Kamikihito ameliorates tumor‐induced sickness behavior in mice

Abstract

ABSTRACTAimKamikihito (KKT), a Kampo medicine composed of 14 herbs, has been used clinically to treat psychiatric disorders such as anxiety, insomnia, amnesia and depression. Sickness behavior refers to a series of behavioral and psychological changes that occur due to cancer and inflammatory disease. The etiological mechanism is not known in detail, and thus there is no established standard therapy for sickness behavior. In this study, we examined the effects of KKT on tumor‐induced sickness behavior in mice, and compared the effects of KKT with those of milnacipran, a serotonin noradrenaline re‐uptake inhibitor.MethodsSeven‐week‐old male BALB/c mice were inoculated with the murine adenocarcinoma cell line colon 26. The effects of KKT on behavioral changes in the colon 26‐inoculated mice were evaluated on object exploration test, social interaction test and forced swim test.ResultsInoculation of colon 26 cells induced sickness behavior, such as loss of object exploration, social interaction deficits and immobility in the forced swim test without affecting spontaneous locomotor activity. KKT ameliorated these behavioral changes. Milnacipran reduced the loss of object exploration and immobility in the forced swim test, but not social interaction deficits. Both KKT and milnacipran did not affect tumor growth.Conclusion KKT may ameliorate emotional aspects of sickness behavior similarly to or better than milnacipran, and is a potential treatment for sickness behavior.