Amitriptyline hydrochloride (AMT), a tricyclic antidepressant, is known to exhibit antimicrobial effects against a wide range of bacterial species. This study aims to evaluate the effect of AMT on Brucella (B.) abortus infection in RAW 264.7 cells and ICR mice, which has not yet been clearly characterized. The results showed that all tested concentrations of AMT had no direct bactericidal effect on B. abortus survival at any incubation time point. Interestingly, RAW 264.7 cells pre-treated with a non-toxic high concentration of AMT before B. abortus infection showed a significant reduction in the phagocytosis of B. abortus at 20 min post-infection, compared to untreated cells. However, AMT treatment did not affect the intracellular replication of B. abortus compared to the control cells. Based on the reduced bacterial uptake observed in-vitro, an in-vivo experiment was conducted to assess whether daily oral administration of AMT at a dose of 20 mg/kg could inhibit B. abortus growth in ICR mice. The results showed that AMT treatment slightly increased both organ weights and bacterial loads, suggesting possible systemic effects of prolonged AMT exposure. In summary, these preliminary results provide initial insight into the potential effects of AMT on B. abortus infection both in-vitro and in-vivo. Therefore, further study should focus on dose optimization in-vivo and exploration of the underlying cellular mechanisms involved in AMT-mediated inhibition of phagocytosis during Brucella infection.

Abstract
INTRODUCTION
MATERIALS AND METHODS
    Amitriptyline hydrochloride preparation
    Cell culture and bacterial growth condition
    Cell viability assessment assay
    Bacterial internalization assay and intracellular growthassays
    Bactericidal assay
    Mice infection and treatment
    Statistical analysis
RESULTS
    Effect of AMT on RAW 264.7 cells viability andBrucella survivability
    Effect of AMT on internalization and intracellular growthof Brucella in RAW 264.7 cells
    Effect of AMT on Brucella infection in ICR mice
DISCUSSION
ACKNOWLEDGEMENTS
CONFLICT OF INTEREST STATEMENT
REFERENCES

• Tran Xuan Ngoc Huy(Institute of Animal Medicine, College of Veterinary Medicine, Gyeongsang National University, Jinju 52828, Korea)
• Trang Thi Nguyen(Institute of Animal Medicine, College of Veterinary Medicine, Gyeongsang National University, Jinju 52828, Korea)
• Said Abdi Salad(Institute of Animal Medicine, College of Veterinary Medicine, Gyeongsang National University, Jinju 52828, Korea)
• Ched Nicole Turbela Aguilar(Institute of Animal Medicine, College of Veterinary Medicine, Gyeongsang National University, Jinju 52828, Korea)
• Seong Eun Cho(Institute of Animal Medicine, College of Veterinary Medicine, Gyeongsang National University, Jinju 52828, Korea)
• WonGi Min(Institute of Animal Medicine, College of Veterinary Medicine, Gyeongsang National University, Jinju 52828, Korea)
• Hu Jang Lee(Institute of Animal Medicine, College of Veterinary Medicine, Gyeongsang National University, Jinju 52828, Korea)
• Suk Kim(Institute of Animal Medicine, College of Veterinary Medicine, Gyeongsang National University, Jinju 52828, Korea) Corresponding author
• Alisha Wehdnesday Bernardo Reyes(Department of Veterinary Paraclinical Sciences, College of Veterinary Medicine, University of the Philippines Los Baños, College, Laguna 4031, Philippines)