PM2.5-induced inflammation and myocardial cell injury in rats.

OBJECTIVE: Numerous studies show association of particular matter (PM) in air pollution with cardiovascular dysfunction, and increased morbidity and mortality. The main mechanisms of this adverse effect involve increasing oxidative stress, inflammatory responses, and genotoxicity. Several recent studies investigated the ability of PM2.5 to cause myocardial injury in animal models using various methods, such as intratracheal instillation, intraperitoneal injection or tail vein injection. The purpose of this study is to explore the PM2.5-induced myocardial inflammatory reaction in rats through the new technology of multi-functional aerosol concentration and enrichment system. MATERIALS AND METHODS: Thirty Wistar rats were divided into two groups, 15 in each group. In the exposure group, PM2.5 multi-functional aerosol concentration and enrichment system was used for PM2.5 online oral and nasal exposure (5 times a week, 4 hours exposure, for the duration of 3 months). Histopathological examination of the left ventricular myocardial tissue of both groups was done using hematoxylin and eosin (H&E) staining. Ultrastructural changes of the heart specimens were assessed using electron microscopy. The levels of CRP and ICAM-1 were detected by immunohistochemistry. RESULTS: Compared with the control group, myocardial tissue of the exposure group exhibited edema, widened myocardial space and infiltration of inflammatory cells. There was nuclear pyknosis, mitochondrial membrane and spinal fusion, rough endoplasmic reticulum expansion, degranulation and cell swelling in the exposed group. The area of CRP positive staining in the exposed group was 3.7-fold higher than that in the control group (p < 0.05), and the ICAM-1 positive staining area of the exposed group was 12-fold higher than that of the control group (p < 0.05). CONCLUSIONS: Prolonged exposure to PM2.5 inhalation promotes significant upregulation of ICAM-1 and CRP expression in myocardial tissues, ultrastructural alterations in myocardial cells, and influx of inflammatory cells.

[Three-dimensional finite element analysis of different framework materials in implant-supported fixed mandibular prosthesis].

Objective: To evaluate the biomechanical behaviors of different framework materials in implant-supported fixed mandibular prosthesis using three-dimensional finite element analysis. Methods: A model of implant-supported fixed mandibular prosthesis was established. The simulations were divided into six groups according to the framework materials: pure titanium, cobalt-chromium alloy, gold alloy, zirconia, polyether ether ketone (PEEK) and carbon fiber-reinforced PEEK. An oblique load of 300 N with a 75° angle to the occlusal plane was applied from the lingual side on the buccal cusps of the two premolars and the first molar teeth. The stresses on implants, surrounding bones and frameworks were analyzed and compared among the framework materials both quantitatively and qualitatively. Results: In implant-supported fixed mandibular prosthesis model, the highest stresses were located around the neck of the implants and cortical bone during oblique loading among six designs. In addition, the stresses were concentrated on the buccal and distal cortical bone around the implants of the posterior region. Stress values of implants and cortical bones from low to high were as follows: zirconia, cobalt-chromium alloy, pure titanium, gold alloy, carbon fiber-reinforced PEEK, PEEK. The von Mises stress values of implant and cortical bone in the first molar site of PEEK framework material were 44.96 and 29.13 MPa, while the von Mises stress values of implant and cortical bone in the first molar site of zirconia framework material were 21.29 and 17.79 MPa. The zirconia and medal framework materials were more advantageous in stress distribution around implants than PEEK framework material. Conclusions: In implant-supported fixed mandibular prostheses, biomechanical analysis showed that the zirconia and medal framework materials were more advantageous in stress distribution around implants than PEEK framework materials.

[Clinical follow-up observation of 84 cases of implant-retained/supported prostheses in edentulous patients].

Objectives: To evaluate the long-term clinical results and patient satisfaction of implant-retained/supported prostheses in edentulous patient based on retrospectively summary of the clinical data of implant-retained/supported prostheses patients. Methods: Edentulous patients who received implant denture treatment between 01/2005 and 12/2016 was included in this study. Soft tissue health, clinical examination, X-ray observation, patient satisfaction with implant-retained/supported prostheses were evaluated. Results: A total of 400 implants in 84 cases (96 jaws), 35 fixed bridges and 61 overdentures. The follow-up time was (34.3±25.5) months. The 3- and 5-year implant cumulative survival rate of implant-supported overdenture was 95.0% and 92.1%, and the 3- and 5- year survival rate of implant-supported fixed denture was both 99.9%. The prevalence of peri-implantitis was 2.8% (11/400). A total of 44% (27/61) of the overdenture and 23%(8/35) of the fixed denture were repaired due to the complications of prosthesis. The mean repair frequency was (1.4±1.2) in overdenture and (1.3±0.9) in fixed denture (t=0.490, P=0.600). The average probing depth around implant recorded in the overdenture group [(2.2±1.1) mm] was significantly greater than that in the fixed denture group [(1.4±1.2) mm] (t=3.300, P=0.002). Patient satisfaction with an average of (6.5±4.9) in implant-support overdenture group was significantly higher than that in implant-support fixed denture group (3.2±2.8) (t=3.218, P=0.006). Conclusions: The complication rate of the prosthesis was high in edentulous patients with implant-retained/supported prostheses. Besides, the patients with implant supported denture expressed more satisfaction with their prostheses. And there was a relatively high implant cumulative survival rate of implant-retained/supported prostheses in edentulous patient.

