Evaluation of the healing of critical bone defects treated with nanogel scaffold, platelet-rich plasma and freeze dried bone allografs alone or in combination in the rabbit

Reconstruction of critical bone defects is one of the most important issues in medical science where the use of materials with properties osteoconduction, osteoinduction and osteogenic needs. In some studies, the posetive effect of platelet rich plasma and other studies have reported no effect on the healing of bone defects. Current study also aimed to assess the restoration of critical bone defects treated with platelet rich plasma, nanogel bone scaffold and allograft alone an in combination. In this experimental study, 50 adult New Zealand white rabbits were randomly divided in five groups. After general anesthesia, under sterile conditions to help trephin drill hole size 8×12 mm in the femor of lateral condyl each of the animals created. In control group (G1) the defect was filled by blood clot only. In G2, G3 and G4, inside cavity were replaced nanogel scaffold, nanogel scaffold+PRP and nanogel scaffold +PRP, +FDBA, respectively. At weeks 2, 4 and 8 after surgery, three animals from each group were randomly selected and then sampling of the defect, the bone repair techniques using histological and histomorphometric parameters. Data were analyzed by Kruskal-Wallis and Mann-Whitney U tests and p>0.05 was considered significant. The minimum amount of bone formation between groups was belonged to the control group. The mean bone parameters were significantly different in the second week (p<0.05) and the average of all bone parameters in the G1 and G2 were zero in this week. In the fourth week of the fourth group, mean resorption surface was (83.04±2.65) and mean bone volume was (81,83±4.60). The mean bone parameters were significantly different in the fourth week (p<0.05). In the eighth week of the fourth group, mean resoption surface was (81.61 ±1.81) and mean bone volume was (83.20±1.40). The mean bone parameters were significantly different in the eitghth week (p<0.05). The results of this study showed that the bone grafts combined with PRP compared with none combining them with PRP increases the healing rate of critical bone defects. Also, healing rate of bone defects using allograft is more than with nanogel scaffold. © Medwell Journals, 2016

Effects of pre-training injection of orexin A into dorsal raphe nucleus in passive avoidance acquisition on male rats

AbstractEndogenous orexins, especially orexin A, play an important role in spatial learning and memory. A recent study has shown the effect of orexinergic system in hippocampus on avoidance learning. Orexinergic receptors are distributed in dorsal raphe nucleus (DRN). The aim of this study was to evaluate the role of dorsal raphe orexinergic system in passive avoidance learning (PA). Rats were implanted with the cannula aimed at dorsal raphe nucleus. Orexin A or saline were injected into the DRN prior to avoidance training. Pre-training orexin type 1 receptors activation in DRN impaired passive avoidance acquisition but had no effect on PA retention

Comparison of the effect of three autogenous bone harvesting methods on cell viability in rabbits

Background. This study was designed to compare the viability of autogenous bone grafts, harvested using different methods, in order to determine the best harvesting technique with respect to more viable cells. Methods. In this animal experimental study, three harvesting methods, including manual instrument (chisel), rotary device and piezosurgery, were used for harvesting bone grafts from the lateral body of the mandible on the left and right sides of 10 rabbits. In each group, 20 bone samples were collected and their viability was assessed using MTS kit. Statistical analyses, including ANOVA and post hoc Tukey tests, were used for evaluating significant differences between the groups. Results. One-way ANOVA showed significant differences between all the groups (P=0.000). Data analysis using post hoc Tukey tests indicated that manual instrument and piezosurgery had no significant differences with regard to cell viability (P=0.749) and the cell viability in both groups was higher than that with the use of a rotary instrument (P=0.000). Conclusion. Autogenous bone grafts harvested with a manual instrument and piezosurgery had more viable cells in comparison to the bone chips harvested with a rotary device