Diet-induced Generalized Periodontitis in Lewis Rats

Area of Science:

• Oral biology
• Immunology
• Animal models

Background:

• Periodontitis is a global public health issue.
• Rodents in the genus *Rattus* are resistant to spontaneous periodontitis, necessitating mechanical induction in research.
• Lewis rats exhibit heightened susceptibility to inflammatory diseases due to Th1 and Th17 immune responses.

Purpose of the Study:

• To investigate if a high-sucrose and casein (HSC) diet could induce periodontitis in Lewis rats without mechanical intervention.
• To characterize the oral microenvironment, inflammatory responses, and periodontal tissue changes associated with the HSC diet.
• To evaluate potential systemic effects of the HSC diet.

Main Methods:

• Lewis rats were fed standard or HSC diets from 6 to 29 weeks of age.
• Periodontitis severity was assessed via histology and micro-computed tomography (μCT) of maxillae and mandibles.
• Immunohistochemistry and gene expression analysis were used to evaluate inflammatory responses and cytokine profiles in periodontal tissues and liver.

Main Results:

• The HSC diet induced mild to moderate periodontitis in Lewis rats, characterized by inflammatory cell infiltration, osteoclast-mediated bone resorption, and gingival epithelial hyperplasia.
• A host Th1-immune response was observed in periodontal tissues.
• No significant metabolic abnormalities were detected in HSC-fed rats.

Conclusions:

• Feeding Lewis rats a diet high in sucrose and casein for 24 weeks successfully induced periodontitis without mechanical procedures.
• This HSC-fed Lewis rat model may serve as a valuable tool for studying mild to moderate periodontitis, mimicking aspects of the human condition.
• The model is useful for investigating periodontitis pathogenesis and therapeutic strategies without confounding mechanical interventions.