| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1997: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1996: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Research Abstract |
Osteoarthritis (OA) is characterized by marked formation of osteophytes, which are consisted of bone and cartilage. It is known that several growth factors are involved in chondrogenesis and osteogenesis. To investigate whether particular growth factors are expressed in osteophytes, we examined the expression of transforming growth factor-beta (TGF-beta) and basic fibroblast growth factor (bFGF) in the osteophytes from patients with OA.
Materials and methods) The osteophytes were obtained from 10 femoral head at the time of total hip arthroplasty in patients with OA.Total RNA was extracted with guanidine hydrochloride and pelleted by centrifugation on a cesium chloride cushion. Equal amount of total RNA was reverse-transcribed and polymerase chain reaction (PCR) was carried out using PCR primer sets for TGF-beta1, bFGF,and beta-actin. PCR products were electrophoresed on an agarose gel, and stained with ethidium bromide. beta-actin was co-amplified with particular growth factors. The am
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plified DNA fragments were quantified by examining the ethidium bromide fuluorescence on a personal computer with NIH Image software. The expression of growth factors were normalized to that of beta-actin. For comparison, cancellous bones were also obtained from 4 femoral heads with OA and 4 femoral heads with aseptic osteonecrosis, and they were processed as above. For immunohistochemical examinations, 4-mum sections of osteophytes were prepared after fixation with 10% formalin and decalcification. Streptavidin-Biotin method was performed using an anti-TGF-beta1 antibody.
Results) TGF-beta1 mRNA was expressed in all of the samples from osteophytes (100%), although the extent of the expression varies among the samples. In contrast, TGF-beta1 was not detected in any of the samples from aseptic osteonecrosis and 3 of 4 samples from the cancellous bone with OA.bFGF mRNA was expressed in all of 8 osteophytes (l00%) and 1 cancellous bone form femoral head, while it was not expressed in 2 samples from aseptic osteonecrosis. TGF-beta1 was detected in the cytoplasm of superficial cells in the cartilage of osteophytes by immunohistochemistry.
Discussion) We showed that TGF-beta1 mRNA and its protein were detected in osteophytes. TGF-beta1 and bFGF are reported to be regulators in differentiation and proliferation of bone and cartilage. Therefore, TGF-beta1 may be involved in bone and cartilage metabolism in osteophyte formation. Moreover, we observed the expression of bFGF mRNA in the osteophytes, suggesting that not only TGF-beta1 but also bFGF are involved in osteophyte formation. Less
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