No abstract

The expressions of matrix metalloproteinases 2 and 9 have been described during the development, as an example in heart and tooth but not in the small intestine yet. In this context, this study aimed to evaluate the expressions of MMP-2 and MMP-9 in the small intestine of Wistar rats during intrauterine (IU) and postnatal (PN) life. Expressions were determined on the 15th and 18th days of IU life and the 3rd, 10th, 17th, 25th, and 32nd days of PN life. Intestinal samples obtained from six animals were submitted to zymography, immunohistochemistry, and staining with Masson's trichrome. The results showed that MMP-2 and MMP-9 were not expressed during IU life; however, after birth, MMP-9 was immunolocalized in the goblet and mast cells. In conclusion, our results showed that MMP-2 and MMP-9 were not expressed in absorptive epithelial cells during the IU period of the small intestine but after birth, MMP-9 was expressed in the goblet cells, and mast cells present in the lamina propria.

Background: Obesity is a degenerative disease, causing several metabolic disturbances in different systems of the body. However, the effects of obesity on the development of mineralized tissues have not been well explored. Objectives: The aim of this study was to investigate the effects of hypothalamic obesity, induced by monosodium glutamate (MSG) on morphometric parameters in the tibia, hemimandible and incisor tooth in rats, as well as on the mineral content in the tibia, enamel and dentine. Materials and Methods: Twelve male Wistar rats were separated in a Control and experimental groups (MSG). The Control group received a daily subcutaneous injection of saline solution, while MSG group received the dose of 4 g/kg of body weight, on the five first days after birth. On the 90 th day, all rats were dead to be evaluated the Lee Index (LI), retroperitoneal fat deposit, the bone weight, density, volume, morphometric and mineral content. Results: In the MSG group the LI, retroperitoneal fat deposits and bone density were significantly increased while the bone weight, volume, and morphometric parameters were significantly decreased. The percentage of phosphorus was reduced and calcium was increased in the MSG group. Conclusion: In the obesity induced by MSG the mineral bone content is altered and produced significant changes in the somatometric parameters in the rat hemimandible, tibia and incisor.

Background: Calvaria skin has a reduced thickness, and its initial damage produced by irradiation was scarcely reported. We aimed to identify the initial effects of x-ray irradiation in the rat calvaria skin. Methods: After approval by the Animal Ethical Committee, calvaria skin sections of five Wistar rats per time point were evaluated on days 4, 9, 14, and 25 following a single 15-Gy x-ray irradiation of the head. The control group was composed of five rats and evaluated on day 4. Sections were assessed using hematoxylin-eosin and Masson's trichrome staining for morphology, inflammation, and fibrosis. Fibrosis was also evaluated by the collagen maturation index from Picrosirius red staining and by cell proliferation using the immunohistochemistry, after 5bromo-2-deoxyuridine intraperitoneal injection. Results: In irradiated rats, we observed a reduction in epithelial cell proliferation (p = 0.004) and in matrix metalloproteinase-9 expression (p < 0.001), an increase in the maturation index, and with a predominance in the type I collagen fibers, on days 9 and 14 (1.19 and 1.17, respectively). A progressive disorganization in the morphology of the collagen fibers at all time points and changes in morphology of the sebaceous gland cells and hair follicle were present until day 14. Conclusions: The initial damage produced by a single 15-Gy x-ray irradiation to the rat calvaria skin was a change in the normal morphology of collagen fibers to an amorphous aspect, a temporary absence of the sebaceous gland and hair follicles, and without a visible inflammatory process, cell proliferation, or fibrosis process in the dermis.

MMP-2 and MMP-9 are proteins with well stablished roles on the remodeling of tissue during morphogenesis. This study aimed to evaluate the activity and expression of the MMP-2 and MMP-9 in the rat small intestine mucosa layer on 15 th and 18 th days of intratuterine life (i.u.) and at 3rd, 10 th , 17 th, 25 th , and 32 th days after birth (a.b.). Samples were submitted to zimography, immunohistochemistry methods and Masson trichrome staining. Results showed that MMP-2 and MMP-9 were not expressed in the small intestine epithelium during intrauterine life.MMP-9 was immunolocalized in the villi goblet cells and in the lamina propria in cells identified as being the mast cells (a.b.). We concluded that in the i.u. and a.b. life the MMP-2 and MMP-9 were not expressed in the small intestine epithelium. However, after birth, because MMP-9 was expressed in the mast cels present in the lamina propria it may be involved in the remodeling process of the innate immunity that occurs during the small intestine development.key words: rat small intestine, MMP-2, MMP-9, development, mast cells During the suckling and weaning phases, the intestinal epithelium becomes completely developed, and two compartments can be identified; the villi (functional compartment) and the crypts, which are considered the proliferative compartment where cells are produced and differentiated, before their migration to the villi to execute their digestive functions.The suckling phase represents the period from birth until the 16th day of life, where milk is the main food. Around the 17th day, during the third week of life, diet with milk is changed to diet with solid food (weaning phase). Therefore, during the first three weeks after birth, the mucosa layer , specially the epithelium, goes through several morphological and physiological remodeling related to digestive and absorptive processes. These functional changes are produced by a shift in the expression of different enzymes present in the cell membrane like lactase, maltase, sucrase and intestinal alkaline phosphatase (Goldstein et al, 1971; Uezato and Fujita, 1983;Tojyo, 1984; Gomes et al., 2016).However, in this decade it has been demonstrated that another kind of enzymes denominated matrix metalloproteinases seem to have important roles during the development, growth and morphological maturation of different parts of the body like bones (Holmbeck et al, 1999; Yang et al., 2008), vascular system, skeletal muscle (Oh et al., 2004s), kidney and dental structures (Gomes et al., 2010, 2011, Omar et al., 2011, 2017.Metalloproteinases found in the extracellular matrix are denominated matrix metalloproteinases (MMPs) such as MMP-2 and MMP-9 (also denominated gelatinases) or may be anchored in the cell membrane which is denominated membrane matrix metalloproteinase (MT-MMPs). Despite this, there are still few descriptions about the involvement of MMPs in this process concerning to the development of the small intestine (Kurakata et al., 2008; Camargo et al., 2016) and none report regarding ex...