Primary cilium is required for the stimulating effect of icaritin on osteogenic differentiation and mineralization of osteoblasts in vitro.

OBJECTIVE: Icaritin, one effective metabolite of Herba Epimedii-derived flavonoid icariin, has a strong osteogenic activity. However, its action mechanism remains unclear. Since primary cilia have been shown to play a pivotal role in regulating the osteogenesis, we hypothesized primary cilia are indispensable in mediating icaritin osteogenic effect. MATERIALS AND METHODS: Primary rat calvarial osteoblasts were transfected with siRNA1 targeting intraflagellar transport protein 88 (IFT88), a protein required for ciliogenesis, to prevent formation of primary cilium and were treated with 10-6 M icaritin. RESULTS: Alkaline phosphatase (ALP) activity was significantly increased after 3 days in cells transfected with scrambled siRNA control and treated by icaritin (SC+I group) compared to cells transfected with scrambled siRNA control only (SC group). ALP activity after IFT88 siRNA1 transfection and icaritin treatment (siRNA1+I group) was significantly lower than that of SC+I group. Formation of ALP positively stained colonies after 6 days, osteocalcin secretion after 9 days and formation of calcified nodules after 12 days displayed a similar tendency among the three groups. mRNA expression of osteogenesis-related genes ALP, BMP-2, COL1α, RUNX-2 and OSX after 24 h was significantly increased in SC+I group, but was not different with SC group in siRNA1+I group. Protein levels of BMP-2, COL1α, RUNX-2 and OSX after 48 h showed the similar tendency with gene expression. CONCLUSION: Primary cilia are important in mediating icaritin-stimulated osteogenic differentiation and may be a novel target for pharmacological therapies for bone loss.

Icariin attenuates hypoxia-induced oxidative stress and apoptosis in osteoblasts and preserves their osteogenic differentiation potential in vitro.

OBJECTIVES: Icariin, a prenylated flavonol glycoside isolated from traditional Chinese medicinal herb of the genus Epimedium, has been demonstrated to be a potential alternative therapy for osteoporosis, and its action mechanism so far has been mainly attributed to its phytoestrogenic property. As blood supply to bone is considerably reduced with ageing and by the menopause, we hypothesized that icariin treatment would reduce bone loss by preventing ischaemia-induced hypoxic damages to bone. MATERIALS AND METHODS: To investigate effects of icariin treatment on cultured rat calvarial osteoblasts exposed to hypoxic conditions (2% oxygen). RESULTS: Compared to normoxic control, cell viability decreased with time to 50% by 48 h in the hypoxic group, and icariin attenuated the reduction, dose dependently, with 10(-6) and 10(-5)  m concentrations showing significant protective effects. Icariin also inhibited increase of lactate dehydrogenase activity in culture media. Measurements on oxidative stress, cell cycling and cell survival indicated that icariin protected osteoblasts by reducing production of reactive oxygen species and malondialdehyde, increasing superoxide dismutase activity, arresting the cell cycle and inhibiting apoptosis. Icariin also preserved osteogenic differentiation potential of the hypoxic cells in a dose-dependent manner, compared to the hypoxia alone group, as revealed by increased levels of RUNX-2, OSX and BMP-2 gene expression, alkaline phosphatase activity, and formation of mineralized nodules. CONCLUSIONS: Our results demonstrated that icariin attenuated oxidative stress and apoptosis and preserved viability and osteogenic potential of osteoblasts exposed to hypoxia in vitro, and suggested that its anti-osteoporotic effect may be attributed to its anti-hypoxic activity and phytoestrogenic properties.

A clinical study on the effectiveness of implant supported dental restoration in patients with chronic periodontal diseases.

This study evaluated the efficacy of implant supported dental restorations in patients with chronic periodontal diseases at various stages within 2 years of completing treatment. 30 patients with periodontal diseases and 30 patients without periodontal diseases were studied. Total counts of 276 implant bodies were divided into group A (patients with periodontal diseases; a total of 149 implants) and group B (patients with healthy periodontium; a total of 127 implants). In group A subjects, periodontitis was treated prior to implant placement. The study focused on patients' modified sulcus bleeding index, modified plaque index, implant mobility index, periodontal probing depth and implant success rate 12 and 24 months after the completion of the treatment. The result show: there were no significant differences in implant success rate between groups A and B; modified sulcus bleeding index scores showed differences between the groups 24 months after treatment; there were no significant differences in other clinical indexes during the study between the groups; there were no significant differences in periodontal probing depth between the groups; modified plaque index and modified sulcus bleeding index were positively correlated in implant supported dental restoration patients with chronic periodontal diseases.

Inhibition of hepatic microsomal enzymes by gossypol in the rat.

The effect of the male contraceptive, gossypol, on rat liver microsomal enzymes has been studied in vitro and in vivo. In vitro, gossypol inhibited aminopyrine N-demethylase activity, the concentration causing 50% inhibition being approximately 0.03 mM; the inhibition was non-competitive. Also the metabolism of ethinylestradiol (a drug with a number of metabolic pathways) was inhibited with the main effect being reduced 2- and 16-hydroxylation. In vivo, gossypol, after 4 weeks of daily administration (30 mg/kg/day) caused a significant reduction in microsomal protein, cytochrome P450 and aminopyrine N-demethylase activity. However, despite reduced enzyme activity, the metabolism of tolbutamide (a drug with a single pathway of metabolism and hence a model substrate) was not impaired by either acute or chronic gossypol administration.