Effect of repeated desipramine and fluoxetine administration on post-adjuvant arthritis

The effects of desipramine and fluoxetine on the swelling of hind paws, radiologically-detectable bone destruction of hind paws, increase in spleen and popliteal lymph node weight, increase in metabolic activity of splenocytes and increase in proliferative activity of splenocytes and popliteal lymph node cells from right adjuvant injected paw in male C57BL/6 mice were studied on the 17th day after induction of post-adjuvant arthritis. Drugs were administered once-daily ip at a dose of 10 mg/kg. Fourteen days of desipramine administration, starting on the third day after injection of the adjuvant, significantly increased edema and radiologically assessed bone destruction, spleen and popliteal lymph node weight whereas fluoxetine induced an opposite effect, but it did not reduce edema in comparison with saline-treated control. Two-week desipramine administration significantly increased metabolic activity of splenocytes and proliferative activity of popliteal lymph node cells from the right adjuvant-injected paw, whereas 14 days of fluoxetine injection reduced proliferative activity of splenocytes in comparison with the saline-treated mice. Desipramine administration 30 days before and 17 days after adjuvant injection did not change these parameters in spite of reduction of proliferative activity of splenocytes. These findings indicate that: 1) fluoxetine has a suppressive effect on some of the local and systemic changes which occur in adjuvant-induced arthritis in mice, 2) two-week desipramine administration significantly increases whereas 47-day desipramine treatment does not change most of local and systemic parameters of post-adjuvant disease in C57BL/6 mice, 3) the action of fluoxetine differs from that of desipramine in this model of autoimmunodisease probably as a result of the distinct effect of these two drugs on corticoids levels and on the activity of a sympathetic nervous system.