Midkine Promotes Odontoblast-like Differentiation and Tertiary Dentin Formation.

Autophagy is an intracellular self-degradation process that is essential for tissue development, cell differentiation, and survival. Nevertheless, the role of autophagy in tooth development has not been definitively identified. The goal of this study was to investigate how autophagy is involved in midkine (MK)-mediated odontoblast-like differentiation, mineralization, and tertiary dentin formation in a mouse tooth pulp exposure model. In vitro studies show that MK and LC3 have similar expression patterns during odontoblast-like cell differentiation. Odontoblast-like cell differentiation is promoted through MK-mediated autophagy, which leads to increased mineralized nodule formation. Subcutaneous transplantation of hydroxyapatite/tricalcium phosphate with rMK-treated human dental pulp cells led to dentin pulp-like tissue formation through MK-mediated autophagy. Furthermore, MK-mediated autophagy induces differentiation of dental pulp cells into odontoblast-like cells that form DSP-positive tertiary dentin in vivo. Our findings may provide 1) novel insight into the role of MK in regulating odontoblast-like differentiation and dentin formation in particular via autophagy and 2) potential application of MK in vital pulp therapy.

Effect of dietary prebiotic supplementation on the performance, intestinal microflora, and immune response of broilers.

This study investigated the effects of dietary supplementation with the prebiotics fructo-oligosaccharide (FOS) and mannan-oligosaccharide (MOS) on the performance, small intestinal microflora, and immune response of broilers. Two hundred forty 1-d-old Ross broiler chickens were randomly assigned to 6 dietary treatment groups: control, avilamycin (6 mg/kg), 0.25% FOS, 0.5% FOS, 0.025% MOS, and 0.05% MOS. Each treatment was fed to 4 replicates of 10 birds per diet for 4 wk. Except for the 0.5% FOS group, the overall BW gains of birds treated with avilamycin and prebiotics were significantly(P < 0.05) higher than those of the control group. No significant differences were found between the control and supplemented groups in overall feed intake, feed conversion, and mortality. The 0.05% MOS group was significantly (P < 0.05) lower than the control and 0.5% FOS groups in heterophil:lymphocyte ratio and basophil level. Concentrations of plasma IgA and IgG were not significantly different among the treatment groups. Quantitative real-time PCR indicated that supplementation of the diet with avilamycin or prebiotics caused significant (P < 0.05) changes in the small intestinal microbial community, as determined in samples obtained at the ileocecal junction. The populations of Clostridium perfringens and Escherichia coli decreased with 0.25% FOS, 0.05% MOS, or avilamycin, and lactobacilli increased in the 0.25% FOS and 0.25% MOS treatment groups. Total bacteria increased in the 0.25% FOS and 0.05% MOS treatments and decreased in the avilamycin treatment. Feeding 0.25% FOS and 0.05% MOS resulted in an increase in lactobacillus community diversity in the ileum. Our results showed that 0.25% FOS and 0.05% MOS were comparable with avilamycin in improving productivity in broilers raised in wire floor cages up to 28 d of age. Plasma immunoglobulins were not affected by prebiotics, but the heterophil:lymphocyte ratio, basophil level, and microbial population in the ileum were significantly affected.