Comparative Morphology of Skeletal Development in Homo sapiens and Raja asterias: Divergent Stiffening Patterns Due to Different Matrix Calcification Processes
<p>Histology of the autopodial cartilage anlagen growth of <span class="html-italic">Homo sapiens</span> (hematoxylin–eosin, dec. sections). (<b>A</b>) Mitotic chondrocyte phase with dissolution of the nuclear membrane, doubling of the chromosomes and attachment to the spindle (prophase and metaphase). The red line shows the axis of the mitotic spindle. (<b>B</b>) Migration of the doubled chromosomes towards the spindle poles (anaphase). The red line shows the axis of the mitotic spindle. (<b>C</b>) Duplicated chondrocytes still in a single lacuna. The red line shows the axis of the duplicated chondrocytes. (<b>D</b>) Paired chondrocytes have formed their own lacunae, separated by matrix septa of increasing thickness. The red line shows the axis of the recently duplicated chondrocytes that have formed their own lacunae.</p> "> Figure 2
<p>Histology of the fetal autopodium of <span class="html-italic">Homo sapiens</span>. (<b>A</b>,<b>B</b>) (hematoxylin–eosin, dec. section) Form of the autopodium elements, with incipient mineral deposition in the middle sector of the metacarpals, not yet initiated in the short carpal bone anlagen and in the epiphyses. (<b>C</b>) (Alcian-blue, dec. section) Initial phase of mineral deposition with swelling of the chondrocytes (usually referred to as hypertrophy). At this stage, there are no signs of epiphyseal calcifying centers forming. (<b>D</b>) (Von Kossa-neutral red, un-dec. section) Mineral deposits in the cartilage matrix between the swollen chondrocytes and early mineral deposits in the periosteal bone envelope.</p> "> Figure 3
<p>Histology and primary calcified cartilage matrix resorption in <span class="html-italic">Homo sapiens</span> autopodium metacarpals. (<b>A</b>) (hematoxylin–eosin, dec. section) Swollen chondrocytes of the central anlage zone with matrix more densely stained by hematoxylin where mineral deposition occurs. Initial formation of the bone periosteal sleeve (red arrow). (<b>B</b>) (hematoxylin–eosin, dec. section) Vascular invasion and reabsorption of calcified cartilage matrix in the central zone of the anlage; the upper and lower sectors retain the denser colored matrix. Increased thickness of the bone periosteal sleeve (red arrow). (<b>C</b>) (hematoxylin–eosin, dec. section, bar = 100 μm) Advanced vascular invasion and calcified matrix resorption in the central zone of the anlage. (<b>D</b>) (Von Kossa neutral red, un-dec. section, bar = 100 μm) Residual calcified cartilage matrix of the central zone and first cortical bone layer of the diaphysis. (<b>E</b>) (hematoxylin–eosin, dec. section) Bone matrix (*) of the trabecula, resorbing two osteocytes, and a multinuclear osteoclast (black arrow) remodeling a metaphyseal trabecula.</p> "> Figure 4
<p>Histology of <span class="html-italic">R. asterias</span> pectoral fin radials. (<b>A</b>,<b>B</b>) (hematoxylin–eosin, dec. longitudinal section) High density of duplicating chondrocytes within a single lacuna and paired lacunae developing the radial (cylindrical) cartilage anlage. The matrix stained more intensely with hematoxylin corresponds to the zones of impendent mineral deposition that occur along the central axis of the radialis or in correspondence with the inter-radial amphiarthroses. Black arrows indicate the tegument. (<b>C</b>,<b>D</b>) (hematoxylin–eosin, dec., transverse section) Swellings of chondrocytes with densely stained matrix reproduce the histological features of mineral deposition of <span class="html-italic">H. sapiens</span> anlagen and show the non-remodeled texture of the calcified cartilaginous skeleton of chondrocytes (left section of figures). (*) the central cartilage core of the radials.</p> "> Figure 5
<p><span class="html-italic">Raja asterias</span> mature specimen of the inter-radial joint (toluidine blue, not declined/embedded in resin, longitudinal section). The joint consists of a layer of connective tissue (#) lying between the two discs (*) of calcified cartilage held by the branches of the central columns of the radialis. In the non-calcified cartilage matrix (weakly stained with toluidine), the tendency of the chondrocytes to align themselves into columns can be seen (arrows).</p> "> Figure 6
<p>Radiograph/morphometry of the central sector of the pectoral fin in dorso-ventral projection of an adult specimen of <span class="html-italic">R. asterias</span>. (<b>A</b>) The medial and lateral sectors are distinguished by the radials, whose two columns (superimposed in the dorso-ventral plane) run horizontally approximately halfway along the length of the fin. This diagram, reproduced from [<a href="#B6-animals-14-02575" class="html-bibr">6</a>], illustrates the irregular basal row of radial joints in the pterygium, highlighting some columns that are fused to the pterygium (*). The diagonally scaled rows of homologous radials (red line) reflect the curved profile of the entire fin margin and the gradual reduction in the number of radials in the anterior and posterior part of the fin. The symbol (^) indicates the centers of rotation of the two-column radials. (<b>B</b>) Graph showing the length (mean ± standard deviation) of the rows of radials 1–8 of the medial fin sector and 10–16 in the lateral sector; row 9 is the reference plane of the column turn in the horizontal plane. The dotted vertical line corresponds to the point of the radial sequence at which the two columns within the radial rotate in the horizontal plane.</p> "> Figure 7
