Apoptosis-promoting properties of miR-3074-5p in MC3T3-E1 cells under iron overload conditions.

BACKGROUND: Iron overload can promote the development of osteoporosis by inducing apoptosis in osteoblasts. However, the mechanism by which miRNAs regulate apoptosis in osteoblasts under iron overload has not been elucidated. METHOD: The miRNA expression profile in MC3T3-E1 cells under iron overload was detected by next generation sequencing. qRT-PCR was used to determine the expression of miR-3074-5p in MC3T3-E1 cells under iron overload. The proliferation of MC3T3-E1 cells was tested using CCK-8 assays, and apoptosis was measured using flow cytometry. The miRanda and TargetScan databases were used to predict the target genes of miR-3074-5p. Interaction between miR-3074-5p and the potential target gene was validated by qRT-PCR, luciferase reporter assay and western blotting. RESULTS: We found that iron overload decreased the cell viability and induced apoptosis of MC3T3-E1 cells. The results of next generation sequencing analysis showed that miR-3074-5p expression was significantly increased in MC3T3-E1 cells under iron overload conditions, which was confirmed by further experiments. The inhibition of miR-3074-5p attenuated the apoptosis of iron-overloaded MC3T3-E1 cells. Furthermore, the expression of Smad4 was decreased and was inversely correlated with miR-3074-5p expression, and overexpression of Smad4 partially reversed the viability inhibition of iron-overloaded MC3T3-E1 cells by relieving the suppression of ERK, AKT, and Stat3 phosphorylation, suggesting its regulatory role in the viability inhibition of iron-overloaded MC3T3-E1 cells. The luciferase reporter assay results showed that Smad4 was the target gene of miR-3074-5p. CONCLUSION: miR-3074-5p functions as an apoptosis promoter in iron-overloaded MC3T3-E1 cells by directly targeting Smad4.

Effect of high pressure homogenization treatment on the rheological properties of citrus peel fiber/corn oil emulsion.

BACKGROUND: Citrus fiber is a main component in the peel of citrus and contains natural dietary fiber. It is often used as a functional additive to improve the texture or nutritional property of food. It is also widely used to reduce the content of absorbable fat in sausages and other meat products, and to improve food stability as an emulsifier. In this research, the dynamic rheological properties (linear and non-linear) of citrus peel fiber/corn oil (CF/CO) emulsion system under high pressure homogenization (HPH) treatment was investigated. RESULT: Rheological results illustrated HPH treatment significantly increased the apparent viscosity of the emulsion, reduced the activation energy of the emulsion and distinctly improved the viscoelasticity of the emulsion. Meanwhile, HPH treatment increased the linear viscoelastic region of the sample, and the behavior of the emulsion converted from strain thinning (without HPH treatment) to weak strain overshoot (with HPH treatment). Lissajous curves indicated the viscosity of the sample increased first and then decreased with strain increasing and the third harmonic contributed much more to the first harmonic compared with the fifth harmonic. Chebyshev stress decomposition revealed that, as strain increased, the samples with HPH treatment showed internal-cycle strain hardening behavior first, then turned to internal-cycle softening behavior. CONCLUSION: HPH treatment can significantly improve the processing performance of CF/CO emulsion as well as the stability against large periodic oscillations in food processing. © 2020 Society of Chemical Industry.

[Finite element study of maxillary Le Fort-I osteotomy with rigid internal fixation].

OBJECTIVE: To study the biomechanical characteristic of maxillary Le fort- I osteotomy with rigid internal fixation (RIF) , so as to choose best fixation method. METHODS: The 3-dimensional finite element models of maxillary Le Fort-I osteotomy with 9 kinds of RIF methods were established. Then the models were divided into three groups to calculate the stress distribution of the maxilla and the displacement of bone segment under 3 kinds of occlusion condition. The fixation stability of the different RIF methods was evaluated. RESULTS: Under the incisor occlusion condition, the stress of the cranio maxillary complex transmits mainly along the nasal-maxillary buttress. Under the premolar and molar occlusion condition, the stress transmits along the alveolar process first, then turns to the nasal-maxillary and zygomatic-maxillary buttress. The focused stress position of the internal fixation system is at the connection between the screws and the plate and at the plate near the osteotomy line. Under the premolar occlusion condition, the displacement of bone segment with different RIF methods was (in a decreasing order) 0.396509 mm (with bio-absorbable plate), 0.148393 mm (with micro-plate ), 0.078436 mm (with mini-plate) in group 1; 0.188791 mm (fixing at the nasal-maxillary buttress), 0.121718 mm (fixing at the zygomatic-maxillary buttress), 0.078436 mm (fixing at the both buttress) in group 2; 0.091023 mm (with straight plate), 0.078436 mm (with L shape plate), 0.072450 mm (with Y shape plate), 0.065617 mm (with T shape plate) in group 3. CONCLUSIONS: The fixation stability of using the bio-absorbable plate in Le Fort-I osteotomy is less stable than using the titanium plate. Fixing at the zygomatic-maxillary buttress is more stable than at the naso-maxillary buttress. The fixation stability is different by using different shapes of plates.

[Establishment and primary analysis of the three-dimensional finite element model of mandibular bilateral sagittal split ramus osteotomy with rigid internal fixation].

OBJECTIVE: Establish the three-dimensional finite element models of mandibular bilateral sagittal split ramus osteotomy (BSSRO) with rigid internal fixation (RIF), for further study of BSSRO. METHODS: CT scanned technology and the finite element software (ANSYS) were used to establish the original three-dimensional model of mandible, modify the model to animate the BSSRO, then establish the model of RIF, last mesh the model to establish the finite element model of BSSRO with RIF. Apply 100 N occlusion force at the central incisor; calculate the stress distribution of the mandible and the RIF. RESULTS: Three-dimensional finite element models of BSSRO with RIF were established, such as miniplate model, bicortical fixation screw model. When biting with the incisor and fixed with upper plate, the stress of the medial screw position of the distal and medial segment of mandible is high. When fixed with bicortical fixation screw, the highest stress position located at the internal surface of the medial screw' s position of the distal segment of mandible. CONCLUSIONS: The mentioned methods proved feasible in establishing the finite element models of BSSRO with RIF . The models can be applied to the study of BSSRO with RIF.