|Support type:||Scholarships in Brazil - Scientific Initiation|
|Effective date (Start):||January 01, 2012|
|Effective date (End):||June 30, 2013|
|Field of knowledge:||Biological Sciences - Morphology - Histology|
|Principal Investigator:||Estela Sasso Cerri|
|Home Institution:||Faculdade de Odontologia (FOAr). Universidade Estadual Paulista (UNESP). Campus de Araraquara. Araraquara , SP, Brazil|
Busulfan, a chemotherapeutic drug, causes damage in proliferative tissues such as the seminiferous epithelium. Regarding that vitamin B12 stimulates DNA synthesis, the effect of this vitamin in the recovery of the damaged seminiferous epithelium by busulfan, mainly in the spermatogonial cells, will be evaluated. Sixty-four male rats will be distributed into 8 groups (n=8/group). The animals will receive daily intraperitoneal injections of 3 µg of vitamin B12 during 10 (GB, GVVit, GRec and GVrec-1) or 17 (GRecVit and GVRec-2) days. These animals will also receive intraperitoneal injections of 10 mg/Kg of Busulfan (GB, GRec e GRecVit) or polyethylene glycol (GVVit, GVRec-1 and GVRec-2) in the 1st and 4th days. In the control groups (GV e GVRec-3), the animals will receive polyethylene glycol (1st and 4th days) and saline solution during the other days. The animals will be anaesthetized and the blood will be collected for the hemogram evaluation. The testes will be removed and embedded in glycol methacrylate. In 45 tubular cross-sections per animal, stained by H.E., 15 tubules at specific stages of the seminiferous cycle (I-VI, VII-VIII and IX-XIV) will be randomized selected and the total and epithelial tubular areas will be measured. The frequency of damaged tubules will also be obtained. The number of spermatogonia in the tubules at stages IX-XIV will also be quantified. The results will be statistically analyzed (pd0.05).