Gastroenterology Department, Tianjin Medical University General Hospital, Tianjin, China.
Department of Orthointernal, Tianjin Hospital, Tianjin, China.
Calcif Tissue Int. 2022 Aug;111(2):162-170. doi: 10.1007/s00223-022-00975-z. Epub 2022 May 26.
Intestinal absorption of vitamin D is an important way to improve the vitamin D level in senile osteoporosis (SOP). There is a link between oral probiotics and vitamin D, but the mechanism is still unclear. We aimed to evaluate whether Lactobacillus rhamnosus GG culture supernatant (LCS) can affect cholecalciferol absorption, transport, and hydroxylation in SOP, and explore underlying mechanisms. In the study, specific-pathogen-free SAMP6 mice were randomly divided into an experimental group administered undiluted LCS and a control group administered normal drinking water. Furthermore, levels of cholecalciferol absorption were compared between Caco-2 cells cultured with varying concentrations of cholecalciferol and stimulated with LCS or de Man, Rogosa, and Sharpe (MRS) broth (control). Similarly, LCS-stimulated HepG2 cells were compared with MRS-stimulated HepG2 cells. Finally, protein levels of VD transporters in small intestine tissues and Caco-2 cells, as well as vitamin D-binding protein and 25-hydroxylase in liver tissues and HepG2 cells, were detected by western blot. The results showed that plasma concentrations of cholecalciferol and 25OHD were higher in mice of the LCS group compared with the control group, and these values were positively correlated. With the addition of LCS, cholecalciferol uptake was increased with 0.5 μM or 10 μM cholecalciferol in the medium. Protein levels of CD36 and NPC1L1 were higher in the LCS group compared with the control group, while SR-BI protein was decreased, both in vitro and in vivo. In conclusion, LCS can promotes intestinal absorption cholecalciferol by affecting protein levels of VD transporters and improves 25OHD levels in SOP.
肠道吸收维生素 D 是提高老年性骨质疏松症（SOP）中维生素 D 水平的重要途径。口服益生菌与维生素 D 之间存在联系，但机制尚不清楚。我们旨在评估鼠李糖乳杆菌 GG 培养上清液（LCS）是否可以影响 SOP 中胆钙化醇的吸收、转运和羟化，并探讨潜在机制。在这项研究中，无特定病原体的 SAMP6 小鼠被随机分为实验组，给予未稀释的 LCS，对照组给予正常饮用水。此外，还比较了用不同浓度胆钙化醇培养的 Caco-2 细胞与用 LCS 或 de Man, Rogosa, and Sharpe（MRS）肉汤（对照）刺激的 Caco-2 细胞之间的胆钙化醇吸收水平。同样，比较了 LCS 刺激的 HepG2 细胞与 MRS 刺激的 HepG2 细胞。最后，通过 Western blot 检测小肠组织和 Caco-2 细胞中的 VD 转运蛋白以及肝组织和 HepG2 细胞中的维生素 D 结合蛋白和 25-羟化酶的蛋白水平。结果表明，与对照组相比，LCS 组小鼠的血浆胆钙化醇和 25OHD 浓度更高，且呈正相关。随着 LCS 的加入，培养基中添加 0.5μM 或 10μM 胆钙化醇时，胆钙化醇摄取增加。LCS 组 CD36 和 NPC1L1 蛋白水平高于对照组，而 SR-BI 蛋白水平在体外和体内均降低。综上所述，LCS 可通过影响 VD 转运蛋白的蛋白水平促进肠道胆钙化醇吸收，提高 SOP 中的 25OHD 水平。
