The impact of hypoestrogenism and occlusal function on MMP1, MMP8 and MMP13 expression in the odontogenic region in rats

Abstract

Background: The impact of estrogen deficiency and occlusion in the matrix metalloproteinases (MMPs) expression in dental tissues has not yet been elucidated. Objective: To evaluate the influence of estrogen deficiency and occlusal hypofunction and hyperfunction on the gene expression of MMP1, MMP8 and MMP13 in the odontogenic region of teeth in continuous growth, in the murine model. Material and methods: Rats (Wistar Hannover lineage) were divided into two groups according to the intervention received: Hypoestrogenism Group - ovariectomy surgery and Control Group - fictitious surgery. Occlusal hypofunction and hyperfunction conditions were also established in all animals (each animal presented both conditions). After euthanasia, the hemimandibles were removed to evaluate the gene expression through real time PCR. T-test was used to compare the mean differences between groups (P<0.05). Results: There was no statistically significant difference of the relative gene expression of MMP1, MMP8 and MMP13 between the hypoestrogenism and control groups (P>0.05). A statistically significant difference of the relative MMP13 expression between the occlusal hypofunction and hyperfunction tooth was observed (P=0.03). In the hypoestrogenism group, MMP13 was overexpressed in hypofunction tooth (P=0.045). Conclusion: Occlusal function affects MMP13 expression in the odontogenic region, in murine model.

Estrogen deficiency influences SEC23A gene expression in the odontogenic region of incisors – a murine model study

“…After euthanasia, the hemimandibles were removed and sectioned in the region of the condyle, coronoid process, and ramus of the mandible in order to isolate the odontogenic region of the lower incisor. The section of the hemimandible was performed with a 7011 double-sided diamond disc (KG Sorensen, Cotia, BR) with a thickness of 0.18 mm [2][3][4]. The mRNA samples from the odontogenic region were submitted to quantification of the gene expression of AMDHD1, CYP24A1, NADSYN1 and SEC23A.…”

“…Seventeen 21-day-old female Wistar rats were obtained from the animal facility of Ribeirão Preto, University of São Paulo, Brazil, were stored in the Bioterium II of the FORP/USP and housed in groups of two or three with circadian conditions of 12 hours, constant temperature and humidity (21 ± 1 °C and 55 to 75%, respectively) and ad libitum access to water and a standard diet for rodents (Labina Purina®/Agribrands do Brasil LTDA, Paulínia, São Paulo, Brazil). The animals were monitored throughout the pubertal period and were euthanized after 56 days of life [2][3][4].…”

“…Briefly, when the animals were 25 days old, they were anesthetized by intraperitoneal injection of 10% ketamine hydrochloride (55 mg/kg of gross body weight) and 2% xylazine hydrochloride (10 mg/kg of gross body weight). In the experimental group, the ovaries were removed bilaterally; while in the control group, a fictitious surgery was performed without removing or damaging the ovaries of the animals [2][3][4]. The success of the ovariectomy was confirmed by the gradual increase in the weight of the animals and uterine atrophy [2][3][4].…”

“…Estrogen is a steroid hormone present and active throughout an individual's life [1]. Although it is mainly responsible for female characteristics, it also important in the neuroendocrine, vascular, skeletal and immune systems of both sexes and dental development/tooth eruption [2][3][4]. Imbalances in serum estrogen levels can cause significant changes in body homeostasis.…”

“…Odontogenesis and tooth eruption process are strongly influenced by several local, systemic, environmental, genetic, and epigenetic factors [2][3][4]7,16]. There is some scientific evidence coming from studies in animal models showing that estrogen receptors are expressed in cells in the odontogenic region of teeth with continuous growth (incisors) [2][3][4]. There is also evidence demonstrating that vitamin D and its receptor are involved in tooth development [17].…”