Gelatinolytic activity in salivary glands of 28- and 60-day-old rats exposed to lead and fluoride

• Grant number: 10/07169-2
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: July 01, 2010
• End date: June 30, 2011
• Field of knowledge: Biological Sciences - Biochemistry - Enzymology
• Principal Investigator: Raquel Fernanda Gerlach
• Grantee: Yanna Maria dos Reis Matos
• Host Institution: Faculdade de Odontologia de Ribeirão Preto (FORP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil

Abstract

The growth and differentiation of the salivary glands depends on the remodeling process, and remodeling depends on the tissue proteolytic activity, particularly the activity of matriz metaloproteinases (MMPs). Many recent studies point to the increased prevalence of caries associated with increased concentration of lead in the blood and cadmium in urine. These two heavy metals inhibit MMPs, and this suggests that they might have an effect on the salivary gland remodeling process via MMPs, affecting their function. The aim of this study is to quantify and compare the total gelatinolytic activity in submandibular salivary glands of 28- and 60-day-old male Wistar rats of 4 groups: control, F, Pb, and F+Pb. Female and male rats (250 g) will be randomly divided into the four groups prior to mating. The control group will receive water with low lead and low fluoride throughout the study, while the other groups will receive water containing 100 ppm of Fluoride (F), 30 ppm of lead (Pb), and water containing 100 ppm of fluoride plus 30 ppm of lead (F+Pb). Offspring will be maintained on the same water treatment until day 28 after birth, when 15 male rats will be killed and salivary glands will be collected. Salivary glands will be either homogenized or cut in a cryostat, and in situ zimography will be carried out using DQ gelatin. Values obtained for each group will be compared statistically, and a p<0.05 will be accepted as significant. This is a subproject (A) of a larger project composed of the following evaluations: A) Gelatinolytic activity, B) immunolocalization of MMP-2 and MMP-9 C) determination of the amounts of lead and fluoride in the different calcified tissues, whole blood and salivary glands. Subprojects B and C are projects will also be carried out by IC students, for whom we will try to obtain support from FAPESP. (AU)