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Effects of resveratrol on sperm parameters, reproductive capacity and quality of embryos obtained from adult rats submitted to surgical left-sided varicocele in peripuberty

Grant number: 16/14546-3
Support type:Regular Research Grants
Duration: February 01, 2017 - January 31, 2019
Field of knowledge:Health Sciences - Medicine
Principal Investigator:Sandra Maria Miraglia Valdeolivas
Grantee:Sandra Maria Miraglia Valdeolivas
Home Institution: Escola Paulista de Medicina (EPM). Universidade Federal de São Paulo (UNIFESP). Campus São Paulo. São Paulo , SP, Brazil
Assoc. researchers:Camila Cicconi Paccola ; Samara Urban de Oliva ; Vanessa Vendramini Vilela

Abstract

Male infertility has expressively increased in the population. Varicocele is the most common cause of infertility that can be repaired. Its first signs coincide with the pubertal onset and interfere with the testicular development. Although the mechanisms that lead to male infertility involving varicocele are not clear, the disease is known to rise testicular temperature, provoking hypoxia and the increase of oxidative stress. The free radicals generated disrupt sperm cell membrane and DNA, thus affecting its viability, capacitation and acrosome reaction. Antioxidants can protect the human body against the side effects caused by the oxidative stress by delaying the progress of many diseases. Therefore, they have been studied as a therapeutic alternative or adjuvant therapy in order to prevent and repair male infertility. The goal of the present study is to investigate the role of resveratrol (phytoalexin that has antioxidant properties found in many plants) on the reproductive parameters and oxidative stress of adult rats (Wistar lineage) presenting experimentally-induced varicocele from peripuberty. Left-sided surgically-induced varicocele will be produced at 41dpp through the partial ligature of the left renal vein in the animals of the groups varicocele (V, n=82) and varicocele treated with resveratrol (VR, n=82). The group Sham control (S, n=46) will be submitted to a similar surgical procedure without the ligature of the renal vein, along with the treatment with carboxymethylcellulose (resveratrol vehicle). The groups resveratrol (R, n=46) and VR will be daily treated with 300 mg/kg of body weight of resveratrol (gavage). At 100dpp the animals will be submitted to euthanasia and the testes will be excised for the evaluation of the daily sperm production, oxidative stress and markers of apoptotic pathways (Bax and Bcl-2 proteins, using western blot). Plasmatic and testicular dosages of testosterone (ELISA assay) will also be investigated. The epididymides will be used for assessing sperm counts, sperm transit time, oxidative stress (using techniques to detect hydrogen peroxide, malondialdehyde and antioxidant enzymes) and for histopathological, morphometric and stereological analyses and immunoenzymatic detection of apoptosis (TUNEL method). Hydrogen peroxide detection will also be carried out in the testis; all the analyses will be undertaken in both ipsi and contralateral epididymides and testes in relation to varicocele. The sperm collected from the cauda of both left and right epididymides will be respectively evaluated for the chromatin structure (Acridine orange assay, using flow cytometry), protamination level (using CMA3 method in flow cytometry), acrosome integrity and capacitation (using chlortetracycline under epifluorescence microscopy), mitochondrial function (using MitoTracker Green FM stain under epifluorescence microscopy), mitochondrial activity (Cytochrome c oxidase method, using ELISA), as well as the lipid peroxidation level (BODIPY-C11 method, using flow cytometry). The reproductive capacity of the animals will also be evaluated at the end of treatment (100dpp). (AU)