Biological Optimization of Cortical Bone Allografts: A Study on the Effects of Mesenchymal Stem Cells and Partial Demineralization and Laser Perforation

Background: Despite promising results have shown by osteogenic cell-based demineralized bone matrix composites, they need to be optimized for grafts that act as structural frameworks in load-bearing defects. The purpose of this experiment is to determine the effect of bone marrow mesenchymal stem cells seeding on partially demineralized laser-perforated (DLP) structural allografts that have been implanted in critical femoral defects.Methods: Thirty-two Wistar rats were divided into four groups according to the type of structural bone allograft; the first: partially demineralized only (Donly), the second: partially demineralized stem cell seeded (DST), the third: partially DLP, and the fourth: partially demineralized laser-perforated and stem cell seeded (DLPST). Trans-cortical holes were achieved in four rows of three holes approximated cylindrical holes 0.5 mm in diameter, with centers 2.5 mm apart. P3 mesenchymal stromal cells (MSCs) were used for graft seeding. Histologic and histomorphometric analysis was performed at 12 weeks.Results: DLP grafts had the highest woven bone formation, where most parts of laser pores were completely healed by woven bone. DST and DLPST grafts surfaces had extra vessel-ingrowth-like porosities. Furthermore, in the DLPST grafts, a distinct bone formation at the interfaces was noted.Conclusions:This study indicated that surface changes induced by laser perforation, accelerated angiogenesis induction by MSCs, which resulted in endochondral bone formation at the interface. Despite non-optimal results, stem cells showed a tendency to improve osteochondrogenesis, and the process might have improved if they could have been supplemented with the proper stipulations

The Effects of the Preconception Endurance Exercise Training and Voluntary Exercise Activity during Pregnancy in C57BL/6 Mice on Lipid Profile of the Adult Offsprings

Abstract Background: The aim of this study was to determine the effect of preconception endurance exercise training with voluntary exercise activity during pregnancy in mother mice on lipid profile in adult offsprings. Materials and Methods: Twenty four C57BL/6 female mice were randomly divided into four subgroups: trained in preconception period and exercised during pregnancy (TE)(20.3±1.02g); trained in preconception periods but unexercised during pregnancy (TC)(21.58±0.4g); untrained in preconception periods but exercised during pregnancy (CE)(21.02±0.23g); untrained and unexercised (CC)(19.23±0.45g). Trained mice were subjected to a protocol of moderate endurance exercise training over a period of 4 weeks for 5 days before pregnancy. The fasting blood samples were collected from adult mice(8 weeks old) and serum levels of glucose and lipid profile were measured. Data were analyzed using two way ANOVA and Tukey’s post hoc test. Results: The Glucose test results in offspring showed that there was a significant interaction between group and sex and group main effect (p<0.001) Glucose levels of male offspring were significantly lower in TC and TE groups. Results on LDL also showed that the sex main effect was significant (p<0.001), and LDL levels of male born to TE and TC dams lower than in female offspring. Conclusion: Improving the mother's physical fitness by providing regular endurance training in the preconception period and maintaining it by exercise activty throughout pregnancy may have potential for eliciting positive changes in lipid profile of offspring, specially males