Methodology in Wistar rats periodontitis induction: A modified ligation technique with injection of bacteria

Abstract

Introduction: Periodontitis is an inflammation affecting the supporting tissue of the teeth. It is characterized by periodontal ligament destruction and progressive alveolar bone loss. Periodontitis is often induced in laboratory animal models, such as Wistar rats used for experimental models. This study was conducted to develop a reproducible technique for induction of periodontitis in the mandible of Wistar rats using a modified ligation technique with an additional injection of Aggregatibacter actinomycetemcomitans. Context: Periodontitis is an inflammation affecting the supporting tissue of the teeth. It is characterized by periodontal ligament destruction and progressive alveolar bone loss. Aims: The aim of this study was to develop a reproducible technique for induction of periodontitis in the mandible of Wistar rats using a modified ligation technique with an additional injection of A. actinomycetemcomitans. Settings and Design: The study was conducted at LPPT Unit IV Universitas Gadjah Mada, Yogyakarta. Subjects and Methods: Ten 2-month-old male adult Wistar rats were used as experimental subjects with an average weight of 150–200 g. Nonresorbable silk ligature wire (4/0) was used as ligatures and placed with an “8”-shaped knot technique. The ligatures were placed in between both central incisors of the mandible for 7 days with additional injections of A. actinomycetemcomitans on the 1st day. The procedure was performed under ketamine anesthesia. After 7 days, ligatures were removed and the animal subjects were euthanized with cervical dislocation method and samples of mandibles were preserved in formalin solution and processed histologically and radiographically. Results: Modified induction technique of periodontitis with ligatures and additional injection of A. actinomycetemcomitans showed significant clinical inflammation, periodontal ligament widening, attachment loss, and alveolar bone loss. Conclusions: We demonstrated clinical, radiographic, and histological evaluation from this modified induction technique and concluded that it has several advantages: shorter period of induction time with more significant clinical changes and advanced bone loss, simplifying the technique for induction of periodontitis.