Docetaxel does not impair skeletal muscle force production in a murine model of cancer chemotherapy.

Chemotherapy drugs such as docetaxel are commonly used to treat cancer. Cancer patients treated with chemotherapy experience decreased physical fitness, muscle weakness and fatigue. To date, it is unclear whether these symptoms result only from cancer-derived factors or from the combination of cancer disease and cancer treatments, such as chemotherapy. In this study, we aimed at determining the impact of chemotherapy per se on force production of hind limb muscles from healthy mice treated with docetaxel. We hypothesized that docetaxel will decrease maximal force, exacerbate the force decline during repeated contractions and impair recovery after fatiguing stimulations. We examined the function of soleus and extensor digitorum longus (EDL) muscles 24 h and 72 h after a single injection of docetaxel (acute treatment), and 7 days after the third weekly injection of docetaxel (repeated treatment). Docetaxel was administrated by intravenous injection (20 mg/kg) in female FVB/NRj mice and control mice were injected with saline solution. Our results show that neither acute nor repeated docetaxel treatment significantly alters force production during maximal contractions, repeated contractions or recovery. Only a tendency to decreased peak specific force was observed in soleus muscles 24 h after a single injection of docetaxel (-17%, P = 0.13). In conclusion, docetaxel administered intravenously does not impair force production in hind limb muscles from healthy mice. It remains to be clarified whether docetaxel, or other chemotherapy drugs, affect muscle function in subjects with cancer and whether the side effects associated with chemotherapy (neurotoxicity, central fatigue, decreased physical activity, etc.) are responsible for the experienced muscle weakness and fatigue.