BACKGROUND:Nano-zirconium dioxide has good application potential in the field of bone tissue repair.Studying the effect of nano-zirconium dioxide on osteogenic differentiation will help to promote the clinical application of nano-zirconium dioxide in the treatment of bone defects. OBJECTIVE:To explore the effect of nano-zirconium dioxide on the osteogenic differentiation of ectomesenchymal stem cells in the nasal mucosa. METHODS:Ectomesenchymal stem cells derived from rat nasal mucosa were isolated and cultured,and the biotoxicity of nano-zirconium dioxide to the cells was detected by CCK-8 assay.The biosafety concentration was selected according to the cytotoxicity,and the cells were randomly divided into a control group,a nano-zirconium dioxide group,and a nano-hydroxyapatite group.Osteogenic differentiation of cells was directionally induced in each group.On day 7 of induced differentiation,alkaline phosphatase staining was performed.qRT-PCR and western blot assay were used to detect the expression of early osteogenic markers(Runx2 and Osx).On day 21 of induced differentiation,alizarin red staining was conducted.qRT-PCR and western blot assay were utilized to determine the expression levels of late osteogenic markers(OPN and OCN). RESULTS AND CONCLUSION:(1)The median lethal concentration of nano-zirconium dioxide on ectomesenchymal stem cells in nasal mucosa was 0.6 mg/mL.In the experiment,the mass concentration of 200 μg/mL was selected for intervention.Zirconium dioxide had no significant effect on the proliferation of the cells.(2)Compared with the control group,the alkaline phosphatase staining of the cells in the nano-zirconium dioxide group was more obvious and the level of cell mineralization was higher,but there was no significant difference compared with the nano-hydroxyapatite.(3)Compared with the control group,the expression of bone-related genes and proteins increased significantly,but there was no significant difference compared with nano-hydroxyapatite.(4)The results show that nano-zirconium dioxide has good biological safety and can promote the osteogenic differentiation of ectomesenchymal stem cells in the nasal mucosa.This promoting effect is equivalent to that of nano-hydroxyapatite.

OBJECTIVE：To study the repa ir effect and mechanism of Taohong siwu decoction on rotator cuff injury in rabbits. METHODS：New Zealand rabbits were randomly divided into blank control group ，model group ，Taohong siwu decoction low-dose，medium-dose and high-dose groups （2.75，5.5，11 g/kg），and Taohong siwu decoction+LY 294002 group [ 5.5 g/kg Taohong siwu decoction+ 6.4 μg/kg LY294002（pathway inhibitor ）]，with 11 rabbits in each group. Except for blank control group ， other groups underwent right subscapularis muscle detachment to establish rotator cuff injury model. After modeling ，blank control group and model group were given normal saline intragastrically ；Taohong siwu decoction groups were given relevant medicine intragastrically；Taohong siwu decoction+LY 294002 group was given Taohong siwu decoction intragastrically ，and then injected with LY 294002 at the ear edge ，once a day ，for 12 weeks. After last intragastric administration （injection），the pathological changes of tendon-bone interface was observed ；the levels of TNF-α，IL-10 and IL- 6 in serum were detected ；mRNA and protein expressions of PI 3K，Akt and mTOR in tendon-bone interface were detected ；the expression of autophagy related protein （Beclin1， LC3Ⅱ）were detected. RESULTS ：Compared with blank control group ，the tendon-bone interface was uneven and the intima was swollen in model group. Serum levels of TNF-α and IL-6，mRNA and protein expressions of PI 3K，Akt and mTOR in tendon-bone interface were increased significantly （P＜0.05 or P＜0.01），while the level of IL- 10 and protein expression of Beclin 1 and LC 3Ⅱ were decreased significantly （P＜0.01）. Compared with model group ，the tendon-bone interface of rabbits in Taohong siwu decoction low-dose and medium-dose groups still had certain intimal damage ，while the tendon-bone interface of rabbits in high-dose group was smooth and flat without an obvious intimal tear ；the levels of most indexes in serum and tendon-bone interface of rabbits were significantly reversed in each dose group （P＜0.05 or P＜0.01）. Swollen tendon-bone interface and obvious intimal tear were obse rved in Taohong siwu decoction + LY group；compared with model group ，there w as no significant difference in above indexes of serum and tendon-bone interface （P＞0.05）. CONCLUSIONS ：Taohong siwu decoction may repair the rotator cuff injury of rabbits ，the mechanism of which may be associated with inhibiting PI3K/Akt/mTOR signaling pathway，activating autophagy and inhibiting inflammatory response.