Dissertação
Perfil das células germinativas após degeneração testicular induzida pelo busulfan
Fecha
2013-02-21Registro en:
GUTIERREZ, Karina. Germ cells profile after testicular degeneration induced by busulfan. 2013. 50 f. Dissertação (Mestrado em Medicina Veterinária) - Universidade Federal de Santa Maria, Santa Maria, 2013.
Autor
Gutierrez, Karina
Institución
Resumen
The chemotherapeutic busulfan is widely used in studies of spermatogonial stem cells
kinetics and studies of male infertility. However it effects on male germ cells in different
animal lineages or species are unclear. The objective of this study was to assess the damage
caused by busulfan in male mice spermatogenesis of two distinct lineages. The analyzed
parameters were the mRNA pattern expression profile of spermatogonial stem cells (SSC)
markers, analysis of spermatozoa motility, vigor and morphology, germinal epithelium
histology and fertility recovery analysis. The animals received a single dose of 40 mg kg-1 of
busulfan or vehicle. Past 30 days of the drug injection, the mice were weighted and
anesthetized and had one of the testes and epididymis surgically removed. This procedure did
not cause any damage to the other testis, once mice that had one of the testes removed were
capable to generate offspring. From these testes, were evaluated the tissue histology and
mRNA gene expression of spermatogonial stem cell (SSC) markers. The motility, vigor and
spermatozoa morphology were analyzed from cauda epididymal spermatozoa. After 90 days
of the drug injection, the mice were weighted, anesthetized and had the other testis removed
for the same analyzes procedure. The analysis at 30 and 90 days after drug injection were
from the same animals, minimizing the variation in individual response between periods. It
was observed that, for Balb/C lineage, independent of the analyzed period, the busulfan
treated animals showed a severe testicular degeneration, with loss of SSC, decreased motility
and spermatozoa vigor and increased number of defective spermatozoa. In mRNA expression
it was observed a marked reduction in Nanos2 expression, and an increase in Gdnf and Plzf
gene expression. For animals of Swiss lineage, it was observed that at 30 days after the
busulfan injection, the results obtained were similar to that obtained for Balb/C lineage,
except in gene expression, which remained unchanged. However, 90 days after the drug
injection, these animals show germinal epithelium almost normal, with spermatogenic
lineage. They also show an increase in testicular and epididymal mass, spermatozoa motility
and vigor and an increase in number of normal spermatozoa, did not differing from the
control group. Moreover, this recovery was confirmed by the offspring obtained after matting
with virgin females. The male mice utilized in these tests were not submitted to testes
removal. These results shows the variation of busulfan effects in two distinct mice lineages,
being the drug effective to cause a severe testicular degeneration for more than 90 days in
Balb/C lineage, but not in Swiss lineage, due to genetic variations.