In vivo analysis of thrombus formation in arthritic mice

Abstract

Objectives

Rheumatoid arthritis (RA) is characterized by inflammation in multiple joints. In addition to causing joint destruction, the persistent systemic inflammation with RA increases the risk of cardiovascular disease. Although there are in vitro studies showing the prothrombotic effect of inflammatory cytokines, especially TNF, in vivo experimental evidence is lacking due to the complexity of in vivo modeling and observation. In this study, we aimed to model in vivo thrombus formation in arthritic mice and to determine whether the arthritic condition would further promote thrombotic formation.

Methods

Human TNF-transgenic mice were used as the arthritis model. Thrombus formation was observed on the testicular arterioles. Thrombus formation was induced by reactive oxygen species generated from hematoporphyrin under laser irradiation.

Results

Platelet thrombus formation was observed in real-time using a laser confocal microscopy in both wild-type and arthritic mice. Quantitative analyses revealed that no significant differences were observed in thrombus formation, represented by platelet attachment time and vascular obstruction time, in our experimental setting.

Conclusion

Although we confirmed the usefulness of this novel technique for in vivo studies, further investigation is required to conclude the possible mechanism of prothrombotic phenotypes under inflammatory conditions.

Keywords:

• Arthritis
• in vivo analysis
• inflammation
• platelet thrombosis

Acknowledgments

The authors thank Dr M. Ishii, Dr J. Kikuta (Department of Immunology and Cell Biology, Graduate School of Medicine and Frontier Biosciences, Osaka University, Osaka, Japan) for the instruction of in vivo imaging techniques. The authors are grateful to Dr K. Kawahara, Dr A. Nagasu, Dr S. Fujita, Dr T. Akagi, Y. Mino, H. Nakashima, N. Takemasa, M. Yoshimoto, N. Obara, A. Kusumoto (Department of Rheumatology, Kawasaki Medical School), and N. Konno (Graduate students, Kawasaki Medical School) for their technical assistance. The authors are also indebted to the staff at the Central Research Institute of Kawasaki Medical School. Additionally, The authors thank Editage for English language editing.

Conflict of interest

S. T., T. M., H. H., and Y. M. received scholarship donations from Chugai Pharmaceutical Company and AYUMI Pharmaceutical Corporation. The funders had no role in the design of the study, collection, analyses, or interpretation of data, writing of the manuscript, or in the decision to publish the results.

Additional information

Funding

This work was supported by a project research grant from Kawasaki Medical School [28B-032 to HH].