As a result of aquaporins upregulation and Muc5AC downregulation, it is reasonable to propose that, except for anti-inflammatory effects, MZP controls the risk of COPD by inhibiting airway mucus obstruction, which could induce chronic cough and expectoration, while a paroxysmal cough is an independent risk factor for COPD [42, 43]. Here, MUC5AC is linked to chronic obstructive pulmonary disease.