Efeito da nicotina na viabilidade e morfologia de fibroblastos: estudo in vitro

Abstract

The aim of this study was to evaluate, in vitro, the effect of nicotine on the viability and morphology of fibroblasts from a continuous lineage. Two experimental groups were prepared, with different drug dosages (0 - control, 10 microgram 100 microgram, 0.5 mg, 1 mg) and conditioning time (1 and 24 hours). Twelve-well microplates were utilized. Each well received 2 ml of fresh culture medium and 1 ml of a solution containing 1 x 10(5) cells/ml. Nicotine was then added to the wells, at the tested concentrations. After the incubation period, cell viability was assessed by means of 0.4% trypan blue staining. Cell viability and morphology were assessed in an inverted microscope, by a single examiner, who was blind as to the experimental groups. The experiment was repeated 5 times. Regarding morphology, in the 1-hour conditioned group there was statistically significant difference between the control group and the group with the greatest dose of nicotine. These differences were also observed between the control group and all nicotine groups after 24 hours. The results of the Kruskal-Wallis test revealed that more unviable cells were found in the groups exposed to nicotine, in comparison with the control group, both after 1 and 24 hours of conditioning (p < 0.05). Moreover, with increasing doses of nicotine there was a directly proportional increase in the number of unviable cells, both after 1 and 24 hours of exposure (p = 0.0053 and p = 0.00001, respectively). The conclusion of this study is that nicotine can alter, in vitro, the viability and morphology of fibroblasts in a manner proportional to the dose and time of exposure.

The influence of nicotine on the population of fibroblasts in cutaneous scars in rats

“…According to some of these authors, fibroblasts exposed to nicotine undergo morphological alterations, principally cytoplasmic vacuolization. They become inactive and even unviable [11][12][13]17 .…”

“…Several experimental studies have reported cytoplasmatic modifications, degeneration and inactivity of fibroblasts [11][12][13] , in addition to a reduced number of these cells and their differentiation 11,12,[14][15][16][17] and deficiencies in collagen synthesis 11,13,15,18,19 .…”

A influência da nicotina na densidade de colágeno em cicatrizes cutâneas, em ratos

“…Os fibroblastos sofreriam tanto na sua estrutura 15-17 quanto na proliferação e diferenciação 13,15,16,[18][19][20] . Nestes estudos estão descritas deficiências da síntese do colágeno 15,17,18,22,23 .…”

“…Fang e Svoboda, estudando fibroblastos humanos, cultivados com diferentes concentrações de nicotina, observaram que existia inibição da diferenciação dos fibroblastos a miofibroblastos e atribuíram a isto a diminuição da contração das feridas 14 . São relatadas modificações citoplasmáticas, degeneração e inatividade dos fibroblastos [15][16][17] , além da diminuição do número destas células e da sua diferenciação 13,15,16,[18][19][20] . Estes efeitos foram também descritos nos osteoblastos, afetando a reconstituição após fraturas 21 .…”

Análogos de micosporinas: síntese e avaliação de parâmetros farmacológicos e toxicológicos

“…Quando ocorre corrosão, a lesão pode tanto ser superficial, quanto estendida aos tecidos mais profundos, formando assim uma porta de entrada para aquelas substâncias que antes não conseguia permear o extrato, exercerem efeitos sistêmicos deletérios, ou mesmo causar seus efeitos diretamente sobre as células, a citotoxidade (Singh e Singh, 2001;Oga, 2008). (Martinez et al, 2002;Nathalie et al, 2006), porém inúmeras alterações a nível metabólico também ocorrem, decorrente do desequilíbrio homeostásico ou modificações no código genético celular, alterações que podem ser avaliadas por diversas metodologias analíticas (Mosmann, 1983;Rogers e McDougal, 2002;OECD, 2004;Nathalie et al, 2006;Valadares et al, 2007).…”