Expression of proteins associated with necroptosis pathways in myocardial injury in diabetic rats

Objective To investigate the expression of necroptosis pathway related protienin diabetic myocardium, and its possible mechanism.

Methods The diabetic model of rats was prepared by intraperitoneal injection of 40mg/kg of streptozotocin on the basis of highcalories diet feeding, and divided into the normal group(CON group, n=6), highcalories group(HC group, n=6) and diabetes group(DM group, n=6).After 10 weeks, the left ventricular end diastolic diameter(LVEDD), left ventricular end systolic diameter(LVESD) and left ventricular ejection fraction(LVEF) were detected using ultrasound.The heart weight(HW), body weight(BW), and heart-body ratio(HW/BW) in three groups were measured after the rats were sacrificed.In three groups, the serum levels of tumor necrosis factor-α(TNF-α), interleukin-6(IL-6) and maleic dialdehyde(MDA) were detected using ELISA method, the apical tissue were stained using Masson, and the changes of RIPK1, RIPK3 and MLKL in myocardial tissue were detected using RT-PCR and Western blotting.

Results Compared with the CON group, the expression levels of HW, TNF-α, IL-6 and MDA increased, and the protein expression levels of RIPK1, RIPK3, and MLKL increased(P < 0.05 to P < 0.01), but the changes of the mRNA expression levels of MLKL were not obvious in HC group(P>0.05).Compared with the HC group, the HW/BW increased, the LVEF decreased, the levels of TNF-α, IL-6 and MDA expression increased, the mRNA and protein levels of RIPK1, RIPK3, and MLKL increased(P < 0.01), and the blue staining of Masson aggravated in DM group.

Conclusions High glucose status can induce the myocardial injury, increase the myocardial fibrosis and oxidation level, which may be related to the upregulation of the necroptosis pathway.