<p>Transillumination and rotational dynamics of dorso-ventral columnar structures in <span class="html-italic">R. asterias</span>. Transillumination in dorso-ventral projection of the row plane, in which the dorso-ventral, superimposed columns rotate in the horizontal plane. The paired columns are held in the dorso-ventral position by the medial and lateral single discs (large arrowhead), while the lateral disc cleavage (small arrowheads) allows the columns to rotate within the visco-elastic muff of the non-calcified cartilage.</p> "> Figure 8
<p>Growth and mineral deposition in <span class="html-italic">R. asterias</span> pectoral fin radial, age group C. (<b>A</b>) Transilluminated, undecalcified specimen of the apical line of the pectoral fin rays. Mineral deposits in the form of small dark particles surround the aligned tesserae of the central column and the plates at the ends. The profile of the non-calcified cartilage cylinder is marked by red arrowheads, while the distalmost radial is still completely uncalcified. The apical fin consists of a bundle of keratin fibers between the dorsal and ventral tegument (blue arrow). (<b>B</b>) Transilluminated, undecalcified specimen of a radial in an advanced stage of calcification. The mineral deposits are compacted and form the aligned tiles of the central column with a tendency to fuse inwards. (<b>C</b>) Phase contrast image of B, confirming the pattern of the radial calcification process. (<b>D</b>) Transmitted light image, undecalcified specimen of the tiles at higher magnification. The mineral is deposited in the matrix around chondrocytes that are larger than those in the neighboring non-calcified matrix. (<b>E</b>) Phase contrast image of (<b>D</b>), showing the large chondrocytes embedded in the mineralized matrix.</p> "> Figure 9
<p>Heat-deproteinated radials of <span class="html-italic">R. asterias</span> pectoral fins of age group D (specimens 13 and 15). (<b>A</b>) Compacted mineral deposits outline the chained pattern of radial tiles in the center, but their shape is still irregular, as are the platelets at the ends. (<b>B</b>) More advanced mineralization with a regular, cylindrical shape of the tiles and plates. Regular distribution of lacunae in the calcified matrix of the plates. The dark bands separating the tiles correspond to carbon deposits of non-calcified cartilage burnt by heat treatment.</p> "> Figure 10
<p>Growth and ossification pattern of dolphin (<span class="html-italic">Tursipius truncatus</span>) fins (image reproduced from [<a href="#B7-animals-14-02575" class="html-bibr">7</a>]. (<b>A</b>) The stylopodium (1) and the two zeugopodium elements, radius (2) and ulna (3), show the ossified diaphyseal centers with flat epiphyseal ossification centers. The carpal bones, the metacarpals and the distal phalanges each have a single ossification center. White arrows indicate the distal metaphyseal growth plate cartilage of the humerus (1) and the proximal metaphyseal growth plate cartilage of the ulna (3). (<b>B</b>) The distal epiphyseal center has also developed in the radius and ulna, the proximal and distal epiphyseal centers in two metacarpals and only the proximal epiphyseal center in the first phalanges. The transverse radio-transparent lines between the diaphyseal and epiphyseal ossification centers correspond to the metaphyseal growth plate cartilage (as in terrestrial mammals) and regulate the longitudinal growth of the skeletal segment. White arrows indicate the distal metaphyseal cartilages of the radius (2) and ulna (3), as well as the proximal and distal cartilages of the 1st metacarpal. (<b>C</b>) Early fusion of the diaphyseal and epiphyseal ossification centers due to a halt in chondrocyte proliferation in the clefts of the metaphyseal growth plate. (<b>D</b>) Completed growth of the skeleton. The complete fusion of the metaphyseal cartilages indicates arrest of longitudinal growth. Comparison of the lateral and longitudinal diameter of metacarpals and phalanges indicates that the contribution of the metaphyseal plates of marine mammals to the longitudinal growth of the segment is smaller than in terrestrial mammals.</p> ">
Abstract
:Simple Summary
Abstract
1. Introduction
2. Materials and Methods
2.1. Ethics Statement
2.2. Source of the Material
- Homo sapiens Embryonic and Fetal Stages: Data were derived from Streeter’s illustration [9] based on autopsy material from the Carnegie Institution of Washington.
