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objectivesTo explore the therapeutic mechanism of

methodsMale BALB/c mice bearing subcutaneous colorectal cancer CT26 cell xenografts were randomized into control group, model group, and treatment group. The mice in model and treatment groups were given intraperitoneal 5-FU injections every 3 days and treated with daily gavage of saline and QFG for 21 days, respectively; the mice in the control group and normally fed mice were given only saline gavage. Gripping test and hanging test of the mice were performed before and after the treatment, and on day 21, tumor weight and gastrocnemius muscle weight were measured, and histopathology and cell apoptosis in the gastrocnemius muscle were examined with HE staining, transmission electron microscopy and TUNEL assay. ATP content in the muscle was measured, and protein expressions of AMPK, PGC-1α, Cyt c, AIF, Apaf-1, Smac, Bcl-2, Bax, cleaved caspase-3 and cleaved caspase-9 were determined with immunohistochemistry.

resultsThe tumor-bearing mice in the control group showed significantly decreased gastrocnemius muscle weight and grip and suspension test scores. The gastrocnemius muscle showed ultrastructure injuries with lowered ATP content, obvious cell apoptosis, decreased expressions of AMPK, PGC-1 α, and Bcl-2, and increased expressions of Bax, Cyto C, AIF, Apaf-1, Smac, cleaved caspase-3 and cleaved caspase-9. These changes were obviously worsened in 5-FU-treated mice, while QFG treatment significantly increased gastrocnemius muscle weight and strength, ameliorated its ultrastructural injuries, reduced cell apoptosis, and reversed the abnormal protein expressions.

conclusionsQFG alleviates 5-FU-induced skeletal muscle fatigue in tumor-bearing mice by activating the AMPK/PGC-1α pathway and inhibiting mitochondria-dependent apoptosis in the gastrocnemius muscle.