Bifidobacteria are the most prevalent members of the intestinal microbiota in mammals and other animals, and they play a significant role in promoting gut health through their probiotic effects. Recently, the potential applications of Bifidobacteria have been extended to skin health. However, the beneficial mechanism of Bifidobacteria on the skin barrier remains unclear. In this study, keratinocyte HaCaT cells were used as models to evaluate the protective effects of the cell-free supernatant (CFS), heat-inactivated bacteria, and bacterial lysate of Bifidobacterium animalis CGMCC25262 on the skin barrier and inflammatory cytokines. The results showed that all the tested samples were able to upregulate the transcription levels of biomarker genes associated with the skin barrier, such as hyaluronic acid synthetase (HAS) and aquaporins (AQPs). Notably, the transcription of the hyaluronic acid synthetase gene-2 (HAS-2) is upregulated by 3~4 times, and AQP3 increased by 2.5 times when the keratinocyte HaCaT cells were co-incubated with 0.8 to 1% CFS. In particular, the expression level of Filaggrin (FLG) in HaCaT cells increased by 1.7 to 2.7 times when incubated with Bifidobacterial samples, reaching its peak at a concentration of 0.8% CFS. Moreover, B. animalis CGMCC25262 also decreased the expression of the proinflammatory cytokine RANTES to one-tenth compared to the levels observed in HaCaT cells induced with tumor necrosis factor alpha (TNF-α) and interferon gamma (IFN-γ). These results demonstrate the potential of B. animalis CGMCC25262 in protecting the skin barrier and reducing inflammatory response.

双歧杆菌是哺乳动物和其他动物肠道微生物群中最常见的成员，它们通过益生菌作用在促进肠道健康方面发挥着重要作用。最近，双歧杆菌的潜在应用已扩展到皮肤健康。然而，双歧杆菌对皮肤屏障的有益机制仍不清楚。本研究以角质形成细胞HaCaT细胞为模型，评价动物双歧杆菌CGMCC25262的无细胞上清液（CFS）、热灭活细菌和细菌裂解物对皮肤屏障和炎症细胞因子的保护作用。结果显示，所有测试样品都能上调与皮肤屏障相关的生物标志物基因的转录水平，例如透明质酸合成酶（HAS）和水通道蛋白（AQP）。值得注意的是，当角质形成细胞HaCaT细胞与0.8%~1%CFS共孵育时，透明质酸合成酶基因2（HAS-2）的转录上调3~4倍，AQP3增加2.5倍。特别是，当与双歧杆菌样品一起孵育时，HaCaT细胞中丝聚蛋白（FLG）的表达水平增加了1.7至2.7倍，在0.8% CFS浓度时达到峰值。此外，B . 与肿瘤坏死因子α（TNF-α）和干扰素γ（IFN-γ）诱导的HaCaT细胞中观察到的水平相比，动物CGMCC25262还将促炎细胞因子RANTES的表达降低至十分之一。这些结果证明了B的潜力。Animalis CGMCC25262 保护皮肤屏障和减少炎症反应。