Effects of Serpine2 overexpression and addition of exogenous SERPINE2 on cumulus expansion.

A, The morphologies of untreated and treated COCs after 16 h of IVM culture are shown: a, IVM control; b, transfected with the control plasmid; c, transfected with the Serpine2-expressing plasmid. d, Cultured COCs transfected with the Serpine2-expressing plasmid were fixed on slides, and SERPINE2 protein expression was monitored by epifluorescence microscopy. The red fluorescence represents coexpression of SERPINE2 and the red fluorescent protein. e–g, COCs were incubated with 0.03, 0.06, and 0.12 mg/ml SERPINE2 protein, respectively. B, qRT-PCR revealed the relative Serpine2 mRNA levels in cumulus cells transfected with Serpine2-expressing or vehicle plasmids. C, The extent of cumulus expansions are shown as COC diameters after 16 h of IVM culture (n = 100 for each group). D, MII oocyte maturation rate after 16 h of IVM culture. B–D, Data represent means ± SD for five independent experiments. ^#P<0.001, *P<0.0001 vs. untreated control or control plasmid.