[Expression of cytokines and their receptors in left ventricular hypertrophy in TGR(mRen2)27 rats].

Variations in the expression of cytokines from the interleukin-6 (IL-6) family: ciliary neurotrophic factor (CNTF), leukaemia inhibitory factor (LIF), and cardiotrophin 1 (CT-1) were studied during cardiac remodelling leading to left ventricular hypertrophy (LVH) in TGR(mRen2)27 rats at the age of 8 and 20 weeks. The cytokines mRNA levels within the free wall of the left ventricle were measured by semi-quantitative RT-PCR standardised with 18S. They were compared between heterozygous rats for the mRen2 transgene (TG+/-) and control rats (TG-/-). No significant difference was observed between results obtained at 8 and 20 weeks of age. At 20 weeks of age, TGR(mRen2)27 rats showed higher levels of mRNA LIF and IL-6 respectively by 52 and 55% compared to the control rats [LIF TG+/-: 3.17 +/- 0.21, TG-/-: 2.09 +/- 0.03; p < 0.001; n = 5; and IL-6 TG+/-: 1.53 +/- 0.13; TG-/-: 0.99 +/- 0.17; p < 0.05; n = 5]. By contrast, no variation of mRNAs levels of CT-1 and gp 130 genes was observed between control and transgenic rats. Concerning the cytokine receptors, the levels of mRNA for IL-6R did not vary while those of receptor subunits LIFR and CNTFR were decreased respectively by 48 and 42% in transgenic rats vs controls [LIFR TG+/-: 0.48 +/- 0.01; TG-/-: 0.92 +/- 0.08 p < 0.001; n = 5; and CNTFR TG+/-: 1.07 +/- 0.08; TG-/-: 1.85 +/- 0.18; p < 0.01; n = 5]. Therefore, these results show a specific pattern of activation of the cytokines pathway in the LVH of the TGR(mRen2)27 rat.