Figure 2.

Domperidone Enhances β Cell Proliferation by Antagonizing the Dopamine Apoptotic Signal in Islets

Treatment with dopamine increased EdU incorporation and decreased cell event positivity in β cells, analyzed by immunocytochemistry.

(A–B′) Representative images are shown. EdU incorporation increased in insulin-positive (Ins⁺) cells treated with domperidone (DPD).

(C) The proportion of EdU-positive proliferating cells within the Ins⁺ cell population increased following DPD treatment (12 independent experiments, each with three to four replicates).

(D) Total cell numbers per well, showing the number of endocrine cells (PP⁺, Sst⁺, Gcg⁺, Ins⁺), exocrine cells (Amy⁺), and mesenchymal cells (Vim⁺) in the culture on day 5 without (Cont) or with DPD. The data shown in Cont are identical to those in Figure 1F d5 (three independent experiments, each with four replicates).

(E–F′) The Ins⁺ cells in the islet cells become cell event-positive apoptotic cells on day 5. The appearance of apoptosis was inhibited by DPD treatment on days 3–5.

(G) Percentage of apoptotic cells among the Ins⁺ cells on day 5 (six independent experiments, each with three to four replicates).

(H) The number of Ins⁺ cells per well after 4 days of chemical treatment (days 3–7) (four independent experiments, each with three to four replicates). Data represent mean ± SD. ^∗∗p < 0.01 compared with control (open bars); NS, not significant. DA, dopamine. Scale bar, 50 μm.