EFFECTS OF 7 DAYS OF GALACTOSE FEEDING AND ALDOSE REDUCTASE INHIBITION ON MAST-CELLS AND VESSEL MORPHOMETRY IN RAT SCIATIC-NERVE

The association between mast cells and vessel morphometry in sciatic n erve was examined after seven days in animals fed a diet of 40% D-gala ctose and compared to control rats and to galactose-fed animals treate d with the aldose reductase inhibitor, Tolrestat Electron microscopy r evealed an increase in the total number of mast cells and the number o f degranulated mast cells in galactose-fed animals (7.8 +/- 2.9; 2.6 /- 2.9; mean +/- SD) compared to controls (4.6 +/- 2.1, degranulated m ast cells were not seen in any control nerves) and Tolrestat-treated, galactose-fed animals (4.4 +/- 2.5; 0.1 +/- 0.4). Although no signific ant differences were noted in the numbers of vessels between the three groups, an index of vasoconstriction was significantly increased in t he galactose-fed animals (0.115 +/- 0.048; mean +/- SD) compared to co ntrols (0.068 +/- 0.011) and Tolrestat-treated, galactose-fed animals (0.075 +/- 0.020). These data suggest that mast cell degranulation is associated with the vascular constriction induced by seven days of gal actose intoxication and that both may be prevented by inhibiting aldos e reductase.