Modification of the Effects of Hypertension on Lysosomes and Connective Tissue in the Rat Aorta

Abstract

The relationship of Iysosomes to the vascular effects of hypertension and the possible modification of these effects by anti-inflammatory agents (methylprednisolone and aspirin), vitamin E, and estrogen were studied. Each of these agents was given to a group of hypertensive rats; untreated hypertensive rats and normotensive rats served as controls. Vessel wall morphology and dimensions of aortas from hypertensive rats were unaffected by treatment. Usual connective tissue accumulations seen in hypertensive vessels were suppressed to normotensive levels in the methylprednisolone- and estrogen-treated hypertensive groups. Two lysosomal enzymes, acid phosphatase and N -acetyl-β- d -glucosaminidase (NAGA), increased over normal levels in hypertensive vessels from 1.03 ± 0.08 ( SE ) to 2.04 ± 0.19 µmoles/aortic pair hour -1 and from 1.10 ± 0.24 to 4.57 ± 0.38 µmoles/aortic pair hour -1 for the respective enzymes. Normal enzyme levels in estrogen-treated hypertensive rats (1.14 ± 0.15 µmoles/aortic pair hour -1 for acid phosphatase and 2.04 ± 0.44 µmoles/aortic pair hour -1 for NAGA) and intermediate levels in methylprednisolone-treated hypertensive rats (1.35 ± 0.10 µmoles/ aortic pair hour -1 for acid phosphatase and 2.48 ± 0.54 µmoles/aortic pair hour -1 for NAGA) were found. Other treated groups showed the usual elevations associated with hypertension. These group differences were also seen after cytochemical staining for lysosomal acid phosphatase and NAGA. The parallel changes in aortic connective tissue and lysosomal enzymes in hypertension and their modification by two drugs suggest that these events are related.