日本京都大学等机构研究人员日前联合发表报告说，定期给实验鼠喂食双歧杆菌，可使实验鼠比同类更长寿。
研究人员选取20只10个月大的实验鼠，每周3次给它们喂食双歧杆菌“LKM512”，每只实验鼠每次食用双歧杆菌约2000万个，相当于市场销售的酸奶150毫升所含菌量。而给对照组的实验鼠每次只进食生理盐水。
10个月大的实验鼠相当于人类30岁至34岁的年纪。喂食双歧杆菌一直持续到实验鼠相当于人类约70岁的时候。这时这些实验鼠的生存率达约80%，而对照组实验鼠的生存率只有约30%，差异明显。另外，定期被喂食双歧杆菌的实验鼠毛非常整齐，外观显得年轻。
另外，仅饮用生理盐水的实验鼠约有20%出现肿瘤或溃疡等疾病，而食用双歧杆菌的实验鼠则基本没有患这些病。
研究人员认为，摄入双歧杆菌使实验鼠肠道内多聚胺的量增加，有效抑制了肠道老化，并起到了抗炎症的作用。
研究人员表示，不光是“LKM512”，其他品种的双歧杆菌应该能产生同样的功效。
本项研究的相关成果已在新一期美国在线科学杂志《科学公共图书馆—综合卷》上发表。(生物谷 Bioon.com)
doi:10.1371/journal.pone.0023652
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Longevity in Mice Is Promoted by Probiotic-Induced Suppression of Colonic Senescence Dependent on Upregulation of Gut Bacterial Polyamine Production
Mitsuharu Matsumoto, Shin Kurihara, Ryoko Kibe, Hisashi Ashida, Yoshimi Benno2
Background Chronic low-grade inflammation is recognized as an important factor contributing to senescence and age-related diseases. In mammals, levels of polyamines (PAs) decrease during the ageing process; PAs are known to decrease systemic inflammation by inhibiting inflammatory cytokine synthesis in macrophages. Reductions in intestinal luminal PAs levels have been associated with intestinal barrier dysfunction. The probiotic strain Bifidobacterium animalis subsp. lactis LKM512 is known to increase intestinal luminal PA concentrations. Methodology/Principal Findings We supplemented the diet of 10-month-old Crj:CD-1 female mice with LKM512 for 11 months, while the controls received no supplementation. Survival rates were compared using Kaplan–Meier survival curves. LKM512-treated mice survived significantly longer than controls (P<0.001); moreover, skin ulcers and tumors were more common in the control mice. We then analyzed inflammatory and intestinal conditions by measuring several markers using HPLC, ELISA, reverse transcription-quantitative PCR, and histological slices. LKM512 mice showed altered 16S rRNA gene expression of several predominant intestinal bacterial groups. The fecal concentrations of PAs, but not of short-chain fatty acids, were significantly higher in LKM512-treated mice (P<0.05). Colonic mucosal function was also better in LKM512 mice, with increased mucus secretion and better maintenance of tight junctions. Changes in gene expression levels were evaluated using the NimbleGen mouse DNA microarray. LKM512 administration also downregulated the expression of ageing-associated and inflammation-associated genes and gene expression levels in 21-month-old LKM512-treated mice resembled those in 10-month-old untreated (younger) mice. Conclusion/Significance Our study demonstrated increased longevity in mice following probiotic treatment with LKM512, possibly due to the suppression of chronic low-grade inflammation in the colon induced by higher PA levels. This indicates that ingestion of specific probiotics may be an easy approach for improving intestinal health and increasing lifespan. Further studies are required to clarify its effectiveness in humans.
