CLDN1 and atrial fibrillation: Lastly, in comparison with the ABX group, hc toxin was positively correlated with the brain barrier function indexes (Occludin, Claudin-1, and ZO-1) and immune function indexes (IL-10, Foxp3, and PD-1) in the AF group, while zectran and pilocapine were negatively correlated with those aforementioned indexes (Figure 8I).