Mechanical role of actinotrichia in shaping the caudal fin of zebrafish

Fin ray branching is defined by TRAP+ osteolytic tubules

“…OLTs show a non-fluorescent lumen which suggests that they may be surrounding other structures, such as actinotrichia. In fact, actinotrichia have recently been sugested to have a role in ray bifurcation and in preventing ray fusion (Nakagawa et al, 2022). Another hypothesis is that OLTs are filled with a liquid substance, or possibly a reservoir of osteolytic enzymes, thus, explaining the accumulation of TRAP within the OLTs, as observed.…”

“…Apart from the outermost ones, all rays are bifurcated at different proximo-distal positions, according to the shape of the fin and ray length, i.e., shorter rays branching more proximally and longer rays more distally (Cardeira et al, 2016). The proximo-distal positioning of the bifurcations along the rays is critical for the overall fin architecture, as recently highlighted by studies of collagen9ac1c zebrafish mutants which display impaired bifurcation associated with fin misshaping (Nakagawa et al, 2022).…”

“…Importantly, among the signaling pathways controling bone patterning, such as during limb development (Capdevila and Belmonte, 2001; Riddle et al, 1993), Sonic hedgehog (Shh) has been described as a key factor controling ray bifurcation during fin regeneration (Armstrong et al, 2017; Laforest et al, 1998). However, repetitive amputations (Azevedo et al, 2012), macrophage activity (Petrie et al, 2014), actinotrichia organization (Nakagawa et al, 2022), and hydrodynamics (Dagenais et al, 2021) are able to alter the proximo-distal position of ray branchpoints through apparently Shh-independent mechanisms. Thus, the formation and shaping of bifurcated bony structures and the cellular contribution to these processes remain unclear.…”

The effect of different diclofenac doses on bone repairing and col1a1 gene expression in Poecilia latipinna (Lesueur, 1821)

“…In current study, it was observed that there are defection in the fins represented by obvious erosion, especially the caudal and pectoral fins, in addition to the occurrence of noticeable deformations in the dorsal fin bones for fish exposed to diclofenac, in males abnormalities in the gonopodium, was observed, these abnormalities included reduction number and size the rays that generate the gonopodium leading to a weakness in connective tissue ligaments subsequently affecting fertilization process. the generation of rays is related to the generation of collagen any defect in disrupting col9a1c gene leads to decrease the number of spines in the rays and fins gradually become shorter finally turn into abnormal shape and sometimes totally damage occurrence (Nakagawa et al, 2022). Phan et al, (2019) cited that capillaries are neatly arranged between the layers of basal keratinocytes and mesenchymal cells, and contain collagen (col1a1) and (col2a1).…”

Temporally and regionally distinct morphogenetic processes govern zebrafish tail fin blood vessel network expansion

“…While a vascular plexus is present at the tips of regenerating fin vessels, this plexus is either absent or greatly reduced in normal growing fins (Huang et al, 2009; Xu et al ., 2014), suggesting that distinct processes might pattern regenerating adult blood vessels in comparison to blood vessels in developing fish. The formation of this plexus further depends on structural features of the extracellular matrix, as interfering with collagen assembly results in plexus defects (Huang et al ., 2003; Huang et al ., 2009; Nakagawa et al, 2022; Senk and Djonov, 2021). A recent report showed that osteoblasts are required for normal fin blood vessel outgrowth (Bump et al, 2022).…”