Effects of nicotine administration in rats on MMP2 and VEGF levels in periodontal membrane

Background: Nicotine is associated with increased incidence of periodontal disease and poor response to therapy. This article aimed at identifying the expression of matrix metalloproteinases 2 (MMPs2) and vascular endothelial growth factor (VEGF) proteins on extracellular matrix, fibrous distribution and angiogenetic development in periodontitis caused by nicotine effects on periodontal membrane.Materials and methods: In this experimental study, rats were divided into nicotine and control groups. While the rats in the nicotine group (n = 6) were administered 2 mg/kg nicotine sulphate for 28 days, the animals in the control group (n = 6) were only administered 1.5 mL physiologic saline solution subcutaneously for 28 days.Results: Histological sections were prepared and immunohistochemically stained for MMP2 and VEGF. The sections stained with Trichrome-Masson were observed under light microscope. VEGF and MMP2 immunoreactivity of periodontal gingiva and dentin was assessed by immunohistochemical staining.Conclusions: Nicotine reduces MMP production, disrupts collagen synthesis and causes periodontitis. We observed that nicotine increases periodontitis by disrupting periodontal membrane and prevents tooth to anchor in dental alveoli by disrupting epithelial structure

Histological Changes to the Rat Mandibular Condyle in Response to Long-term Exposure to an Extremely Low Frequency Magnetic Field

Background: The need for electrical power continues to increase along with the rapidly growing economies of industrialized countries. However, the effects of electrical fields (EFs) on human health remain unclear. Hence, the aim of the present study is to evaluate the histological effects of an extremely low frequency magnetic field (ELF-MF) on the rat mandibular condyle. Methods: Twenty female Sprague-Dawley rats were randomly allocated to one of two groups (n = 10): an untreated control group and an ELF-MF group exposed to a 1.5-mT ELF-MF for 4 h per day for 6 months. After exposure, the left mandibular condyles of all rats were collected for histopathological examinations.  Results: The histopathological changes to the ELF-MF group included a non-homogenous appearance and decreased thickness of the hypertrophic layer, irregular appearances of bone marrow cavities, significant deterioration, and delayed calcification and ossification. There were no significant differences in the thicknesses or histomorphometric appearances of the fibrotic, proliferative, and hypertrophic layers of the mandibular condyle of rats between the groups (p = 0.05). Conclusion: Long-term ELF-MF exposure can induce histopathological changes to the mandibular condyle of rats