Abstract: BACKGROUND AND AIM: To explore the effect of Thioglycolic acid (TGA) on cytoplasmic maturation and related molecular factors of mouse oocytes. MATERIALS AND METHODS:Mouse oocytes were matured in vitro cultured with serial doses of TGA. Immunoflurescence staining was used to label cortical granules (CGs) and p44/42MAPK was measured by western blot. RESULTS: Rate of germinal vesicle-breakdown in each group reached 90％ and comparison was insignificant (P>0.05). Rate of first polar body decreased with increasing TGA dose, the comparison between control and treatments was significant (P<0.05).CGs of oocytes from all groups migrated to the cortex and formed a continuous layer under the cell membrane, but CGs density in the cytoplasm became higher with increasing TGA treatment dose. Obvious cortical granule free domain (CGFD) was observed at 0 mmol/L TGA, in 0.2 mmol/L TGA CGFD could still be seen, but not in 1.0 mmol/L and 2.5 mmol/L TGA groups. Meanwhile, TGA inhibited p44/42MAPK activation in 1.0 mmol/L and 2.5 mmol/L treatment groups. CONCLUSION: TGA exerted reproductive toxicity since it interfered with cytoplasmic maturation and MAPK activation of mouse oocytes.

Key words: thioglycolic acid;cortical granule;MAPK, oocyte;mouse