299
“Each fi n ray is formed by two apposed contralateral hemirays. A hemiray may
autonomously regenerate and segmentate in a position-independent manner. This is
observed when heterotopically grafted into an interray space, after amputation following extirpation of the contralateral hemiray or when simply ablated. During this
process, a proliferating hemiblastema is formed. This hemiblastema shows a pattern
of gene expression for a domain similar to half ray blastema. It was suggested
that there are contralateral interactions between hemiblastema of each ray, and that
hemiblastema may vary its morphogenesis, always differentiating as their host
region. These non-autonomous, position-dependent interactions control coordinated
bifurcations, segment joints, and ray length independently,” (Murciano et al. 2007 ).
Fin regeneration is, probably, dependent on the hedgehog and bone morphogenetic signaling pathways. It was shown, for example, that the hedgehog signalling
pathway is involved in both growth of the fi n regenerate, and formation and patterning
of the dermal bones composing the fi n rays (Avaron et al. 2006 ). Also Bone
Morphogenic Protein signalling is required for both the growth of the regenerate,
and for the differentiation of the bone-secreting cells (Smith et al. 2006 ).
While much progress has been made in regeneration research based on such
model organisms as zebrafi sh and medaka, other fi sh species also seem to be very
appropriate for these studies. For example, the plesiomorphic and derived characters
found in Polypteriformes make these fish attractive subjects for performing
evolutionary and developmental comparisons. In the recently published work
(Cuervo et al. 2012 ), the authors evaluated the ability of the Polypterus fi n to regenerate upon a quasi-complete amputation. They observed that Polypterus regenerates
its fi ns with remarkable accuracy, only comparable to the regeneration observed
in amphibian urodeles. Thus, “pluridisciplinary approaches led to the notion that fi n
regeneration is an intricate phenomenon involving epithelial-mesenchymal and
reciprocal exchanges throughout the process, as well as interactions between ray
and interray tissue,” (Akimenko et al. 2003 ).
I suggest that progress in fi sh fi n cell culture research might be important for studies on regeneration as well as on tissue engineering. However, medically important
topic is still in its infancy. Development of cell lines from both freshwater and marine
fi sh for both identifying the pathogenesis and for vaccine production in case of viral
diseases, is well known imperative, and seems to be of commercial importance
(Lakra et al. 2010 ; Han et al. 2011 ). According Mauger et al. ( 2006 ), “it is essential
to recover the somatic cells from the fi sh body without sacrifi cing the animal, and fi n
explants are good candidates for this purpose. They are easy to sample and they have
natural regenerative capacities. This prevents long-term disabling of the fi sh and it
should provide a good proliferation of cells from the fi n in a culture system,” (Mauger
et al. 2006 ; see also Akimenko et al. 2003 ; Prasanna et al. 2000 ).
Several papers have described methods for fi n cells culture, mostly of freshwater
fi sh (Mothersill et al. 1995 ) (Fig. 7.10 ), mostly to study a karyotype of the cells
( Esox lucius , Carassius auratus , Apogon imberbis , and Sparus aurata Alvarez et al.
1991 ; Wang et al. 2003 ), as well as a cell proliferation and ageing ( C. auratus ;
Shima et al. 1980 ). Selected cells cultured from fi n explants of medaka ( Oryzias
latipes ) and bighead carp ( Aristichthys nobilis ) were showed to be useful for cloning
7.4 Fin Regeneration and Fin Cell Culture
“Each fi n ray is formed by two apposed contralateral hemirays. A hemiray may
autonomously regenerate and segmentate in a position-independent manner. This is
observed when heterotopically grafted into an interray space, after amputation following extirpation of the contralateral hemiray or when simply ablated. During this
process, a proliferating hemiblastema is formed. This hemiblastema shows a pattern
of gene expression for a domain similar to half ray blastema. It was suggested
that there are contralateral interactions between hemiblastema of each ray, and that
hemiblastema may vary its morphogenesis, always differentiating as their host
region. These non-autonomous, position-dependent interactions control coordinated
bifurcations, segment joints, and ray length independently,” (Murciano et al. 2007 ).
Fin regeneration is, probably, dependent on the hedgehog and bone morphogenetic signaling pathways. It was shown, for example, that the hedgehog signalling
pathway is involved in both growth of the fi n regenerate, and formation and patterning
of the dermal bones composing the fi n rays (Avaron et al. 2006 ). Also Bone
Morphogenic Protein signalling is required for both the growth of the regenerate,
and for the differentiation of the bone-secreting cells (Smith et al. 2006 ).
While much progress has been made in regeneration research based on such
model organisms as zebrafi sh and medaka, other fi sh species also seem to be very
appropriate for these studies. For example, the plesiomorphic and derived characters
found in Polypteriformes make these fish attractive subjects for performing
evolutionary and developmental comparisons. In the recently published work
(Cuervo et al. 2012 ), the authors evaluated the ability of the Polypterus fi n to regenerate upon a quasi-complete amputation. They observed that Polypterus regenerates
its fi ns with remarkable accuracy, only comparable to the regeneration observed
in amphibian urodeles. Thus, “pluridisciplinary approaches led to the notion that fi n
regeneration is an intricate phenomenon involving epithelial-mesenchymal and
reciprocal exchanges throughout the process, as well as interactions between ray
and interray tissue,” (Akimenko et al. 2003 ).
I suggest that progress in fi sh fi n cell culture research might be important for studies on regeneration as well as on tissue engineering. However, medically important
topic is still in its infancy. Development of cell lines from both freshwater and marine
fi sh for both identifying the pathogenesis and for vaccine production in case of viral
diseases, is well known imperative, and seems to be of commercial importance
(Lakra et al. 2010 ; Han et al. 2011 ). According Mauger et al. ( 2006 ), “it is essential
to recover the somatic cells from the fi sh body without sacrifi cing the animal, and fi n
explants are good candidates for this purpose. They are easy to sample and they have
natural regenerative capacities. This prevents long-term disabling of the fi sh and it
should provide a good proliferation of cells from the fi n in a culture system,” (Mauger
et al. 2006 ; see also Akimenko et al. 2003 ; Prasanna et al. 2000 ).
Several papers have described methods for fi n cells culture, mostly of freshwater
fi sh (Mothersill et al. 1995 ) (Fig. 7.10 ), mostly to study a karyotype of the cells
( Esox lucius , Carassius auratus , Apogon imberbis , and Sparus aurata Alvarez et al.
1991 ; Wang et al. 2003 ), as well as a cell proliferation and ageing ( C. auratus ;
Shima et al. 1980 ). Selected cells cultured from fi n explants of medaka ( Oryzias
latipes ) and bighead carp ( Aristichthys nobilis ) were showed to be useful for cloning
7.4 Fin Regeneration and Fin Cell Culture