RenalLysozyme Levels inAnimals Developing "Sterile Pyelonephritis"

Theinduction ofsterile unilateral pyelonephritis inrats withheat-killed Proteus mirabilis cells isdescribed. Thelesions wereidentical tothose produced withviable bacteria. Lysozyme levels inbothkidneys ofrats developing unilateral sterile pyelonephritis underwent biphasic elevations similar tothose produced withviable bacteria. Intheinjected kidney, thefirst elevation, associated withthetrauma ofinjection, could beproduced byinjecting sterile saline. Thesecond elevation wasassociated withtheonset ofchronicity intheinjected kidney. Thenonmanipulated, contralateral kidney showed asimilar biphasic elevation, ofequal duration butof greater magnitude. Previous workinourlaboratory indicated that trauma toakidney causes anincrease initssolublelysozyme content (10). Thisobservation agrees with theresults ofHamdy(11), whodemonstrated thattraumacauseselevated levels ofsoluble lysozyme inpoultry tissue. However, inunilateral renal trauma, a simultaneous elevation ofthe soluble lysozyme content ofthecontralateral kidney wasalso observed whichwasofgreater magnitude thanandequalin duration tothat ofthe injured kidney (10). Furthermore, inratsdevelopingchronic, unilateral Proteus mirabilis-induced pyelonephritis (7), thelevels ofrenal lysozyme in bothkidneys exhibit asecond elevation withthe contralateral kidney showing thehigher lysozyme activity (10). Incidence ofinfection intheexperimentally uninfected kidney islow(7), andpathological indications ofinfection areabsent (10). Thesefindings donoteliminate thepossibility thatviable bacteria intheexperimentally uninfected kidney are responsible fortheobserved results. Toinvestigate this possibility andfurthermore toinvestigate the role oftheinflammatory response inthetissue destruction characteristic ofchronic pyelonephritis, a sterile pyelonephritis modelinduced with heat-killed bacteria hasbeendeveloped. This communication concerns thedescription ofthis modelandthelevels ofsoluble renal lysozyme in thekidneys ofratsdeveloping experimentally induced, sterile, unilateral, chronic pyelonephritis.