Influence of ovariectomy combined with lack of masticatory force in the evolution of periodontal disease

AIM: To evaluate the influence of ovariectomy combined with lack of masticatory force in the evolution of periodontal disease induced in rats. METHODS: Forty rats were bilaterally ovariectomized and 40 were submitted to sham ovariectomy. Periodontal disease was induced in the mandibular left first molar and the maxillary left first molar was extracted from half of the rats. The rats were randomly euthanized at 3, 7, 14 and 30 days post periodontal disease induction. Serial sections were obtained from the furcation area and stained for histological and histomorphometric analysis. The results of the histomorphometric analysis were statistically analyzed by ANOVA and Tukey tests. RESULTS: The results demonstrated statistically significant differences in the percentage of bone tissue when the variables presence or absence of estrogen (p=0.020) and time of euthanasia (p=0.002) were evaluated. However, the extraction procedure did not significantly affect the percentage of bone tissue (p=0.598). CONCLUSIONS : The bone loss resulting from periodontal disease is increased by estrogen deficiency and varies according to the time course of periodontitis. In contrast, masticatory force does not seem to interfere in bone loss derived from periodontal disease.

Influência da ovariectomia associada à dieta deficiente em cálcio na periodontite experimental / Influence of ovariectomy associated to dietary calcium deficiency on the experimental periodontitis

A deficiência de estrógeno e de cálcio na dieta são condições que potencialmente causam alterações no osso alveolar e como consequência podem agravar a doença periodontal. O objetivo deste estudo foi avaliar a influência da deficiência estrogênica, associada ou não à dieta deficiente em cálcio, sobre a perda óssea, a atividade de osteoclastos e os marcadores teciduais de remodelação óssea, na doença periodontal induzida em ratas. Foram utilizadas 96 ratas, aos 90 dias de idade, das quais 64 foram submetidas à ovariectomia e 32 à falsa-ovariectomia(Sham). Das 64 ratas ovariectomizadas, 32 receberam dieta comercial padrão (OVZ) e as outras receberam dieta deficiente em cálcio (OVZ’). Em todas as ratas, 60 dias após a cirurgia, foi induzida doença periodontal por meio da colocação de ligadura ao redor do primeiro molar inferior esquerdo. Com 3, 7, 14 e 30 dias após a inserção das ligaduras, efetuou-se a eutanásia. As hemi-mandíbulas esquerdas foram desmineralizadas e processadas para a obtenção de cortes microscópicos. Os cortes corados por H.E. foram analisados qualitativamente e quantitativamente por histomorfometria, utilizando-seplanimetria por contagem de pontos, com o auxilio do programa Image J.Foi realizada reação enzimoistoquímica para marcação da fosfatase ácidatartarato resistente (TRAP) e reação imunoistoquímica para marcação do receptor ativador de NF-kappa B (RANK), de seu ligante (RANKL) e de osteoprotegerina (OPG). Os dados obtidos foram analisados estatisticamente por meio do teste de Mann-Whitney. Os resultados mostraram que o grupo Sham apresentou maior quantidade de matriz óssea e menor quantidade de marcação de células TRAP+ comparado com o grupo OVZ. Entretanto, o grupo OVZ apresentou menor quantidade de matriz óssea e marcação similar de células TRAP+ comparado ao grupo OVZ’. Em relação aos marcadores de remodelação óssea, o grupo Sham apresentou maior índice de marcação para OPG e RANKL, porém, para RANK mostrou quantidade...

Estrogen and dietary calcium deficiencies are conditions that potentially lead to alveolar bone alterations and might consequently worsen periodontal disease. The aims of the present study were to evaluate estrogen deficiency associated or not to dietary calcium deficiency overbone loss and to evaluate the activity of osteoclasts and bone remodelingtissue markers on induced periodontal disease in rats. Ninety six rats aging 90 days were used in the present study, being 64 submitted to ovariectomy and 32 to sham-ovariectomy (Sham). Thirty-two rats from the ovariectomized group received standard diet (OVZ), while the rest received calcium deficient diet (OVZ’). Periodontal disease was induced 60 days after the surgery in all rats by placing a ligature surrounding the first mandibular left molar. Euthanasia was performed 3, 7, 14 and 30 days after ligature placement. Left hemi-mandibles were demineralized and processed for obtaining the microscopic slices. HE stained slices were qualitatively and quantitatively analyzed by histomorphometry using a point-counting planimetry, and the Image J software. Tartrate-resistant acid phosphatase (TRAP) was marked by enzyme histochemistry, while factor NF-Kappa B receptor activator (RANK), its ligand (RANKL) and osteoprotegerin (OPG) were marked by immunohistochemistry. Obtained data were submitted to statistical analysis by Mann-Whitney test. The results revealed that Sham group presented greater bone matrix quantity and lower TRAP+ cell in comparison to OVZ group. However, OVZ group presented lower bone matrix quantity and similar TRAP+ cells as OVZ’group. Regarding bone remodeling markers, Sham group presented the greatest marking index for OPG and RANKL, being the RANK quantity similar to OVZ group. The OVZ’ group presented higher marking indices for RANK and similar levels of OPG and RANKL in comparison to OVZ. It was concluded that greater bone loss, which is not accentuated by calcium deficient diet...