The leading factor in tooth loss, periodontitis is a global public health concern. Common periodontal treatments include medication and mechanical therapy. Regarding the use of natural medicines to treat periodontitis, there has been much advancement. Cell proliferation, migration, differentiation, and homeostasis are modulated by tight junction (TJs). The present study reports the effectiveness of egg yolk oil (EYO) as a treatment for ligature-induced periodontitis by analyzing its microstructure and its effect on claudin-1. Eighteen mature male and female rats were used in the investigation, and they were categorized: Group 1 (Control Negative, n=9), which received no treatment; Group 2 (Control Positive, n=9), which received a silk ligature to cause periodontitis. The EYO treatment+ periodontitis for rats in Group 3 (EYO, n=9) was applied by ligature for 30 days. The incisor teeth with periodontal tissues were collected on days 7, 14, and 30 of the experiment and sections were prepared for both H&E staining and IHC for claudin-1 gene utilization. There was a significant improvement in alveolar bone loss, reduction in the inflammatory reaction, regeneration of PDL thickness, reduction of osteoclast numbers, and activation of claudin-1 tight junction expression compared to the control group in the entire experiment period. Our research concluded that EYO may have a critical role in alveolar bone formation with the regeneration of periodontal tissue damage that is associated with ligature-induced periodontitis via up-regulation of the expression of claudin-1 tight junction proteins that provide regeneration and repair processes, hence reducing pathological damages.