JAK2 and metabolic dysfunction-associated steatotic liver disease: Fructose-induced NAFLD mice treated with a high-dose of kefir peptides showed a significant inhibition of the expression of OB-R (1.5-fold) and increased p-JAK2, STAT3 and p-STAT3 levels (1.8-, 2.1- and 2.4-fold, respectively) compared with the mock group.