Immunocytochemical Study of Amelogenin Deposition during the Early Odontogenesis of Molars in Alendronate-treated Newborn Rats

Abstract

S U M M A R Y Newborn rats were treated with sodium alendronate to study how enamel is formed and the effect of alendronate during early odontogenesis. Ultrastructural analysis combined with high-resolution immunocytochemistry for amelogenin was carried out. Twelve rats were subjected to daily SC injections of sodium alendronate (2.5 mg/kg/day) for 3 days on their dorsal region, whereas three rats were daily injected with saline solution as a control. Molar tooth germs from 3-day-old rats were fixed under microwave irradiation in 0.1% glutaraldehyde 1 4% formaldehyde buffered at pH 7.2 with 0.1 M sodium cacodylate. The specimens were left undecalcified, postfixed with osmium tetroxide, dehydrated, and embedded in LR White resin. Ultrathin sections were incubated with a chicken anti-24-kDa rat amelogenin antibody, a secondary antibody, and finally with a protein A-gold complex. Large patches of amelogenin were present over the unmineralized mantle dentin and at early secretory ameloblasts. At more advanced stages, they were also detected at the enamel matrix, as well as in the mineralized dentin, at the periodontoblastic space of the dentinal tubules, and at the predentin. It is likely that the main effect of alendronate at early stages of odontogenesis is the increase of synthesis/secretion of amelogenin, promoting its deposition within the forming dentin and enamel. (J Histochem Cytochem 54:713 -725, 2006)

Effects of alendronate on tooth eruption and molar root formation in young growing rats

“…Newborn Wistar albino rats (n=72) were used, of which 48 were subjected to daily subcutaneous injections of 2.5 mg/kg/ day sodium alendronate (Massa et al 2006) from the day of birth to 4, 14, and 30 days of age. An additional 24 rats were injected daily with sterile saline solution during the same period.…”

“…We used an experimental model in which a single dose (2.5 mg/kg/day) of sodium alendronate was administered daily to newborn rats (Massa et al 2006) from the day of birth until ages of up to 30 days. The aim was to observe the effects of this bisphosphonate on the development of molar teeth from the stages of root formation and eruption until the period in which the teeth should have reached the functional occlusal plane and their relationship with their surrounding bony crypt.…”

Effect of bisphosphonates sodium alendronate on shedding of deciduous molars in rabbits (histological and histochemical study)

“…This group is consisted of 20 rabbits, which were subjected to daily oral dose of 2.5 mg/kg of body wt./day sodium alendronate using oropharengeal tube [6] were divided into two subgroups:…”

Efeito do uso sistêmico de alendronato sódico no tecido ósseo e nas estruturas dentárias mineralizadas: estudo químico, mecânico e morfológico, em modelo murino

“…Dependendo da presença de um átomo de nitrogênio na cadeia alquílica da molécula, os BFs agem sendo tóxicos aos osteoclastos ou interferindo com vias intracelulares específicas no interior das células osteoclásticas (Massa et al, 2006 (Fleish, 2002;Massa et al, 2006;Russell, 2007;Ghoneima et al, 2010).…”

“…Segundo Massa et al (2006), o principal efeito do alendronato na estrutura dentária é romper o equilíbrio de secreção/degradação de amelogenina na matriz de esmalte, que é controlado pelos ameloblastos durante o estágio secretório da amelogênese. Embora os achados sugiram que as moléculas desta proteína tenham sido secretadas em excesso pelos ameloblastos, é possível que elas possam ter sido insuficientemente degradadas, durante o período secretório da amelogênese.…”