Chinese Journal of Pathophysiology · Oct 23, 2026
Protective effects of upregulating the inwardly rectifying potassium channel Kir2.1 in aging rat hearts and AC16 cardiomyocytes
By 乔碧瑶
OBJECTIVE: To observe the effects of upregulating inwardly rectifying potassium channel 2.1 (inwardly-rectifying potassium channel 2.1,Kir2.1) on the hearts of aged SD rats and senescent AC16 cardiomyocytes; and to observe the effects of modulating macrophage Kir2.1 on cardiomyocyte senescence, thereby investigating whether upregulating Kir2.1 channels can protect aging hearts by inhibiting oxidative stress and improving the inflammatory microenvironment. METHODS: (1) In vivo experiments: SD rats were divided into young control (2 months old), aged (18 months old), aged+zacopride (zacopride,Zac;15 μg·kg-1·d-1), and aged+Zac+chloroquine (7.5 μg·kg-1·d-1) groups, with 6 rats per group. Treatment began at 18 months of age, with daily intraperitoneal injections for 7 consecutive weeks. RT-qPCR was used to detect the mRNA expression of myocardial senescence markers (P21 and P53), the senescence-associated secretory phenotype [interleukin-1β (interleukin-1β,IL-1β) and IL-6], and Kir2.1/KCNJ2 in rats. (2) In vitro cell experiments: D-galactose (D-galactose,D-gal;10 g/L) was used to induce senescence in AC16 cardiomyocytes, and lipopolysaccharide (lipopolysaccharide,LPS;500 μg/L) was used to induce M1 polarization in RAW264.7 macrophages. Cardiomyocytes were randomly divided into control, D-gal, D-gal+Zac (1 μmol/L), and D-gal+Z 2ac+BaCl(1 μmol/L) groups. The coculture system was divided into normal control (M0 macrophages+normal AC16), inflammatory (M1 macrophages+normal AC16), inflammatory senescence (M1 macrophages+senescent AC16), Zac intervention (Zac-treated macrophages+senescent AC16), and BaCl2 blocker (Zac+BaCl2-treated macrophages+senescent AC16) groups. RT-qPCR and Western blot were used to detect the expression of Kir2.1/KCNJ2, P21, P53, IL-1β, and IL-6 in cardiomyocytes; senescence-associated β-galactosidase staining was used to assess cardiomyocyte senescence; and reactive oxygen species (reactive oxygen species,ROS) staining was used to assess oxidative stress levels in cardiomyocytes. RESULTS: Zac can delay senescence in SD rat hearts and AC16 cardiomyocytes in a Kir2.1-dependent manner, as evidenced by significantly reduced expression levels of P21, P53, IL-1β, and IL-6; Zac reduced D-gal-induced senescence-associated β-galactosidase activity and ROS levels in cardiomyocytes, protecting cardiomyocytes by reducing their oxidative stress levels. Coculture with LPS-treated macrophages further aggravated cardiomyocyte senescence. Upregulating macrophage Kir2.1 can inhibit inflammatory cell activation and the production and release of inflammatory mediators, protecting senescent cardiomyocytes by improving the inflammatory microenvironment. CONCLUSIONS: Upregulating Kir2.1 in rat hearts can delay cardiac aging in rats; upregulating cardiomyocyte Kir2.1 can reduce cellular oxidative stress levels, alleviate D-gal-induced cell injury, and delay cardiomyocyte senescence; upregulating macrophage Kir2.1 can inhibit inflammatory cell activation and the production and release of inflammatory mediators, protecting senescent cardiomyocytes by improving the inflammatory microenvironment.