OBJECTIVETo investigate a new method to construct tissue-engineering bone that will be applicable clinically.

METHODSThe cultured 5th generation rabbit bone marrow stroma osteoblasts (MSO) was dissolved in 3% sodium alginate solution (the final concentration of sodium alginate in the solution being 1%, and MSO, 5x10(6)/L), and then inoculated into prepared true bone ceramic (TBC) and gelatinized the bone by dribbling with calcium gluconate. The standard bone defect models were made in 48 adult New Zealand rabbit's both radius. Among the 48 rabbits, 24 were in Groups A and B, in which the left radius was implanted with gelatinized MSO-TBC (Group A) and right radius implanted with autograft-bone (Group B); and the other 24 were in control group whose left radius was implanted with non-gelatinized MSO-TBC (Group C) and right radius implanted with gelatinized TBC (Group D). Outcomes of the implanted bones were assessed by radiology, pathological histology, osteogenetic quantitative analysis, and biomechanics at 2, 4, 8, 12 weeks postoperatively.

RESULTSIn Groups A and B, a satisfactory bone reparation and bony union was noted within 12 weeks. In Groups C and D, bone reparation was not satisfied compared with Group A in terms of ostogenetic quantity and biomechanics.

CONCLUSIONSGelatinized MSO-TBC is an ideal artificial active bone that overcomes TBC shortcomings of fragileness and smooth surface that is not eligible for seed cell's adhesion. It is promising to put into clinical use extensively.

Animals ; Biomass ; Bone Diseases ; diagnostic imaging ; pathology ; therapy ; Bone Marrow Cells ; cytology ; Bone Substitutes ; Ceramics ; Disease Models, Animal ; Female ; Gelatin ; Male ; Osteoblasts ; cytology ; transplantation ; Osteogenesis ; Rabbits ; Radiography ; Radius ; diagnostic imaging ; injuries ; pathology ; surgery ; Stromal Cells ; cytology ; transplantation ; Tissue Engineering ; methods ; Treatment Outcome

BACKGROUNDIt has been proved that sevoflurane postconditioning (SpostC) could protect the heart against myocardial ischemia/reperfusion injury, however, there has been few research focused on the electrophysiological effects of SpostC. The objective of the study was to investigate the effects of SpostC on action potential duration (APD) and L-type calcium current (I(Ca, L)) in isolated cardiomyocytes.

METHODSLangendorff perfused SD rat hearts were randomly assigned to one of the time control (TC), ischemia/reperfusion (I/R, 25 minutes of ischemia followed by 30 minutes of reperfusion), and SpostC (postconditioned with 3% sevoflurane) groups. At the end of reperfusion, epicardial myocytes were dissociated enzymatically for patch clamp studies.

RESULTSSevoflurane directly prolonged APD and decreased peak I(Ca, L) densities in epicardial myocytes of the TC group (P < 0.05). I/R injury shortened APD and decreased peak I(Ca, L) densities in epicardial myocytes of the I/R group (P < 0.05). SpostC prolonged APD and increased peak I(Ca, L) densities in epicardial myocytes exposed to I/R injury (P < 0.05). SpostC decreased intracellular reactive oxygen species (ROS) levels, reduced the incidence of ventricular tachycardia and ventricular fibrillation, and decreased reperfusion arrhythmia scores compared with the I/R group (all P < 0.05).

CONCLUSIONSSpostC attenuates APD shortening and I(Ca, L) suppression induced by I/R injury. The regulation of APD and I(Ca, L) by SpostC might be related with intracellular ROS modulation, which contributes to the alleviation of reperfusion ventricular arrhythmia.

Action Potentials ; drug effects ; Animals ; Calcium ; metabolism ; Electrocardiography ; Methyl Ethers ; therapeutic use ; Patch-Clamp Techniques ; Pericardium ; drug effects ; metabolism ; Rats ; Reactive Oxygen Species ; metabolism ; Reperfusion Injury ; drug therapy ; metabolism