84
2.2 Conclusions
Cartilaginous skeleton in chondrichthyan fi shes is an example of the structural element
of great signifi cance for better understanding of the vertebrate evolution today.
The diversity, biochemistry, structure of the cartilage and the formation of both nonmineralized and mineralized cartilages have been studied extensively in lampreys,
hagfi sh, different chondrichthyes, and in marine mammals. It is proposed that the
jawless agnathans contain the core features of cellular cartilage development which
are conserved in the most basal extant vertebrates. Thus, according to Cattell et al.
( 2011 ), “the branchial basket cartilage of the agnathan lamprey possesses all of the
diagnostic histological and biochemical properties of gnathostome cellular cartilage;
including stack-of- coins and polygonal morphology, alcian-blue reactivity and
fi brillar collagen expression,” (Cattell et al. 2011 ). The cartilaginous skeleton of
chondrichthyan fi sh represents just one of their unique alternatives to body design
and adaptation, which evolved in ways that differ from other fi sh.
Chondrogenesis is the complex biochemical process that initiates during embryogenesis in the vertebrates. It leads to production of cartilage due the condensation of
initially loosely arranged mesenchymal cells into compact aggregates. This is followed by assumption of chondrocyte fate through the action of corresponding transcription factors related to the SOX family and bone morphogenetic factor (BMP)
intercellular signals (Glimm et al. 2012 ). Once differentiated, chondrocytes initiate
synthesis and secretion of a specialized extracellular matrix. Calcifi cation in higher
vertebrates is initiated by the cartilage elements produced in the embryonic stage,
within days through chondrocyte death and subsequent colonization of the natural
cartilage scaffold with bone producing cells known as osteoblasts.
Nowadays, the mechanical properties of soft and hard cartilage can be successfully determined such high precision methods as compression, indentation, tension,
and shear tests. These properties are necessary for any analysis of stress in the tissue;
as well as for better understanding of such phenomena as swimming, diving and
locomotion of marine vertebrates as one of the basic groups of animals for bioinspiration and biomimetics. The procedures include biological observation, kinematics
modeling, mechanism design, prototype implementation, and initial experiments.
From experimental and theoretical standpoints, the development of the diverse
bioinspired cartilage-based models would be the most intensively studied subjects
for biological materials science and biomedicine in the future .
References
Ahmed TA, Hincke MT (2010) Strategies for articular cartilage lesion repair and functional restoration. Tissue Eng B Rev 16(3):305–329
Applegate SP (1967) A survey of shark hard parts. In: Gilbert PW, Mathewson RF, Rall DP (eds)
Sharks, skates and rays. The Johns Hopkins Press, Baltimore
Bargahi A, Rabbani–Chadegani A (2008) Angiogenic inhibitor protein fractions derived from
shark cartilage. Biosci Rep 28:15–21
2 Cartilage of Marine Vertebrates
2.2 Conclusions
Cartilaginous skeleton in chondrichthyan fi shes is an example of the structural element
of great signifi cance for better understanding of the vertebrate evolution today.
The diversity, biochemistry, structure of the cartilage and the formation of both nonmineralized and mineralized cartilages have been studied extensively in lampreys,
hagfi sh, different chondrichthyes, and in marine mammals. It is proposed that the
jawless agnathans contain the core features of cellular cartilage development which
are conserved in the most basal extant vertebrates. Thus, according to Cattell et al.
( 2011 ), “the branchial basket cartilage of the agnathan lamprey possesses all of the
diagnostic histological and biochemical properties of gnathostome cellular cartilage;
including stack-of- coins and polygonal morphology, alcian-blue reactivity and
fi brillar collagen expression,” (Cattell et al. 2011 ). The cartilaginous skeleton of
chondrichthyan fi sh represents just one of their unique alternatives to body design
and adaptation, which evolved in ways that differ from other fi sh.
Chondrogenesis is the complex biochemical process that initiates during embryogenesis in the vertebrates. It leads to production of cartilage due the condensation of
initially loosely arranged mesenchymal cells into compact aggregates. This is followed by assumption of chondrocyte fate through the action of corresponding transcription factors related to the SOX family and bone morphogenetic factor (BMP)
intercellular signals (Glimm et al. 2012 ). Once differentiated, chondrocytes initiate
synthesis and secretion of a specialized extracellular matrix. Calcifi cation in higher
vertebrates is initiated by the cartilage elements produced in the embryonic stage,
within days through chondrocyte death and subsequent colonization of the natural
cartilage scaffold with bone producing cells known as osteoblasts.
Nowadays, the mechanical properties of soft and hard cartilage can be successfully determined such high precision methods as compression, indentation, tension,
and shear tests. These properties are necessary for any analysis of stress in the tissue;
as well as for better understanding of such phenomena as swimming, diving and
locomotion of marine vertebrates as one of the basic groups of animals for bioinspiration and biomimetics. The procedures include biological observation, kinematics
modeling, mechanism design, prototype implementation, and initial experiments.
From experimental and theoretical standpoints, the development of the diverse
bioinspired cartilage-based models would be the most intensively studied subjects
for biological materials science and biomedicine in the future .
References
Ahmed TA, Hincke MT (2010) Strategies for articular cartilage lesion repair and functional restoration. Tissue Eng B Rev 16(3):305–329
Applegate SP (1967) A survey of shark hard parts. In: Gilbert PW, Mathewson RF, Rall DP (eds)
Sharks, skates and rays. The Johns Hopkins Press, Baltimore
Bargahi A, Rabbani–Chadegani A (2008) Angiogenic inhibitor protein fractions derived from
shark cartilage. Biosci Rep 28:15–21
2 Cartilage of Marine Vertebrates