Figure 4. Expression of VDAC3, CLCN3, SLC4A4, and Na⁺-K⁺-ATPase by RT–PCR, and the protein expression of ZO-1 and Na⁺-K⁺-ATPase by immunocytochemistry. A: RT–PCR detection of the mRNA expression of VDAC3, CLCN3, SLC4A4, and Na⁺-K⁺-ATPase. B: western blot analysis of Na⁺-K⁺-ATPase . C: Immunostaining of ZO-1. D: Immunostaining of Na⁺-K⁺-ATPase.