title: Role of levothyroxine and vitamin E supplementation in the treatment of oxidative stress-induced injury and apoptosis of myocardial cells in hypothyroid rats.
abstract: OBJECTIVE
  To explore the underlying mechanism and treatment of myocardial injury caused by hypothyroidism, we evaluated oxidative stress in serum and myocardial tissue of hypothyroid rats. The effect of levothyroxine (LT4) replacement therapy and vitamin E (VitE) supplementation on oxidative stress-induced injury and apoptosis of myocardial tissue is examined.
  
  
  METHODS
  Male Sprague-Dawley rats were divided into five groups: normal control group, propylthiouracil group (PTU group), LT4 treatment group (PTU + LT4 group), vitamin E treatment group (PTU + VitE group), and combined treatment group (PTU + LT4 + VitE group). Superoxide dismutase (SOD) activity and malondialdehyde (MDA) expression in serum and myocardium were determined. Myocardial apoptosis index (AI) in each group was determined by TUNEL assay.
  
  
  RESULTS
  SOD levels in serum were significantly increased in PTU + VitE and PTU + LT4 + Vit E groups, as compared to that in PTU and PTU + LT4 groups (P < 0.05). MDA levels in serum and myocardial tissue were significantly lower in PTU + LT4, PTU + VitE, and PTU + LT4 + VitE groups, as compared to that in the PTU group (P < 0.05). Myocardial apoptosis was significantly increased in PTU and PTU + VitE groups as compared to that in the normal control group (P < 0.05), while it was significantly lower in PTU + LT4 and PTU + LT4 + VitE groups, as compared to that in the PTU group (P < 0.05).
  
  
  CONCLUSIONS
  In this study, levothyroxine replacement therapy and vitamin E supplementation appeared to ameliorate myocardial apoptosis in hypothyroid rats, the mechanism of which appears to be related to improved thyroid function and reduced oxidative stress.
authors.affiliation: Department of Endorinology and Metabolism, The Second Hospital of Anhui Medical University, 678, Furong Road, Hefei, Anhui, 230601, China. jingluye@126.com.
authors.forename: J
authors.initials: J
authors.lastname: Ye
authors.affiliation: Department of Endorinology and Metabolism, The Second Hospital of Anhui Medical University, 678, Furong Road, Hefei, Anhui, 230601, China.
authors.forename: X
authors.initials: X
authors.lastname: Zhong
authors.affiliation: Department of Endorinology and Metabolism, The Second Hospital of Anhui Medical University, 678, Furong Road, Hefei, Anhui, 230601, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Du
authors.affiliation: Department of Endorinology and Metabolism, The Second Hospital of Anhui Medical University, 678, Furong Road, Hefei, Anhui, 230601, China.
authors.forename: C
authors.initials: C
authors.lastname: Cai
authors.affiliation: Department of Endorinology and Metabolism, The Second Hospital of Anhui Medical University, 678, Furong Road, Hefei, Anhui, 230601, China.
authors.forename: T
authors.initials: T
authors.lastname: Pan
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000008:administration & dosage; D017209:Apoptosis / Q000187:drug effects*; D009202:Cardiomyopathies / Q000188:drug therapy* / Q000209:etiology / Q000473:pathology; D019587:Dietary Supplements; D007037:Hypothyroidism / Q000150:complications / Q000503:physiopathology*; D008297:Male; D018384:Oxidative Stress; D051381:Rats; D017207:Rats, Sprague-Dawley; D013974:Thyroxine / Q000008:administration & dosage*; D014810:Vitamin E / Q000008:administration & dosage*
chemical_list: D000975:Antioxidants; D014810:Vitamin E; D013974:Thyroxine
keywords: Hypothyroidism; Levothyroxine; Myocardial apoptosis index; Oxidative stress; Vitamin E