Spontaneously hypertensive rats (SHR) are frequently used as rat models of essential hypertension. The mechanism for the development of hypertension is complicated and it is unknown. The renin-angiotensin system (RAS) plays a key role in the control of blood pressure. Microarrays are a powerful tool for studying genetics. The purpose of this study was to investigate changes of gene expression in the heart tissues of SHR after losartan treatment to provide basic data that is useful in the early diagnosis of hypertension and gene treatment.

Rats were divided into three groups: the control (C) group; the hypertension (H) group (SHR), and the losartan (L) group; treated with losartan (10 mg/kg/day) in SHR. Rats were sacrificed at week 5 and microarray analysis was performed.

102 gene expressions including the genes associated with cell proliferation such as Raf1, Uchl1, Btla, Spock1 were increased. The other 139 gene expressions, including the genes related to the regulation of metabolism such as TFIID, Auf1, Bmp, Hub, Taf51 showed decreases in gene expression. A total of 31 genes were differentially expressed in the L group compared to the H group. Of these, 16 genes including the genes associated with macromolecule metabolism such as MGC105766, Ppp1r1a, Rpl3l showed increased expression. The other 15 genes including the genes associated with primary metabolism such as Mcpt4, Ngn3, Tdo, Ak2 Hyal2 showed decreased expressions.

According to microarray analysis, there was significant gene expression change in SHR compared with normal rats as well as significant gene expression changes after losartan treatment in SHR.