Pilot study of bone tissue reparative regeneration of the young Trachemys scripta shell

Abstract

The turtles skeleton plan is an evolutionary developmental novelty in connection with the formation of a tortoise-specific carapacial ridge, which induces the growth of ribs in the dorsal direction and the subsequent formation of several carapace plates. The bone plates of these reptiles have different histogenesis: the neural and costal plates develop according to the mechanism of indirect osteogenesis by perichondral ossification of the axial skeleton elements (vertebrae and ribs), the peripheral and plastron bones develop according to the mechanism of direct osteogenesis in the dermis of the skin - these are the so-called «skin bones», which are derived from individual osteogenic cells outside the axial skeleton and develop by intramembranous osteogenesis. An experiment was carried out to study the post-traumatic osteogenesis of the carapace bone plates on a freshwater turtles Trachemys scripta at the age of 3 months. Two defects of carapace costal plates with a diameter of 4 mm and a depth to the fascia were performed with further routine histological examination. It was found that already on the 90th day the turtles carapace bones were restored with the formation of a full-fledged bone regenerate by the mechanism of indirect osteogenesis.