ABSTRACT
<p><b>OBJECTIVE</b>To discuss the expression and significance of glial cell-derived neurotrophic factor (GDFN) receptor alpha 1 gene (GFR alpha 1) in the recovery spermatogenesis of mice.</p><p><b>METHODS</b>Adult Kunming mice were injected intraperitoneally with 2 doses of busulfan (10 mg/kg) 24 days apart so as to establish the recovery spermatogenesis model. Testes were harvested 1 w, 2 w, 3 w, 4 w, 6 w, 8 w and 10 w after the second injection, and normal testes were used as control. The recovery spermatogenesis was observed by light and electron microscopy, and the GFR alpha 1 mRNA was measured by semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) and in situ hybridization.</p><p><b>RESULTS</b>The expression of GFR alpha 1 mRNA increased significantly at 1 w and reached its peak at 2 w after the second injection [(104.72 +/- 24.4)% vs normal control, P < 0.01]; its expression reduced significantly at 3 w and reached its valley at 4 w [(20.77 +/- 4.25)% vs normal control, P < 0.01], and then increased gradually and restored to the normal level at 10 w. GFR alpha 1 mRNA was mainly expressed by undifferentiated spermatogonia.</p><p><b>CONCLUSIONS</b>In the course of recovery spermatogenesis, the expression of GFR alpha 1 plays a key role in turning the spermatogonial stem cell reactivity to GDNF, which promotes self-renewal at a high level, or results in differentiation at a low level.</p>