During the first period of 15 days, the rabbit biokinetics is appropriate to initiate a formation of young bone, which can be confirmed or not, at 30 days. In this animal model, the bone formation can be initiated before 15 days, as has been seen in other studies, but it is very spars. Moreover, the first days guide us towards an evolution of the bone response that is confirmed at 15 days. It has been published in previous works [10] that the fast periosteal response found could be explained by direct action of GH on the pluripotential mesenchymal cells in the first steps of the repair process. The GH accelerated this process in what has been called the “impulse effect” stimulating osteoblasts, chondroblasts, and fibroblasts. However, the most authors have not statistically found a response to GH dependent dose [10, 12], asseveration that is in accordance with our data.

Systemic and local administration of growth factors accelerates bone regeneration [36] and promotes osteoinductive effects [37]. In fact, the systemic administration of GH has shown to accelerate fracture healing [38] at longer periods of implantation. The beneficial role of GH on the bone regeneration could be achieved at initial local administration of GH in the implantation site where oxidized Ti6Al4V implant is located and after a critical period of implantation time, systemic administration by means of small regular dose, according to [38].