Tissue expression of TRPC3 and TRPC6 in hypertensive Munich Wistar Frömter rats showing proteinuria.

BACKGROUND We investigated whether alterations of transient receptor potential canonical (TRPC) channel expression may be observed in tissues from Munich Wistar Frömter (MWF) rats showing proteinuria compared to control Wistar rats. METHODS TRPC expression was investigated in tissue from MWF and Wistar rats using quantitative real time PCR, immunoblotting, and immunohistochemistry. RESULTS Compared to Wistar rats MWF rats showed significantly increased systolic blood pressure and significantly higher left ventricle weight (each p < 0.01). Quantitative real time PCR revealed that TRPC3 transcripts were significantly higher in kidney cortex from MWF rats compared to Wistar rats (p < 0.01). TRPC3 transcripts were not significantly different in kidney medulla nor in aorta from both groups (p = n.s.). Furthermore, TRPC6 transcripts were significantly lower in kidney cortex from MWF rats compared to Wistar rats (p < 0.001). Immunoblotting showed that TRPC3 channel protein expression was also significantly higher in kidney cortex from MWF rats compared to Wistar rats (p < 0.01). There was a significant correlation of TRPC3 mRNA and a specific marker for endothelium, von Willebrand factor (vWF; Spearman r = 0.564; p < 0.01). We observed a significant correlation between the TRPC3 transcripts to TRPC6 transcripts ratio in kidney cortex and urinary albumin excretion (Spearman r = 0.785, p < 0.001). CONCLUSION Altered TRPC expression pattern in kidney cortex is associated with kidney damage in MWF rats showing hypertension and albuminuria.