Enhanced monocyte adherence to thoracic aortae from rats with two forms of experimental hypertension

To extend our previous observation that thoracic aortae from rats with spontaneous hypertension (SHR) bind monocytoid cells with enhanced avidity, we isolated thoracic aortae from two different forms of rodent hypertension: Dahl salt-sensitive (Dahl-S) rats fed a high salt diet and Sprague-Dawley (S-D) rats fed a fructose-enriched diet. Blood pressure was determined 14 days after feeding normal chow or chow containing 8% NaCl to Dahl-S and Dahl salt-resistant (Dahl-R) rats, and either chow or a fructose-enriched diet to S-D and Fischer 344 (F-344) rats. Blood pressure was similar in Dahl-S and Dahl-R rats on the chow diet, but higher in Dahl-S rats in response to the 8% NaCl diet (188 ± 7 v 137 ± 3 mm Hg, P< .001). Blood pressure also increased when S-D rats consumed fructose as compared with chow (149 ± 4 v 128 ± 2, P< .05), whereas blood pressure did not change with diet in F-344. Thoracic aortae were removed from rats in each experimental group, and their ability to bind murine monocytoid cells quantified. Measurements of monocyte binding were performed on one experimental and one control rat simultaneously, and results presented as the ratio of cells bound by thoracic aortae from the experimental compared with the control rat. With this approach, the ratio of monocyte binding (8% NaCl/chow) was increased in Dahl-S versus Dahl-R rats (1.7 ± 0.1 v 1.3 ± 0.1, P< .05), as well as in S-D as compared with F-344 rats (1.7 ± 0.2 v 1.1 ± 0.1, P< .05). These results provide evidence that hypertension in Dahl-S and fructose-fed S-D rats was associated with changes in the endothelium that favor atherogenesis.