Nanopartículas de β-sitosterol associadas à laserterapia no tratamento de alopecia androgenética

Abstract

Hairs are of extreme relevance for men and women, both from the point of view of health and aesthetic. The main disease that occurs with decreased hair density is androgenetic alopecia (AGA), being heredity, the action of androgenic hormones and microinflammation factors involved in its pathophysiology. Given the limited number of therapeutic options to circumvent the signs and symptoms of AGA and the negative side effects associated with them, it is necessary to develop new strategies. This thesis reports a new therapeutic combination for the treatment of AGA, associating nanotechnology, a multifunctional active substance - β-sitosterol (BS) – and the lasertherapy. ΒS has anti-inflammatory and modulating properties of the enzyme 5-α-reductase (a key enzyme in the pathophysiology of AGA); nanoencapsulation may favor an increase in follicular penetration and prolonged release of substances, and the LLL has multiple benefits, such as stimulation of the local blood circulation and the production of ATP, anti-inflammatory and mitogenic effects. The effect of these nanostructures and the association with LLL was evaluated in vivo and in vitro. Nanocapsules (NC) and nanostructured lipid carriers (NLC) were prepared by the interfacial deposition method of preformed polymer and by emulsification followed by ultrasonication, respectively. Nanocarriers presented particle distribution exclusively in the nanometric range (111-132 nm for NLC; and 197-268 nm for NC) and low index of polydispersion. The zeta potential values were negative (~ -6.5 mV for NLC and – 9 mV for NC) and the pH slightly acidic (~ 6.1 and 6.7 for NC and NLC, respectively) for all formulations. BS content was close to the theoretical (1 mg/mL) for both nanoparticles. Irradiation of the nanoparticles with LLL 660 or 830 nm (4 J/cm2) did not induce changes in mean particle size, zeta potential and BS content. According to the HET-CAM assay data, the nanoformulations were not irritating, regardless of the presence of BS. Treatment of the 3T3 and HaCaT cell lines with the nanoparticles (with or without BS) did not induce cytotoxicity or cell proliferation, as well as the treatments associated with LLL. Cell viability decreased for both cell lines only when the BS solution was used, demonstrating the ability of nanostructures to protect against BS cytotoxicity. In the in vivo Allium cepa assay, the mitotic index was not influenced by the formulations, regardless of the presence of BS and its nanoencapsulation. The animal model of testosterone-induced AGA revealed through the histology that the effect of stimulation on hair growth is best when NC containing BS were associated with LLL. In conclusion, this thesis proposed, for the first time, the association of nanoparticles containing BS with LLL and this combination proved to be promising for the treatment of AGA.