USE OF MESENCHYMAL STEM CELLS IN NELORE BULLS SUBMITTED TO TESTICULAR DEGENERATION BY ESCROTAL INSULATION

Abstract

Testes function are spermatogenesis and androgenesis. To maintain their functions, they should be between 2 and 6 ° C below body temperature. Elevated ambient temperatures can affect testicular thermoregulation causing testicular degeneration, which affects its functions. Mesenchymal stem cells (MSCs) have anti-inflammatory, antiapoptotic and regenerative characteristics, being a promising treatment for numerous diseases. In this way the objective will be evaluate the effect of intratesticular treatment with MSCs in Nelore bulls with testicular degenerations induced by scrotal insulation. For this purpose, 20 Nelore bulls will be used, divided into four experimental groups: control group (GC), testicular insulation group (GI), MSCs group (GCT) and testicular insulation group treated with MSCs (GICT). The animals of the GI and GICT groups will be submitted to testicular insulation using a thermal bag for 96 hours. After this period the animals of the GCT and GICT groups will receive intratesticular administration of 5 to 10x106 MSCs, previously isolated and characterized. To evaluate the effects of testicular degeneration and treatment with MSCs, will be performed every 15 days for 20 weeks, testicular measurement, harvest and immediate seminal analysis, analysis of sperm morphology, scrotal thermography, blood collection for testosterone dosage and seminal freezing for posterior computerized evaluation of spermatic kinetics and evaluation of plasma and acrosomal membrane integrity, DNA fragmentation index and concentration of reactive oxygen species by flow cytometry. In the 20th week bull´s orchiectomy will be performed for histological and immunohistochemical evaluation of the integrity of the testicular tissue and expression of apoptotic and antiapoptotic factors. The results obtained will be extremely important for the knowledge of the mechanisms involved in testicular degeneration and to evaluate the use of MSCs as a therapeutic method. (AU)