Background and aim: It has been previously shown that activated macrophages play an important role in defense mechanism by releasing nitric oxide (NO). It has also been reported that its release was affected by medical treatment. NO seems to be responsible for some side effects of cyclophosphamide. The aim of this study was to evaluate the effect of two drugs on NO release.
Methods: The mice were given different concentrations of cyclophosphamide daily up to five days. After 28 days, the mice were sacrificed and cellular suspension was collected and incubated for 48 hours. Then supernatant was collected and nitrite was measured by Griess method as an indicator of NO.
Results: The Results showed that cyclophosphamide at low concentration reduced NO release by peritoneal macrophages compared to that of the control group (48% ± 2, P<0.05). Cyclophosphamide at high concentration enhanced NO release 380% ± 5 compared to that of the control group (P<0.05). Hydrocortisone enhanced NO release (P<0.05) in-group that were subjected to low dose of cyclophosphamide. In-group that were subjected to a high dose of cyclophosphamide, hydrocortisone reduced NO release and the maximum reduction was 30.43% (P<0.05).
Conclusion: It seems that part of the immunosuppressive effect of cyclophosphamide might be due to reduction of NO release. Therefore, it is better to avoid giving corticosteroid to patients that are under cyclophosphamide treatment.