ORIGINAL ARTICLE Hypoandrogenism related to early skin wound healing resistance in rats A. Petroianu, D. F. M. Veloso, L. R. Alberti, J. A. Figueiredo, F. H. O. Carmo Rodrigues & B. G. M. Carvalho E Carneiro Federal University of Minas Gerais, Belo Horizonte, MG, Brazil Introduction Wound healing may be impaired by several conditions, such as hyperglycaemia, hypoproteinaemia, infections and impaired collagen synthesis. Androgens cause positive nitrogen balance and increase protein synthesis. Due to the anabolic effect of these hormones, their use was proposed for accelerating wound healing. Several studies showed that wounds are sensitive to androgen stimulation and its deficiency causes anomalous healing (Ashcroft & Mills, 2002; Fimmel & Zouboulis, 2005; Gilliver et al., 2006, Gilliver et al., 2007). The pro-mitotic activity of these mediators, in physiological concentrations, seems to increase the production of granulation tissue in wounds. On the other hand, high doses of testosterone have an inhibitory effect on granulation tissue (Gilliver et al., 2009). About 95% of serum testosterone is secreted by the interstitial cells of the testis, a process under control of interstitial cell stimulating hormone (luteinising hormone), produced in the anterior pituitary. The remaining testosterone is synthesised in the adrenal glands. Therefore, bilateral orchiectomy causes near total testosterone depletion, which allows assessing the effects of the absence of this hormone in different organic reac- tions (Yuan & Balk, 2009). Due to the need of more investigations comparing the effects of testosterone in skin regeneration, this study had the objective of compar- ing skin healing resistance in different age groups and dif- ferent post-operative periods. Material and methods This study was performed in accordance to the recom- mendations of the International Guidelines of Animal Protection (2006) and approved by the Ethics Committee in Animal Experimentation of the Universidade Federal de Minas Gerais (Rollin, 2006). A total of 44 male Wistar rats (Rattus norvegicus albinus) were used. They were taken from the Central Animal Laboratory of the Instituto de Cieˆncias Biolo ´gicas of the University and were transferred to the Central Keywords Hypogonadism—orchiectomy—rat— testosterone—wound healing Correspondence Prof. Andy Petroianu, Avenida Afonso Pena, 1626 – Apto. 1901, Belo Horizonte, MG 30130-005, Brazil. Tel./Fax: (55-31)-3274-7744; E-mail: petroian@medicina.ufmg.br Accepted: April 27, 2009 Summary The purpose of this study was to verify the effect of testosterone depletion on healing of surgical skin wounds at different ages and post-operative periods. Forty-four Wistar male rats were divided into four groups: Group 1Y (n = 11) – young control, sham-operated rats (30-day old); Group 1A (n = 10) – adult control, sham-operated rats (3 to 4-month old); Group 2Y (n = 10) – young rats after bilateral orchiectomy; and Group 2A (n = 11) – adult rats after bilat- eral orchiectomy. After 6 months, a linear incision was performed on the dorsal region of the animals. The resistance of the wound healing was measured in a skin fragment using a tensiometer, on the 7th and 21st post- operative days. The wound healing resistance was higher in Group 1Y than in Group 2Y after 7 days (P < 0.05). Wound healing resistance at 21 days was higher than at 7 days in all groups (P < 0.05). Late wound healing resistance was not different between young and adult rats. It is concluded that bilateral orchiectomy diminished the wound healing resistance only in young animals at the 7th post-operative day. ª 2010 Blackwell Verlag GmbH Æ Andrologia 42, 117–120 117