title: Hypothyroidism improves random-pattern skin flap survival in rats.
abstract: BACKGROUND
  The protective effect of hypothyroidism against ischemic or toxic conditions has been shown in various tissues. We investigated the effect of propylthiouracil (PTU)/methimazole (MMI)-induced hypothyroidism and acute local effect of MMI on the outcome of lethal ischemia in random-pattern skin flaps.
  
  
  METHODS
  Dorsal flaps with caudal pedicles were elevated at midline and flap survival was measured at the seventh day after surgery. The first group, as control, received 1 mL of 0.9% saline solution in the flap before flap elevation. In groups 2 and 3, hypothyroidism was induced by administration of either PTU 0.05% or MMI 0.04% in drinking water. The next four groups received local injections of MMI (10, 20, 50, or 100 μg/flap) before flap elevation. Local PTU injection was ignored due to insolubility of the agent.
  
  
  RESULTS
  Hypothyroidism was induced in chronic PTU- and MMI-treated groups, and animals in these groups showed significant increase in their flap survival, compared to control euthyroid rats (79.47% ± 10.49% and 75.48% ± 12.93% versus 52.26% ± 5.75%, respectively, P < 0.01). Acute local treatment of skin flaps with MMI failed to significantly affect the flap survival.
  
  
  CONCLUSIONS
  This study demonstrates for the first time that hypothyroidism improves survival of random-pattern skin flaps in rats.
authors.affiliation: Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Sina
authors.initials: S
authors.lastname: Rahimpour
authors.forename: Behtash Ghazi
authors.initials: BG
authors.lastname: Nezami
authors.forename: Negin
authors.initials: N
authors.lastname: Karimian
authors.forename: Maryam
authors.initials: M
authors.lastname: Sotoudeh-Anvari
authors.forename: Farzad
authors.initials: F
authors.lastname: Ebrahimi
authors.forename: Shayandokht
authors.initials: S
authors.lastname: Taleb
authors.forename: Naser
authors.initials: N
authors.lastname: Mirazi
authors.forename: Ahmad Reza
authors.initials: AR
authors.lastname: Dehpour
mesh_terms: D000818:Animals; D013956:Antithyroid Agents / Q000494:pharmacology; D062109:Dermatologic Surgical Procedures / Q000379:methods*; D004195:Disease Models, Animal; D007037:Hypothyroidism / Q000139:chemically induced*; D007511:Ischemia / Q000188:drug therapy* / Q000517:prevention & control; D008297:Male; D008713:Methimazole / Q000494:pharmacology*; D011441:Propylthiouracil / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D019651:Plastic Surgery Procedures / Q000379:methods; D012867:Skin / Q000098:blood supply; D013524:Surgical Flaps / Q000098:blood supply*; D013961:Thyroid Gland / Q000187:drug effects
chemical_list: D013956:Antithyroid Agents; D008713:Methimazole; D011441:Propylthiouracil