- Leucoraya ocellata Embryonic and Fetal Stages: Data were taken from the illustrations by Maxwell et al. [10].
- Histological slides of Human Fetal Limb Skeletal Segments were taken from the Archive of Morbid Anatomy (Spedali Civili di Brescia), where all pregnancy terminations between the 16th and 22nd week of gestation were routinely examined and archived (corresponding to Streeter stages 22–23). The selection of slides used in the present study was based on initial prenatal ultrasound diagnosis to exclude skeletal malformations. Two previous studies using the same histological material have been published [3,4] with the study protocol approved by DSMC Ethic Committee of the Brescia University (171.3/7 May 2015).
- Raja asterias juvenile specimens: Twelve juvenile specimens (Table 1) were provided by Aquarium of Livorno (Italy). These specimens were born from internally fertilized eggs, which were anchored in shallow corners. After oviposition from the capsule (from September 2022), the juveniles were reared in seawater in an indoor fishpond at a temperature of 18 °C. Embryonic development (not documented in this study) lasted 2–6 months [16]. The approximate age of the examined juveniles was 2 months (specimen 1); 3–5 months (specimens 2–8); and over 6 months (specimens 9–12). Overnight dead specimens were collected in the morning and immediately fixed in a 10% buffered formaldehyde solution. Older R. asterias specimens (specimens 13–15) were collected during a scientific campaign conducted by ARPAT team (U.O. Risorsa Ittica e Biodiversità Marina, Livorno) in the waters of Tuscany (Northwestern Mediterranean Sea) and fixed in formaldehyde solution within 24 h from capture.
- Data on marine mammals’ pectoral fin (flipper) skeletal development were derived from published radiographic film images of bottlenose dolphin (Tursiops truncatus) pectoral flipper bone maturation stages from [7] for comparison with the ossification pattern of human upper limb skeletal system.
2.3. Selection and Processing of Human Specimens
2.4. Processing of R. asterias Specimens
2.5. Raja asterias Pectoral Fin Radiograph Morphometry
3. Results
3.1. Early Cartilage Anlagen Development
3.2. Human Fetal Upper Limb Histology
3.3. Raja asterias Fin Development and Columnar Patterns
3.4. Comparison with Marine Mammals
4. Discussion
5. Conclusions
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Acknowledgments
Conflicts of Interest
References
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No. | Group | Sex | Weight (g) | Pectoral Fins Width (cm) (*) | Total Length (cm) |
---|---|---|---|---|---|
1 | A | n.a. | 1.20 | 4.0 | 7.6 |
2 | B | n.a. | 2.10 | 5.0 | 8.2 |
3 | B | n.a. | 2.20 | 5.5 | 9.2 |
4 | B | n.a. | 2.80 | 6.0 | 9.6 |
5 | B | n.a. | 2.95 | 6.3 | 9.7 |
6 | B | n.a. | 3.10 | 6.3 | 9.9 |
7 | B | n.a. | 3.25 | 6.5 | n.a. |
8 | B | n.a. | 4.30 | 7.6 | 10.8 |
9 | C | F | 8.50 | 9.9 | 12.7 |
10 | C | M | 9.70 | 10.8 | 14.6 |
11 | C | F | 9.90 | 11.7 | 16.3 |
12 | C | F | 10.50 | 12.5 | 16.9 |
13 | D | M | 260.0 | 19.0 | 25.0 |
14 | D | M | 350.0 | 27.5 | 40.0 |
15 | D | M | 769.0 | 34.0 | 52.5 |
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Pazzaglia, U.E.; Zecca, P.A.; Terova, G.; Serena, F.; Mancusi, C.; Raimondi, G.; Zarattini, G.; Raspanti, M.; Reguzzoni, M. Comparative Morphology of Skeletal Development in Homo sapiens and Raja asterias: Divergent Stiffening Patterns Due to Different Matrix Calcification Processes. Animals 2024, 14, 2575. https://doi.org/10.3390/ani14172575
Pazzaglia UE, Zecca PA, Terova G, Serena F, Mancusi C, Raimondi G, Zarattini G, Raspanti M, Reguzzoni M. Comparative Morphology of Skeletal Development in Homo sapiens and Raja asterias: Divergent Stiffening Patterns Due to Different Matrix Calcification Processes. Animals. 2024; 14(17):2575. https://doi.org/10.3390/ani14172575
Chicago/Turabian StylePazzaglia, Ugo E., Piero A. Zecca, Genciana Terova, Fabrizio Serena, Cecilia Mancusi, Giovanni Raimondi, Guido Zarattini, Mario Raspanti, and Marcella Reguzzoni. 2024. "Comparative Morphology of Skeletal Development in Homo sapiens and Raja asterias: Divergent Stiffening Patterns Due to Different Matrix Calcification Processes" Animals 14, no. 17: 2575. https://doi.org/10.3390/ani14172575