Evaluation of heat shock protein 70 expression in renal parenchyma subjected to shockwave lithotripsy

In this experimental study in a rabbit model, renal parenchymal heat shock protein 70 (hsp70) levels were assessed in an attempt to evaluate the traumatic effects of high-energy shockwaves (HESW), which have been found to induce transient ischemia during the procedure.

Eighteen white New Zealand rabbits, each weighing 3 to 5 kg, were included in the study. The animals were divided into three groups, and various numbers of shockwaves (1000, 1500, or 2000) were applied to the same kidney of all animals under fluoroscopic localization with a Stonelith V5 lithotripter. Untreated contralateral kidneys were evaluated as controls. Following HESW application, the treated and untreated kidneys were removed surgically after 24 hours or 7 days. Tissue hsp70 levels were assessed by an immunohistochemistry method.

During early follow-up (24 hours), both treated and untreated kidneys demonstrated moderate to severe hsp70 positivity. The number of positive tubules increased as the number of shockwaves increased, and positivity became more evident, possibly because of a higher degree of tissue damage. Contralateral kidneys demonstrated a limited degree of hsp70 positivity, although it was not as evident as in the treated kidneys. Assessment of tissue hsp70 levels during late follow-up (7 days) demonstrated moderate or limited degrees of positivity in the treated kidneys. Limited or no positivity could be demonstrated in the untreated kidneys during this period.

Taking the known traumatic effects of HESW and the results of this study into account, the increasing positivity of hsp70 in parallel with the increasing number of shockwaves led us to think about a possible limited degree of ischemia induced by this procedure, as the traumatic effects of HESW were pronounced, as judged by tissue hsp70 positivity.