Obese animals and humans demonstrate higher sensitivity to pain stimuli. Among the endogenous factors prompting obesity, the intestinal microbiota has been proposed to influence responsiveness to pain. The beneficial effects of probiotics on obesity are well documented, whereas data on their analgesic efficacy is minimal. The protective effect of probiotics on nociception in diet-induced obese male mice has been previously demonstrated, but the sex differences in pain sensitivity and analgesic response do not allow for the generalization of these findings to the female gender. Hence, this study aimed at investigating the potential effects of oral probiotic supplementation on mechanical pain thresholds in female diet-induced obese mice compared with controls. Thirty-two adult female mice () were randomly divided into two groups receiving standard (normal-weight group; NW) or high-fat diet (diet-induced obesity; DIO). All rats received a single daily dose (1 × 10⁹ CFU) of probiotics (Lactobacillus rhamnosus PB01, DSM14870) for four weeks by gavage. Mechanical pain thresholds were recorded by an electronic von Frey device at baseline, at the end of weeks 2, 4, 6, and 8 in both DIO and NW groups with and without consumption of probiotics. Blood samples were obtained for the measurement of lipid profile and reproductive hormone levels. Bodyweight was considerably lower () in groups supplied with probiotics than groups without probiotics. Pressure pain threshold values showed a significant () increase (reduced pain sensitivity) following probiotic supplementation, proposing a modulatory effect of probiotics on mechanical sensory circuits and mechanical sensitivity, which might be a direct consequence of weight loss or an indirect result of the probiotics’ anti-inflammatory properties. Understanding the precise underlying mechanism for the effect of probiotics on weight loss and mechanical pain sensitivity seen in this study warrants further investigation.

中文翻译：

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益生菌鼠李糖乳杆菌 PB01 对女性饮食诱发肥胖模型机械敏感性的调节作用


肥胖动物和人类对疼痛刺激表现出更高的敏感性。在促进肥胖的内源性因素中，肠道微生物群被认为会影响对疼痛的反应。益生菌对肥胖的有益作用已有充分记录，但其镇痛功效的数据却很少。益生菌对饮食诱导的肥胖雄性小鼠伤害感受的保护作用已被证明，但疼痛敏感性和镇痛反应的性别差异不允许将这些发现推广到女性。因此，本研究旨在调查与对照组相比，口服益生菌补充剂对雌性饮食诱导的肥胖小鼠机械性疼痛阈值的潜在影响。三十二只成年雌性小鼠（ ）被随机分为两组，接受标准饮食（正常体重组；NW）或高脂肪饮食（饮食诱导肥胖；DIO）。所有大鼠均通过灌胃法接受每日单剂 (1 × 10 ⁹ CFU) 益生菌（鼠李糖乳杆菌PB01、DSM14870），持续 4 周。在服用或不服用益生菌的 DIO 组和 NW 组中，通过电子 von Frey 装置在基线、第 2、4、6 和 8 周结束时记录机械疼痛阈值。采集血样用于测量血脂和生殖激素水平。 体重显着降低（ ）在提供益生菌的组中比没有益生菌的组中。压痛阈值显示显着（ ）补充益生菌后增加（疼痛敏感性降低），提出益生菌对机械感觉回路和机械敏感性的调节作用，这可能是体重减轻的直接结果或益生菌抗炎特性的间接结果。了解本研究中发现的益生菌对减肥和机械疼痛敏感性影响的精确潜在机制值得进一步研究。