The present study aimed to investigate the possible mitigating effect of L-carnitine (LC) and/or α-tocopherol (Vit. E) administration against tilmicosin (TIL)-induced cardiotoxicity in rats. Fifty-six male albino rats were divided into seven groups according to LC, Vit. E, and/or TIL administration. Control, LC, and Vit. E groups were given saline, 150 mg LC/kg body weight (BW)/day and 100 mg Vit. E/kg BW/day, respectively, orally once daily for 15 days. The TIL group was administered saline orally once daily for 15 days and a single dose of TIL (75 mg/kg BW) subcutaneously (SC) on day 14 from the starting of the experimental period (15 days). The TIL-LC, TIL-Vit. E, and TIL-LC-Vit. E groups received 150 mg LC/kg BW/day, 100 mg Vit. E/kg BW/day, and 150 mg LC/kg BW pulse 100 mg Vit. E/kg BW, respectively, orally once daily for 15 days with TIL as described above. The results revealed that the administration of TIL significantly (P ≤ 0.05) raised serum activities of heart injury indicators, lactate dehydrogenase (LDH), creatine kinase (CK), and CK-MB with substantial increase (P ≤ 0.05) in the cardiac contents of malondialdehyde (MDA) and decreased in antioxidants. The pathological changes appeared in the form of necrotic muscle fibers and massive inflammatory cellular infiltrations in the cardiac muscle and increased the caspase-3 immunohistochemical expression in the heart tissues as well. These changes were ameliorated by LC and/or Vit. E administration. In conclusion, supplementation of LC and/or Vit. E ameliorated the cardiotoxicity of the TIL SC injection in the rat.
Keywords: Antioxidants; Heart; L-Carnitine; Oxidative stress; Tilmicosin; Vitamin E.