Myocardial interstitial remodeling and expressions of SHIP-1 and IL-6 in high-salt-induced hypertensive rats

Objective: To investigate myocardial interstitial fibrosis and the expressions of SH2 domain-containing inositol 5-phosphatase 1 (SHIP-1) and interleukin-6 (IL-6) in high-salt-induced hypertensive rats.Methods: Twenty-five SD male rats were randomly divided into control group and model group.The model group and the control group were fed respectively with high salt diet (containing 3%NaCl) and ordinary diet for 12 weeks.The rat tail artery pressure was measured once every two weeks.After 12 weeks, the rats'body and heart weight were weighed and the heart mass index (heart weight/body weight) was calculated.Hematoxylin-eosin (HE) staining and Masson staining were used to observe the histopathological changes of myocardium.The mRNA and protein expressions of SHIP-1 and IL-6 were detected by real-time fluorescence quantitative polymerase chain reaction (RT-qPCR) and immunohistochemistry, respectively.Results: Systolic blood pressure and heart mass index in the model group were higher than those in the control group after 12 weeks of feeding (P＜ 0.05).Compared with the control group, the myocardial tissue of rats in the model group was infiltrated by a large number of inflammatory cells, the collagen fiber significantly increased, and the collagen volume fraction (CVF) was higher than that in the control group (P＜ 0.05).The mRNA and protein expression of SHI-1 in the model group was lower than that in the control group while the mRNA and protein expression of IL-6 was higher than that in the control group (all P＜ 0.05).Conclusion: In high-salt-induced hypertensive rats, myocardial interstitial fibrosis remodeling is observed; SHI-1 expression is down-regulated while IL-6 expression is up-regulated.