Pinoresinol diglucoside mitigates dexamethasone-induced osteoporosis and chondrodysplasia in zebrafish.

BACKGROUND: The global increase in the aging population has led to a higher incidence of osteoporosis among the elderly. OBJECTIVE: This study aimed to evaluate the protective properties of pinoresinol diglucoside (PDG), an active constituent of Eucommia ulmoides, against dexamethasone-induced osteoporosis and chondrodysplasia. METHODS: A zebrafish model of osteoporosis was established by exposing larval zebrafish to dexamethasone. The impact of PDG on bone mineralization was assessed through alizarin red and calcein staining. Alkaline phosphatase activity was quantified to evaluate osteoblast function. The influence of PDG on chondrogenesis was estimated using alcian blue staining. Fluorescence imaging and motor behavior analysis were employed to assess the protective effect of PDG on the structure and function of dexamethasone-induced skeletal teratogenesis. qPCR determined the expression of osteogenesis and Wnt signaling-related genes. Molecular docking was used to assess the potential interactions between PDG and Wnt receptors. RESULTS: PDG significantly increased bone mineralization and corrected spinal curvature and cartilage malformations in the zebrafish model. Furthermore, PDG enhanced swimming abilities compared to the model group. PDG mitigated dexamethasone-induced skeletal abnormalities in zebrafish by upregulating Wnt signaling, showing potential interaction with Wnt receptors FZD2 and FZD5. CONCLUSION: PDG mitigates dexamethasone-induced osteoporosis and chondrodysplasia by promoting bone formation and activating Wnt signaling.

Benzalkonium chloride induces hematopoietic stem cell reduction and immunotoxicity in zebrafish larvae.

Benzalkonium chloride (BAC) is a broad-spectrum antibacterial agent that possesses cleaning and bactericidal properties, but impact of BAC on wellbeing of aquatic organisms remains uncertain. Consequently, in this current study, we have examined the immunotoxic potential of BAC in zebrafish embryos, thus marking it as the pioneering effort in this field. According to the findings, zebrafish embryos exposed to BAC exhibited a decline in yolk area that varied with the concentration, along with a significant decrease in the count of neutrophils, macrophages, red blood cells, and thymus T-cells. We observed significantly up-regulated expression of immune-related signaling genes such as cxcl-c1c, il-8, tir4 and inf-γ, but expression of nf-κb was downregulated. In addition, we observed a marked reduction in the number of hematopoietic stem cells in zebrafish larvae after BAC exposure, which could be the result of oxidative stress-mediated apoptosis. We found that compared with the control group, the number of red blood cells in juvenile zebrafish in BAC-exposure group was significantly down-regulated, which could be attributed to hematopoietic stem cell defect. Astaxanthin restored immune cells and hematopoietic stem cells after BAC exposure, whereas Inhibitor of Wnt Response-1(IWR-1) restored neutrophils after BAC exposure. The research findings demonstrated that exposure to BAC displayed harmful effects on the development and immune system of zebrafish embryos. These effects might be associated with alterations in reactive oxygen species(ROS) levels and activation of the Wnt signaling pathway caused by BAC.

Settling effect of abutment and torque loss in different types of abutment after cyclic loading.

OBJECTIVES: This study aimed to evaluate and compare the settling effect of implant-abutment assembly and the torque loss before and after cyclic loading in three types of abutments. METHODS: Thirty internal hexagon fixtures were randomly divided into three groups (n=10). Group A used original abutments, group B used pre-machined cast abutments, and group C used compatible abutments. In addition, the abutment morse taper angle was measured using an image measuring instrument. Removal torque values (RTVs) were recorded using a digital torque meter before and after cyclic loading. All samples were tested in a universal testing machine with a vertical load between 0 and 250 N for 100 000 cycles of 10 Hz. The settling effect was measured after cyclic loading. Paired t test was performed for intragroup analysis of removal torque loss before and after cycling and one-way ANOVA. Subsequently, Tukey's honestly significant difference test was used for intergroup comparison (α=0.05). RESULTS: The paired t-test showed signi⁃ficant differences in the intragroup RTVs before and after cycling (P<0.001). ANOVA showed significant differences in the mean of removal torque loss after cycling (P=0.009), the abutment morse taper angle (P<0.001), and the settling values (P=0.01) among different groups. However, no significant difference was found between compatible abutments and pre-machined cast abutments. CONCLUSIONS: The screw removal torque was significantly reduced for all groups in this study after cyclic loading. Differences could be found in the internal accuracy of implant-abutment assembly among different groups. Within the limitations of this study, the results showed the original abutments exhibited lower percentages of torque reduction after cyclic loading than the casting abutments and the compatible abutments.