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.