Fig. 4. Effects of PTX3 on matrix organization and cumulus expansion. (A) PTX3 is necessary for matrix assembly and cumulus expansion. COCs (20/20 µl) were cultured for 16 hours in the presence of FSH and FBS, and with 1 µg/ml recombinant PTX3 where indicated. HA evaluation was performed as indicated in Materials and methods. Cumulus expansion and HA distribution between matrix and medium were assessed for (a) Ptx3^+/– cumuli, (b) Ptx3^–/– cumuli and (c) Ptx3^–/– cumuli cultured with recombinant PTX3. Reported data refer to one representative experiment of three performed. Scale bar: 100 µm. (B) Degradation of expanded cumulus matrix is not affected by recombinant PTX3. Degradation of the HA-rich matrix was assessed at 24 and 28 hours of culture by calculating the proportion of the total HA released in the culture medium, as described previously (D'Alessandris et al., 2001). In the upper panel the total amount of HA (pmol hexosamine)/COC at each time culture is reported. Error lines indicate the standard deviation of duplicate cultures.