After preculture, rat islets were cultured for 1 week in the presence of G5, G10 or G30 alone or with 100 µmol/l ZnCl2. Islets were then fixed in paraformaldehyde solution (4%) and embedded in paraffin. Nuclei (DAPI), insulin and MT1a/2a were detected by immunohistochemistry in 5 µm-thick islets sections. Bar scale = 100 µm. A–D: islets cultured in G5; E–H : islets cultured in G5+100 µM ZnCl2 (G5+ Zn); I-L: islets cultured in G10; M-P: islets cultured in G10+100 µM ZnCl2 (G10+ Zn); Q–T: islets cultured in G30; U–X: islets cultured in G30+100 µM ZnCl2 (G30+ Zn). A,E,I,M,Q,U: DAPI staining; B,F,J,N,R,V: insulin staining; C,G,K,O,S,W: MT1a/2a staining; D,H,L,P,T,X: merge. Results are representative for 2 to 3 experiments.