Objective:To evaluate the role of ZIP7 in sepsis-induced cardiomyopathy in mice.Methods:Ninety wild-type and 90 cardiomyocyte-specific knockout ZIP7 (ZIP7 cKO) male C57BL/6 mice, aged 6-8 weeks, weighing 20-25 g, were divided into 2 groups using a random number table method: wild-type sham operation group (Sham group) and wild-type sepsis group (Sep group), ZIP7 cKO sham operation group (cKO + Sham group) and ZIP7 cKO sepsis group (cKO + Sep group), with 45 mice in each group. The sepsis-induced cardiomyopathy model was developed using the cecal ligation and puncture in anesthetized mice. Twenty mice were randomly selected to record the survival for 10 days postoperatively. At 18 h after surgery, the left ventricular ejection fraction (LVEF) and fractional shortening (LVFS) were measured by echocardiography, and serum concentrations of cardiac troponin T (cTnT), tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) were measured by enzyme-linked immunosorbent assay. The contents of hydroxyl radical (·OH) and peroxynitrite anion (ONOO -) were determined using a colorimetric assay, the morphology of myocardial mitochondria was observed with a transmission electron microscope, and the expression of dynamin-related protein 1 (Drp1), mitofusin-2 (Mfn2), and optic atrophy 1 (Opa1) in myocardial tissues was detected using Western blot. Results:Compared to Sham group, the survival rate, LVEF and LVFS were significantly decreased, serum concentrations of cTnT, TNF-α and IL-6 were increased, the contents of ·OH and ONOO - in myocardial tissues were increased, the expression of Drp1 was up-regulated, the expression of Mfn2 and Opa1 was down-regulated ( P<0.05), myocardial cells exhibited mitochondrial swelling, and marked destruction of mitochondrial cristae was observed in Sep group, and no significant differences were found in the aforementioned parameters in cKO+ Sham group ( P>0.05). Compared to Sep group, the survival rate, LVEF and LVFS were significantly increased, serum concentrations of cTnT, TNF-α and IL-6 were decreased, the contents of ·OH and ONOO - in myocardial tissues were decreased, the expression of Drp1 was down-regulated, the expression of Mfn2 and Opa1 was up-regulated ( P<0.05), and mitochondrial swelling in myocardial cells was mild, with less dissolution and destruction of mitochondrial cristae in cKO+ Sep group. Conclusions:Myocardial ZIP7 can promote mitochondrial fusion and inhibit mitochondrial fission, potentially contributing to the mechanism of sepsis-induced cardiomyopathy in mice.

Objective:To evaluate the role of ZIP7 in sepsis-induced cardiomyopathy in mice.Methods:Ninety wild-type and 90 cardiomyocyte-specific knockout ZIP7 (ZIP7 cKO) male C57BL/6 mice, aged 6-8 weeks, weighing 20-25 g, were divided into 2 groups using a random number table method: wild-type sham operation group (Sham group) and wild-type sepsis group (Sep group), ZIP7 cKO sham operation group (cKO + Sham group) and ZIP7 cKO sepsis group (cKO + Sep group), with 45 mice in each group. The sepsis-induced cardiomyopathy model was developed using the cecal ligation and puncture in anesthetized mice. Twenty mice were randomly selected to record the survival for 10 days postoperatively. At 18 h after surgery, the left ventricular ejection fraction (LVEF) and fractional shortening (LVFS) were measured by echocardiography, and serum concentrations of cardiac troponin T (cTnT), tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) were measured by enzyme-linked immunosorbent assay. The contents of hydroxyl radical (·OH) and peroxynitrite anion (ONOO -) were determined using a colorimetric assay, the morphology of myocardial mitochondria was observed with a transmission electron microscope, and the expression of dynamin-related protein 1 (Drp1), mitofusin-2 (Mfn2), and optic atrophy 1 (Opa1) in myocardial tissues was detected using Western blot. Results:Compared to Sham group, the survival rate, LVEF and LVFS were significantly decreased, serum concentrations of cTnT, TNF-α and IL-6 were increased, the contents of ·OH and ONOO - in myocardial tissues were increased, the expression of Drp1 was up-regulated, the expression of Mfn2 and Opa1 was down-regulated ( P<0.05), myocardial cells exhibited mitochondrial swelling, and marked destruction of mitochondrial cristae was observed in Sep group, and no significant differences were found in the aforementioned parameters in cKO+ Sham group ( P>0.05). Compared to Sep group, the survival rate, LVEF and LVFS were significantly increased, serum concentrations of cTnT, TNF-α and IL-6 were decreased, the contents of ·OH and ONOO - in myocardial tissues were decreased, the expression of Drp1 was down-regulated, the expression of Mfn2 and Opa1 was up-regulated ( P<0.05), and mitochondrial swelling in myocardial cells was mild, with less dissolution and destruction of mitochondrial cristae in cKO+ Sep group. Conclusions:Myocardial ZIP7 can promote mitochondrial fusion and inhibit mitochondrial fission, potentially contributing to the mechanism of sepsis-induced cardiomyopathy in mice.

Objective:To evaluate the effect of losartan on acute kidney injury (AKI) and the relationship with mitochondrial fusion-fission in septic mice.Methods:One hundred and twenty-eight SPF male C57BL/6J mice, aged 6-8 weeks, weighing 20-25 g, were divided into 4 groups ( n=32 each) using a random number table method: sham operation group (Sham group), sham operation+ losartan group (Sham+ LOS group), sepsis-associated AKI group (SA-AKI group), and sepsis-associated AKI+ losartan group (SA-AKI+ LOS group). Sepsis was induced by cecal ligation and puncture in anesthetized mice. Sham+ LOS group and SA-AKI+ LOS group received intraperitoneal injection of losartan 5 mg/kg, once a day, for 3 consecutive days, starting from 3 days before sham operation or developing the model. The equal volume of solvent was given instead in Sham group and SA-AKI group. Twenty mice were randomly selected to observe the survival 7 days after surgery. At 24 h after sham operation or establishing the model, serum blood urea nitrogen (BUN) and creatinine (Cr) concentrations were determined by the colorimetric method, and serum concentrations of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and high-mobility group box 1 protein (HMGB1) were measured using enzyme-linked immunosorbent assay. Renal tissues were obtained for microscopic examination of pathological changes which were scored and for determination of mitochondrial membrane potential (using JC-1 method) and expression of dynamin-related protein 1 (Drp1) and mitofusin-2 (Mfn2) (using Western blot). Results:Compared with Sham group, the survival rate was significantly decreased, the serum BUN, Cr, TNF-α, IL-6 and HMGB1 concentrations and renal tubular injury score were increased, the ATP content and MMP were decreased, the expression of Drp1 was up-regulated, the expression of Mfn2 was down-regulated ( P<0.05), and pathological changes were found in renal tissues in SA-AKI group and SA-AKI+ LOS group. Compared with SA-AKI group, the survival rate was significantly increased, serum concentrations of BUN, Cr, TNF-α, IL-6 and HMGB1 and renal tubular injury score were decreased, the ATP content and MMP were increased, the expression of Drp1 was down-regulated, the expression of Mfn2 was up-regulated ( P<0.05), and the pathological changes of renal tissues were significantly attenuated in SA-AKI+ LOS group. Conclusions:Losartan can alleviate AKI in septic mice, and the mechanism may be related to promoting mitochondrial fusion and inhibiting mitochondrial fission.