1999 Fiscal Year Final Research Report Summary
Pathological Study of Osteonecrosis in SHRs and WKYs -Associated with Structural and Mechanical Factors-
| Project/Area Number |
10671367
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Orthopaedic surgery
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| Research Institution | Nagasaki University |
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Principal Investigator |
SHINDO Hiroyuki Nagasaki University School of Medicine, Professor, 医学部, 教授 (30107677)
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| Co-Investigator(Kenkyū-buntansha) |
KUMAGAI Kenji Nagasaki University School of Medicine, Assistant Professor, 医学部, 助手 (00315235)
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| Project Period (FY) |
1998 – 1999
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| Keywords | Spontaneously Hypertensive Rat / Wister Kyoto Rat / Osteonecrosis / Femoral Epiphysis / Structural Strength / Mechanical Stress |
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| Research Abstract |
Osteonecrosis occurred frequently in the epiphyseal nuclei of the femoral head in SHRs and in the overloaded femoral head in WKYs during the growth period.
The osteonecrosis of the proxymal femoral epiphysis in growing rats resembles that in Perthes' disease. The purpose of this study was to compare the radiographic and histologic findings of osteonecrosis of the epiphyseal nucleus of the femoral head in SHRs and WKYs. Clarifying their differences could contribute not only to systematization of the relationships among the factors participating in its etiology but could also provide a clue to the pathogenesis of Perthes' disease. The SHRs were kept in ordinary cages and the WKYs in custom-made high cage from 5 weeks to almost 15 weeks after birth (various periods). The WKYs had to stand on their hind limbs to feed because the feed box and drinking aperture were place at high level. There was a relative high incidence of avascular in the epiphyseal nuclei of the femoral heads; 45.8% in SHRs and 33.3% in WKYs. The osteonecrosis in both SHRs and WKYs resulted from interruption of the feeding vessels in the Ranvier zone. In addition to the similar findings of osteonecrosis, there were, however, several differences in the pathological condition of the proxymal femur in the SHRs and WKYs. In SHRs, there were marked cartilage abnormalities in the lateral part of the femoral head, a high incidence of ossification disturbances of the proximal femurs, such as a flattened femoral head and a short neck. In WKYs, there are no such constitutional abnormalities which may induce cartilaginous disorders. The increased mechanical stress caused by standing seems to be a causative factor of osteonecrosis in WKYs. The study suggests that standing, which applies an overloads to the hip joint, is a causative factor in osteonecrosis of the femoral head in growing rats.
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