌症。为了建立寄主抗性的最适饲料，我们研究了不同饲料蛋白水平对寄主对巴西拟球藻抗性的影响。在用这种真菌攻击小鼠后，立即用三种不同水平(0%、1.5%或20%)的酪蛋白喂养小鼠。在感染后0-7天，测定小鼠脾和肝脏的抗真菌活性和促炎介质水平。结果1.5%酪蛋白饲料的小鼠脾和肝脏的抗真菌活性高于20%酪蛋白饲料的小鼠。饲喂0%酪蛋白饲料的小鼠脾抗真菌活性介于1.5%和20%酪蛋白饲料的抗真菌活性之间。感染后，与饲喂20%酪蛋白的小鼠相比，饲喂1.5%或0%酪蛋白的小鼠脾和肝脏IL-6和干扰素-γ水平、肝脏抗微生物蛋白(髓过氧化物酶、组织蛋白酶-G和弹力酶-2)水平以及肝脏促炎介质(白细胞介素18、趋化因子C-X-C基序配体10、核因子-κB、诱导型一氧化氮合酶和粒细胞巨噬细胞集落刺激因子)水平的增加幅度较小。
OBJECTIVEAlthough protein malnutrition impairs immune functions, several studies have recently shown that protein restriction without malnutrition is beneficial to host defenses against invading pathogens and cancer. In an effort to establish the optimum diet for host resistance, we investigated the effect of different dietary protein levels on host resistance to Paracoccidioides brasiliensis.METHODSMice were fasted for 2 days and then infected with P. brasiliensis. Immediately after challenge with this fungus, mice were refed on diets with three different levels (0%, 1.5%, or 20%) of casein. On days 0–7 after infection, antifungal activity and levels of proinflammatory mediators in the spleen and liver were measured.RESULTSMice refed on the 1.5% casein diet showed higher antifungal activity in the spleen and liver compared with mice on the 20% casein diet. The antifungal activity in the spleens of mice refed on the 0% casein diet was intermediate between the antifungal activities of those refed the 1.5% and 20% casein diets. After infection, increases in spleen and liver levels of interleukin-6 and interferon-γ, liver mRNA levels of antimicrobial proteins (myeloperoxidase, cathepsin-G, and elastase-2), and liver mRNA levels of proinflammatory mediators (interleukin-18, chemokine C-X-C motif ligand 10, nuclear factor-κB, inducible nitric oxide synthase, and granulocyte–macrophage colony-stimulating factor) were less profound in mice on the 1.5% or 0% casein diet compared with mice refed the 20% casein diet.CONCLUSIONThe present results suggest that protein restriction without malnutrition could be beneficial to host resistance to P. brasiliensis.