Actinotrichia are hyperpolymerized macrofibrils composed of a protein similar to collagen, denominated elastoidin (Becerra et al., 1983; Krukenberg, 1985).
Therefore, these two structures must be subject to different inhibition mechanisms during their synthesis kinetics, despite the similarity between elastoidin and collagen.
The actinotrichia are formed from hyperpolymerised macrofibrils of elastoidin, a protein with characteristics similar to those of collagen (Gross and Dumsha, 1958; Mari-Beffa et al., 1989).
Actinotrichia was initially observed around the fourth day after the excision of the fin (four days of regeneration), next to the connective tissue cells, similar to fibroblasts, indicating that probably they were the cells involved in the synthesis of elastoidin. They initiated their regeneration in the fin distal region, inside the connective tissue matrix, in adjacent position to the epidermis, laid in bilateral rows (Figure 5a).
Elastoidin: a two-component member of the collagen class.
Elastoidin turnover during tail fin regeneration in teleosts.
Actinotrichia are formed of hyperpolymerised macrofibrils of elastoidin, a protein with characteristics similar to those of collagen (Gross and Dumsha, 1958; Mari-Beffa et al., 1989).
Connective tissue cells, similar to fibroblasts, were observed near the regenerating actinotrichia, indicating that probably these are the cells involved in the synthesis of elastoidin. Cytoplasmic prolongations of these cells, partially surrounding the actinotrichia, could also be observed (see Figures 3 and 4).
The actinotrichia became increasingly thicker after 5, 6, 8, 10 and 12 days of regeneration, due to elastoidin synthesis, until they reached their normal size (see Figures 7, 8, 9 and 10).
Actinotrichia are synthesised distally and are maintained by a continuous turnover movement, which means that the regeneration of these structures can be described by the form of the synthesis and degradation of elastoidin, seen as a regulatory mechanism of the number and distribution of actinotrichia (Mari-Beffa et al., 1989).
Since there are controversies in the literature about the effect of naproxen in collagen synthesis and considering that the protein elastoidin presents similarities and differences to the protein collagen, our aim in this study was to verify if the same dose of naproxen already tested on the lepidotrichial collagen would not interfere with the synthesis of elastoidin during actinotrichia regeneration.