Objective To explore the significance of osteocyte apoptosis in steroidinduced osteonecrosis of the femoral head. Methods SixtyNew Zealand rabbits were divided into experimental group and control group(n=30). The experimental group was given 10 ml/kg of horse serum intravenously 2 times at 2 weeks intervals and an intraperitoneal injection of 45 ml/kg·d of methylprednisolone acetate for 3 days；the control group was given equal isotonic Na chloride. Osteocyteapoptosis was observe by means of TUNEL. Results The number of apoptosis in the experimental group(112.33‰±26.12‰) was significantly higher than that in the control(47.01‰±22.95‰) (Plt;0.01)in the 4th week. With time, osteocytes apoptosis progressively increased. In the 6thand 8th weeks, the percentage of empty osteocyte lacunae in the experimental group (17.23%±3.44%, 28.56%±3.45%) was significantly higher than that in the control group (11.29%±2.89%,11.26%±2.75%，Ｐlt;0.05). The transmission electron microscope showed that the characteristics of osteocyte apoptosisincluded intact nuclear membrane,comdensed chromatin and increased electron dense. Conclusion Osteocytes apoptosis may play a key role in the process of steroidinduced early osteonecrosis of the femoral head.
Objective To explore the expressions of bone morphogenetic protein 2 (BMP-2) and runt-related transcription facotr 2 (Runx2) and microarchitecture of trabecular bone periacetabula in adult patients with developmental dysplasia of the hip (DDH). Methods Between March and September 2008, the trabecular bone periacetabulum was collected from 8 patients with DDH who were scheduled for total hip arthroplasty (aged 37-55 years, 3 males and 5 females, trial group) and from 8 patients with avascular necrosis of the femoral head (Ficat stage II) who were scheduled for hip resurfacing arthroplasty (aged 36-55 years, 3 males and 5 females, control group). The expressions of BMP-2 and Runx2 in the trabecular bone were determined by real-time quantitative PCR, and the microarchitecture was observed by micro-CT and the following parameters were determined: bone volume/total volume (BV/TV), connectivity density (Conn.Dens), trabecular number (Tb. N), trabecular thickness (Tb.Th), trabecular separation (Tb.Sp), and structure model index (SMI). Results The expressions of BMP-2 and Runx2 were significantly lower in trial group than in control group (P lt; 0.05). The micro-CT showed sparse trabecular bone in trial group and dense trabecular bone in control group. BV/TV and Tb.N in trial group were significantly lower than those in control group, and SMI and Tb.Sp in trial group were significantly higher than those in control group (P lt; 0.05); there was no significant difference in Conn.Dens and Tb.Th between 2 groups (P gt; 0.05). Conclusion The trabecular bone is in a low metabolism condition and its microarchitecture is tendency to be osteoporosis trabecualr bone in adult patients with DDH. It may be related with the acetabular component loosening after total hip arthroplasty.
Objective To study the biological activity of recombinant adeno-associated virus vector (rAAV) coexpressing human vascular endothel ial growth factor165 (hVEGF165) and human bone morphogenetic protein 7 (hBMP-7) genes in vitro so as to provide a new method for the therapeutics of osteonecrosis. Methods The 3rd passage rabbit bone marrow mesenchymal stem cells (BMSCs) were transfected with rAAV-hVEGF165-internal ribosome entry site (IRES)-hBMP-7(experimental group) and green fluorescent protein (GFP) labeled rAAV-IRES-GFP (control group). The expressions ofhVEGF165 and hBMP-7 were detected by ELISA assay at the 1st, 2nd, 3rd, 7th, 14th days and Western blot assay at the14th day after transfection. The expression consistencies of hVEGF165 and hBMP-7 were observed by immunofluorescence assay at the 14th day after transfection. The biological activity of hVEGF165 was assessed by angiopoiesis experiment of the 3rd passage human umbil ical vein endothel ial cells (HUVEC). The biological activity of hBMP-7 was assessed by mineral ization of BMSCs detected by ALP staining and al izarin red staining. Results With infecting time, the hVEGF165 and hBMP-7 expressions increased gradually in two groups, showing significant difference between two groups (P lt; 0.05). The expressions of hVEGF165 and hBMP-7 were positive in experimental group and negative in control group, respectively. Immunofluorescence assay showed positive expressions of hVEGF165 and hBMP-7 in the exprimental group and negative expression in the control group, the expression of hVEGF165 and hBMP-7 had good consistencies. hVEGF165 secreted from BMSCs enhanced HUVEC migration, prol iferation and tube formation in experimental group. There was significant difference in the number of blood vessel between two groups (P lt; 0.05). The ALP staining showed more bly stained granules in experimental group than in control group. There was significant difference in the number of the mineral ized nodules between two groups (P lt; 0.05). Conclusion The rAAV-hVEGF165-IRES-hBMP-7 has good biological activity in vitro.