Effect of 17beta-estradiol replacement in pain perception of prepubertal and young female rats in a model of postoperative pain

• Grant number: 14/03985-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: September 01, 2014
• End date: August 31, 2015
• Field of knowledge: Health Sciences - Medicine - Surgery
• Principal Investigator: Hazem Adel Ashmawi
• Grantee: Caroline Firmino Lemes da Silva
• Host Institution: Faculdade de Medicina (FM). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Prevalence of pain in women is higher than in men. Women feel more pain, in more regions, look more for doctors and tak more analgesic than men. Yet the mechanisms involved are not clear. Besides psichosocial components, gonadal hormones seem to be involved to these differences. Hormonal action may occur at organizational or activation levels. Aim: The aim of this study is to evaluate pain behavior response in a postoperative pain model (plantar incision) in oophorectomized rats before and after puberty, receiving or not 17²-estradiol replacement. Methods: Twenty pre pubertal (14 days of life) rats and 20 young female rats (56 days of life) will be submitted to bilateral oophorectomy. Half of the animals of each age will receive implants of 17²-estradiol and the other half of placebo implants. Fourteen days later, plantar incision in the right posterior hindpaw will be performed in all animals. All surgical procedures will be performed under general anesthesia. Pain behavior tests will be made - paw withdrawal latency after mechanical stimuli and guarding pain behavior. Pain behaviors will be evaluated in the following time points: baseline, 2h after incision and on the 1st, 2nd, 3rd, 4th, 7th, 10th and 14th.