Postsurgical Administration of Estradiol Benzoate Decreases Tensile Strength of Healing Skin Wounds in Ovariectomized Rats

Background: The most effective method of increasing the level of estrogen in the wounds of post-menopausal women undergoing routine surgical procedures is by long-term preoperative administration. However, in the case of acute surgery or trauma, the most effective method of increasing the level of estrogen is administration immediately pre- or postsurgery. This study, therefore, was aimed at assessing the effect of postsurgical administration of estradiol benzoate on wound healing in ovariectomized (OVX) Sprague Dawley rats. Materials and methods: Three months prior to the wound healing experiment, 16 rats were anesthetized and underwent ovariectomy, while the other eight rats were sham operated. Two parallel full thickness skin incisions and two round full thickness skin excisions were performed on the dorsum of each rat. Dose of 10 μg/d of estradiol benzoate was administered to eight OVX rats for 6 d postoperatively, whereas the other animals received a placebo. After 6 d, all animals were sacrificed and samples removed for biomechanical and histological evaluation. Results: The mean wound tensile strength of OVX estrogen treated rats (9.54 ± 3.24 g/mm²) was significantly lower compared with vehicle-treated OVX animals (14.57 ± 4.12 g/mm²) as well as with control rats subjected to sham-OVX surgery (11.71 ± 3.33 g/mm²). Nevertheless, the histological evaluation in OVX estrogen treated rats showed a significantly increased process of neo-angiogenesis associated with slightly decreased collagen deposition. Conclusion: Our results indicate that the question of the clinical significance of this type of hormone replacement therapy remains open and requires further research.