Fig. 1.

(A) In vitro effect of zinc and zinc+T₃ on active thymulin production from thymic explant of PTU mice during two times of culture (30 min and 6 h). TECs number detected after 6 h of culture. Photos of fluorescent TECs (white arrow) are reported. Lecture (40×); photos (magnitude 10×). [Note: yellow spots are aspecific fluorescence impossible to avoid due to fraying of the thymus in the medium after 6 h of culture with new perivascular spaces imbued in the medium (Mocchegiani et al., 1998b)]. *P<0.01 vs. young (ANOVA, Bonferroni test). TECs proliferation and percentages are also reported. Significant decrements in PTU mice (β) are observed as compared to young (α) (P<0.01). Zinc restores them (γ) with no synergism after zinc+T₃ addition (δ) as compared to zinc alone (γ). Mean±SD of four cultures with two thymuses each. Number of TECs and photos were performed using anti-thymulin MoAb. Anti-keratin MoAb for testing TEC percentage. No differences in in situ TECs number were observed between anti-thymulin and anti-keratin MoAbs (data not shown). (B) Active thymulin production, TEC proliferation and percentage in pure murine TEC cell line 9IT-45R1) and after the addition of zinc, T₃, zinc+T₃ and corticosterone. Mean±SD of four experiments each on triplicate cultures. Active thymulin was evaluated by the rosette assay, TEC percentage by using anti pan-cytocheratin FITC MoAb. *P<0.05 as compared to none (control culture) or T₃. **P<0.01 as compared to none (ANOVA, Bonferroni test).