| Abstract: | MethodsA mild inflammatory state was induced in female mice by dorsal surgical incision (DSI). Following DSI animals were orally supplemented with L. reuteri or vehicle control for a period of 8 weeks. Gene expression was measured in the intestine and bone marrow by qPCR. Distal femoral bone density and architecture was analyzed by micro-CT.ResultsWe report that 8 weeks after DSI there is a significant increase in the weight of spleen, thymus and visceral (retroperitoneal) fat pads. Expression of intestinal cytokines and tight junction proteins are also altered 8 weeks post-DSI. Interestingly, L. reuteri treatment was found to display both intestinal region- and inflammation-dependent effects. Unexpectedly we identified that 1) L. reuteri treatment increased bone density in females but only in those that underwent DSI and 2) DSI benefited cortical bone parameters. In the bone marrow, dorsal surgery induced CD4+ T cell numbers, a response that was unaffected by L. reuteri treatment, whereas expression of RANKL, OPG and IL-10 were significantly affected by L. reuteri treatment.ConclusionOur data reveals a previously unappreciated effect of a mild surgical procedure causing a long-lasting effect on inflammatory gene expression in the gut and the bone. Additionally, we demonstrate that in intact female mice, the beneficial effect of L. reuteri on bone requires an elevated inflammatory status. |
