Congenic Strains for the Blood Pressure Quantitative Trait Locus on Rat Chromosome 2

Abstract

Abstract A quantitative trait locus (QTL) for blood pressure was previously detected by linkage analysis in a region of rat chromosome 2 using segregating populations derived from crosses of the Dahl salt-sensitive (Dahl S) rat with rats of the Wistar-Kyoto (WKY) strain or Milan normotensive strain (MNS). Two congenic strains, S.WKY-D2N35/ Nep and S.MNS- Adh /D2Mit5, have been constructed by replacing a region of chromosome 2 of the Dahl S rat with the homologous region (ie, low blood pressure QTL allele) of either the WKY or MNS rat, respectively. Systolic pressures of congenic strains S.WKY-D2N35/ Nep and S.MNS- Adh /D2Mit5 fed a 2% NaCl diet for 24 days were 44±4.6 and 29±4.5 mm Hg lower, respectively, than that of the comparably treated Dahl S rats. The differences between congenic and Dahl S rats in blood pressure were highly significant ( P <.001) and were corroborated by significantly ( P <.001) lower ratio of heart weight to body weight in the congenic strains compared with Dahl S rats. The data from two congenic strains combined unequivocally establish the existence of a blood pressure QTL on rat chromosome 2.