The Effect of Fluoxetine and Ibuprofen on BCG-Induced Alteration in Pain Sensitivity in Mice

Clinical observations recognized the co-existence and interactions of pain and depression a long time, ago. The aim of this work was to study the effect of ibuprofen and fluoxetine on BCGinduced depressive-like behaviour, on formalin-induced pain, as well as on mechanical allodynia after planter incision in mice. BCG induced a depressive behaviour that was seen in the forced swim test (FST) and the tail suspension test (TST). It also induced a decrease in pain-related behaviour in the formalin test, and an increase in the baseline in mechanical allodynia test compared to the control group. Fluoxetine (80 mg/L of drinking water) showed a significant decrease in the immobility time in the FST and TST and enhanced pain related behaviour in formalin test in the BCG-inoculated group. However, it did not affect the increase in the pain threshold in the planter incision allodynia model. Adding ibuprofen to drinking water (0.2 g/L of drinking water), reversed the depressive like behaviour induced by BCG and enhanced pain-related behaviour in formalin test, in both the total pain-related behaviour and phase 2. It also prevented the increase in the base line induced by BCG. On the other hand, the incisional pain model was not affected by BCG inoculation except at the 2-hour time point, where it showed hypoalgesia, as well.