The Synergistic Effect of Full-Spectrum Light Therapy and Transient Immunosuppressants Prolonged Allotransplant Survival.

BACKGROUND

The lifelong administration of immunosuppressants remains the largest drawback in vascularized composite allotransplantation (VCA). Therefore, developing alternative strategies to minimize the long-term use of immunosuppressive agents is crucial. This study investigated whether full-spectrum bright light therapy (FBLT) combined with short-term immunosuppressant therapy could prolong VCA survival in a rodent hindlimb model.

METHODS

Hindlimb allotransplantation was conducted from Brown-Norway to Lewis rats, and the rats were divided into 4 groups. Group 1 did not receive treatment as a rejection control. Group 2 received FBLT alone. Group 3 was treated with short-term antilymphocyte serum (ALS) and cyclosporine A (CsA). Group 4 was administered short-term ALS/CsA combined with FBLT for 8 weeks. Peripheral blood and transplanted tissues were collected for analysis.

RESULTS

The results revealed median survival time of FBLT alone (group 2) did not increase allograft survival compared with the control (group 1). However, in group 4, FBLT combined with short-term ALS/CsA, median composite tissue allograft survival time (266 days) was significantly prolonged compared with groups 1 (11 days), 2 (10 days), and 3 (41 days) ( P < 0.01). Group 4 also showed a significant increase in regulatory T cells ( P = 0.04) and transforming growth factor-β1 levels ( P = 0.02), and a trend toward a decrease in interleukin-1β levels ( P = 0.03) at 16 weeks after transplantation as compared with control (group 1).

CONCLUSIONS

FBLT combined with short-term immunosuppressants prolonged allotransplant survival by modulating T-cell regulatory functions and antiinflammatory cytokine expression. This approach could be a potential strategy to increase VCA survival.

CLINICAL RELEVANCE STATEMENT: Full-spectrum light therapy could be a potential strategy to increase vascularized composite allotransplant survival.