MARcKS and nAP-22 proteins mRnA expression in renal cortex and renal medulla of rats with spontaneous hypertension

Objective. To study the changes in mRNA expression level of two main protein kinase C substrates — MARCKS and NAP-22 — in rats with spontaneous hypertension (SHR rats) and in normotensive control rats (WKY rats) in renal cortex, renal medulla and total kidney. We also aimed at the identification of possible interstrain differences between the mRNA expression levels.Design and methods.We assessed the level of MARCKS and NAP-22 mRNA by real-time polymerase chain reaction in male SHR and WKY (as a normotensive control) rats.Results. In SHR rats, MARCKS mRNA expression level in renal cortex was 1,5 times higher than in renal medulla (p = 0,0001) and also higher than in total kidney (p = 0,001), in renal medulla it was lower than in total kidney (p = 0,002). In WKY rats, MARCKS mRNA expression level in renal cortex was higher than in renal medulla (p = 0,0005). There was no differences neither between renal cortex and total kidney (p = 0,011), nor between renal medulla and total kidney (p = 0,716). In SHR rats, NAP-22 mRNA expression level in renal cortex was twofold higher than in renal medulla (p = 0,001), in renal medulla it was lower than in total kidney (p = 0,005), the differences between renal cortex and total kidney were less significant (p = 0,011). In WKY rats, NAP-22 mRNA expression level in renal cortex was 1,5 times higher than in renal medulla (p = 0,001), while in renal medulla it was lower than in total kidney (p = 0,002). There was no significant difference in NAP-22 mRNA expression level between renal medulla and total kidney (p = 0,011). There were no significant interstrain differences in the animal groups either in the levels of MARCKS mRNA expression in renal cortex (p = 0,872), in renal medulla (p = 0,024) or in total kidney (p = 0,520). Neither there were differences in the levels of NAP-22 mRNA expression in cortex (p = 0,028), in medulla (p = 0,028) and in total kidney (p = 0,978).Conclusions. In both SHR and WKY rat strains, the level of MARCKS and NAP-22 mRNA expression in cortical and medullary kidney layers is different, in WKY rats these differences are less pronounced. At the same time, interstrain differences in NAP-22 and MARCKS mRNA expression levels in cortical, medullary layers and in total kidney of SHR and WKY rats were not found.