Objective · To investigate the effect of cisplatin on heart failure in bladder cancer miceimpairing granulocytic myeloid-derived suppressor cells (G-MDSCs). Methods · Fifty 8-week-old specific pathogen free (SPF) C3H/He healthy female mice were used to establish the bladder cancer model after subcutaneous injection of MBT-2 mice bladder cancer cells. The mice were divided into group A–E, 10 mice in each group, and the group A was set as the blank control group. The group B–E mice were continuously intraperitoneally injected with 5 mg/ (kg.d) isoproterenol for 14 d to successfully establish the heart failure model. The group B was set as the control group. The mice were intraperitoneally injected with 7.5 mg/kg cisplatin every 48 h for chemotherapy, and killed at 14 d in the group C. G-MDSCs were identified, isolated and purifiedflow cytometry. 1×107 purified G-MDSCs were intravenously injected into the group D mice via the tail vein every 7 d. The group E mice was treatedcombining the procedure of the group C and the group D. The myocardial tissue of the mice was stainedhematoxylin-eosin staining. And the heart failure degree of the mice was analyzedthe heart weight/body weight ratio and the observation under the inverted phase contrast microscope. Results · Flow cytometry results showed that compared with the group B, the level of G-MDSCs in the circulation system of the group C mice was significantly decreased (P0.000). Hematoxylin-eosin staining and Image J software analysis showed that compared with the group B, the heart weight/body weight ratio and the area of myocardial cells of the group C mice were significantly increased (P0.001, P0.002). However, after G-MDSCs injection, the above two indexes in the group D mice were decreased compared with those in the group B (P0.000, P0.011). After cisplatin/G-MDSCs combined treatment, the above two indexes in the group E were also decreased compared with those in the group C (P0.000, P0.001). Conclusion · G-MDSCs have cardioprotective effects, while cisplatin can facilitate heart failureimpairing G-MDSCs.