Prevention of bone loss by using Lactobacillus-fermented milk products in a rat model of glucocorticoid-induced secondary osteoporosis

Secondary osteoporosis is a common side effect of glucocorticoid treatments. The anti-osteoporotic role of two fermented milk products (FMPs), produced with Lactobacillus plantarum A41 and Lactobacillus fermentum SRK414, in alleviating secondary osteoporotic symptoms induced by dexamethasone (Dex) injection in rats was investigated. The two FMPs could prevent Dex-induced bone loss in rats. The two FMPs normalised altered gene expression levels of bone metabolism-related markers (osteoprotegerin, osteocalcin, bone sialoprotein, receptor activator of nuclear factor kappa-B ligand, and tartrate-resistant acid phosphatase). Furthermore, they regulated gene expression levels of bone morphogenetic protein 2-related and cell apoptosis markers in the tibia and calcium metabolism-related markers in the ileum. Additionally, these treatments modulated faecal bacterial populations by increasing Lactobacillus colonies. FMPs fermented by L. plantarum A41 and L. fermentum SRK414 were capable of preventing glucocorticoid-induced secondary osteoporosis via regulation of intestinal microbiota and gene expression levels of bone cell apoptosis related markers.