1991 Fiscal Year Final Research Report Summary
Cryo-scanning electron microscopic study on mechanical and structural characteristics of the superficial zone of the articular cartilage
| Project/Area Number |
02670652
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Orthopaedic surgery
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| Research Institution | Shinshu University |
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Principal Investigator |
FUJIOKA Fumio Shinshu University, School of Medicine, Assistant, 医学部附属病院(整形外科), 助手 (00209024)
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| Co-Investigator(Kenkyū-buntansha) |
KINOSHITA Hisatoshi Shinshu University, School of Medicine, Assistant, 医学部(整形外科), 助手 (30177894)
KOBAYASHI Seneki Shinshu University, School of Medicine, Assistant, 医学部附属病院(整形外科), 助手 (40205464)
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| Project Period (FY) |
1990 – 1991
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| Keywords | Cryo-scanning electron microscope / Articular cartilage / Lamina splendens / Histrology / Ultrastructure / Joint / Biomechanics / Enzymatic digestion |
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| Research Abstract |
The first zone of the articular cartilage observed in previous studies with conventional scanning electron microscopes was found in the present study with a cryo-scanning electron microscope to consist of two layers, which were the superficial tangential zone (STZ) composed of collagen fibrils running parallel to the articular surface and an amorphous layer overlying the STZ. This layer on the STZ was addressed as the uppermost amorphous layer (UAL) in this study. In observation of the articular cartilage loaded by indentation, displacement of the STZ and the transitional and radial zones under an indenter was correlated both with pressure under an indenter and with indentation period. In the area adjacent to the indenter, the UAL was swollen, and its maximum thickness was correlated not with indentation period but with given pressure. As for topographical variation of morphology of the STE, the STZ in the meniscus-covered tibial cartilage was thicker than those in the femoral cartilage and in the meniscus-uncovered tibial cartilage. Various appearances of the UAL were classified into four types. Thickness of the UAL did not vary topographically but was correlated with these four types of appearances. Morphology of the UAL was influenced by dehydration, mechanical load, ionic state. Materials composing the UAL were digested by hyaluronidase but were resistant to collagenase. Collagen fibrils in the STZ were digested by collagenase. The UAL was found to protect the underlying zones from digestion by exogenous collagenase to some extent. Therefore, this layer might have some significance in initiation mechanisms of degenerative and inflammatory arthritis. Scraping on the surface of the articular cartilage removed the UAL resulting in impairment of lubrication of animal joints. During joint surgeries, the articular surface should not be scraped carelessly to avoid injuring this UAL.
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