Objective To explore a practical method of culturing discs organ system by observing the changes of the nucleus pulposus after the whole intervertebral discs (including cartilage end-plate, nucleus pulposus, and annulus fibrous)were cultivated. Methods A total of 335 intervertebral discs were taken out completely from 60 healthy SD rats (about150 g) aged 5-6 weeks of clear grade and rinsed by high osmotic sal ine solution containing heparin, then put to the culture plate after being divided into 5 groups randomly. The whole intervertebral discs were cultured with high osmotic (410 mOsmol/ kg) culture medium and changed the medium once every day, then the cell viabil ity (n=15), HE staining (n=15), Safranin O staining (n=15), and immunohistochemistry staining (n=2) were observed at 0, 3, 7, 14, and 21 days; RT-PCR result (n=5) was observed at 0, 3, 7, and 14 days. Results The cell viabil ity was not changed significantly within 14 days (P gt; 0.05) and was significantly lower at 21 days than at other time points (P lt; 0.01). The immunohistochemistry staining results for collagen type II were positive in nucleus pulposus cells at every time point. HE staining showed that the tissue integrity and morphology of the whole intervertebral discs were not changed within 14 days. Safranin O staining showed no significant difference in the matrix grey scale within 14 days (P gt; 0.05) and significant differences between 21 days and 0-14 days (P lt; 0.05). RT-PCR results showed that the mRNA expression of collagen type I increased with time, but the expressions of collagen type II, aggrecan, and decorin decreased, showing significant differences in the mRNA expressions of the matrix protein at each time point (P lt; 0.05). Conclusion High osmotic sal ine solution containing heparin could be used to cultivate the whole intervertebral discs, it is an ideal model for futher studies on physiology and pathology of intervertebral discs.
ObjectiveTo investigate the femoral bone remodeling and long-term effectiveness of total hip arthroplasty (THA) with anatomic medullary locking (AML) prosthesis.MethodsThe clinical data of 24 cases (26 hips) who were treated with THA with AML prosthesis between November 1997 and January 2003 were retrospectively analyzed. There were 12 males and 12 females with an age of 32-69 years (mean, 53.7 years). There were 5 cases (5 hips) of avascular necrosis of the femoral head, 6 cases (7 hips) of secondary osteoarthritis of the hip dysplasia, 6 cases (6 hips) of femoral neck fracture, 2 cases (2 hips) of primary osteoarthritis, 3 cases (3 hips) of revision surgery, 1 case (2 hips) of ankylosing spondylitis, 1 case (1 hip) of femoral head fracture. The patients were followed up at immediate, 6 weeks, 3 months, 6 months, 1 year, and then every year after operation for imaging evaluation (X-ray film was taken immediately after operation to evaluate the femoral isthmus compression, Engh standard was used to evaluate the biological fixation of the femoral shaft prosthesis, and Brooker method was used to evaluate the occurrence of heterotopic ossification); bone reconstruction evaluation [reconstruction of prosthesis and bone interface (type of bone reaction, Gruen zone, incidence, and occurrence time were recorded), reconstruction of bone around prosthesis (proximal femur stress shielding bone absorption was evaluated according to Engh and Bobyn methods, and bone mineral density change rate was measured)]; clinical efficacy evaluation [Harris score for efficacy, visual analogue scale (VAS) score for thigh pain].ResultsAll patients were followed up 15 years and 2 months to 20 years and 4 months, with a median of 16 years and 6 months. At immediate after operation, 24 hips (92.3%) had good femoral isthums compression, 24 hips (92.3%) had good bone ingrowth. Heterotopic ossification occurred in 2 patients with degree 1, 2 patients with degree 2, and 1 patient with degree 3 at 3-6 months after operation. Hyperplastic bone reactions were more common in Gruen 2, 3, 4, 5, 6, 10, 11, and 12 zones, mainly occurring at 6-20 months after operation, with the incidence of 3.8%-69.2%, with the highest incidence of spot welding. All absorptive bone reactions were osteolysis, which was common in Gruen 1 and 7 zones, and mainly occurred at 8 years after operation, with an incidence of 42.3%. No clear line (area) or enlarged sign of medullary cavity was observed. Twenty-one hips (80.8%) had 1 degree stress shieding, and 5 hips (19.2%) had 2 degree stress shieding. It mainly occurred at 10-24 months after operation in Gruen 1 and 7 zones. Dual energy X-ray absorptiometry showed that bone mineral density mainly decreased in Gruen 1, 2, 6, and 7 zones, mainly increased in Gruen 3, 4, and 5 zones. Bone mineral density loss progressed slowly after 2 years of operation, and it was stable in 5-8 years, but decreased rapidly in 8-9 years, and stabilized after 10 years. The Harris score increased from 51.1±6.2 before operation to 88.3±5.1 at last follow-up (t=–21.774, P=0.000). Mild thigh pain occurred in only 2 cases (7.7%) with the VAS score of 2. No aseptic loosening or revision of femoral prosthesis occurred during the follow-up.ConclusionThe application of AML prosthesis in THA has a good bone remodeling and a good long-term effectiveness.