RESUMO
Objective To investigate the effect of different pore sized hydroxyapatite for promoting bone vascularization in tissue engineering.Methods Male Wistar rats were randomly divided into three groups,named group A,B and C,which were im-planted hydroxyapatite bioceramics compositing 4 μg bone morphogenetic protein with different aperture of 200 -300,350 -450, 500-600 μm in the back subcutaneously.The size of each block was 5 mm×5 mm×1 mm in a weight about of 40.0 mg.After im-plantation,the animals were killed and the implants and the surrounding tissue were taken out at the first,second,third and forth week respectively.HE staining of histological analysis was used to detect the situation of local neovascularization.Results There was significant difference between second and third week in group A.Comparing the area of vascularization at different time points in group B and group C,there were significant difference in the comparison of intragroup (P <0.05 ).During the first week after surgery,there was only group C that had the area of vascularization.During the second and forth week after operation,the area of vascularization in group B and group C were significant higher than group A (P <0.05).The C group showed a great deal of new-born blood vessels and clear formation of bone trabeculae.Conclusion The hydroxyapatite bioceramics of 500-600 μm could better promote vascalarization of tissue engineering in bone.
RESUMO
Objective To explore the effect of diabetes mellitus (DM) on biological behavior of epidermal keratinocyte in rats. Methods A total of 40 Sprague-Dawley rats were randomized into control group and streptozotocin (STZ) -induced diabetes group. Of each group, 10 rats were implemented with deep partial-thickness scalding. The re-epithelialization rate was observed at the 3rd, 7th, 14th and 21th post-burn day. Histological characteristics and thickness of epidermal tissue in both groups were observed. The adhesion rate, cell cycles, apoptosis rate and migration ability of keratinocyte were measured. The accumulation of advanced glycosylation end products (AGEs) of epidermal tissue was observed. Results The percentages of re-epithelialized area at the 7th, 14th and 21th post-burn day were much lower in DM group than in control group (P<0.05). In DM group, the epidermal thickness was reduced obviously with obscure multilayered epithelium and less amount of prickle cells; The adhesion rates of 12, 24 h after culturing keratinocyte and the percentage of G2/M phase cells were lower in DM group than in control group (P<0.05). However, apoptosis rate of keratinocyte was higher, the amount of migration cell was significantly less in DM group than in control group (both P<0.05). There were lots of AGEs accumulated in epidermal tissue in DM group, while there were hardly AGEs in control group. Conclusions Re-epithelization blocked exists on non-healing wound in DM rats, which is related with the impaired keratinocyte biological behavior. A large of AGEs accumulate in the epidermal tissue of DM rats, which may be a important reason to inhibit keratinocyte function in diabetic environment.