Amputated newt's limb regeneration under exposure to ultrasound and CaCl2

The aim of research is to establish the effect of the combined impact of ultrasound and CaCl2 on the macro- and microstructure of the regenerating tissues of newt 's thoracic limb after amputation. It was determined that after amputation of the thoracic limb, the newt undergoes a phased post-traumatic regeneration. The limb is fully restored by the 85th day and becomes physiologically, macro- and microstructurally equivalent to the original limb. When the regeneration is stimulated by the combined effect of ultrasound and CaCl2 added to the water, the process of limb recovery proceeds more intensively and ends 2-3 weeks earlier than in the control group. On the 42nd day after amputation, the length of the regenerating stump in the control group was 7.03 ± 0.11 mm, and in the second group, where ultrasound was used, it was longer than in the control, by 13.3 % (P ≤ 0.05 ) and reached 7.97 ± 0.11 mm. In the third group, combined exposure to ultrasound and CaCl2 for 10 days, exposition 30 s, the length of the stump exceeded the control value by 27.6 % (P ≤ 0.05) and reached 8.97 ± 0.18 mm. On the 42nd day, skin with keratinizing epithelium and glands, striated muscles and bones, represented by cartilaginous tissue, were formed at the microstructural level. At the same time, the most pronounced and completed processes of osteogenesis were noted in the group where the combined effect of ultrasound and CaCl2 was used. The bones of the newt 's thoracic limb after amputation are regenerated due to the cartilaginous tissue of the epiphyseal plates formed at the site of the mesenchyme. Cartilage tissue is represented by isogenic groups of rounded chondrocytes, the space between which is filled with a fibrous matrix - chondromucoid. Stimulation of regeneration by the combined effect of ultrasound and CaCl2 accelerates only the regeneration process, but retains the regularities of the development of cartilaginous bone in the zone of the epiphyseal plates from the mesenchyme.