Induction of metallothionein synthesis with preservation of testicular function in rats following long term renal transplantation

Metallothionein (MT), as an acute phase or stress-response protein and free radical scavenger, is related to inflammation and cellular protection from oxidative damage. In order to evaluate long-term testicular damage and the role of MT following renal transplant, nine allogenic (Fisher 344 --> Lewi s) and seven isogenic (Lewis --> Lewis) renal transplants were performed an d the recipient rats were followed for 140 days when allografts develop chr onic transplant rejection. Testicular weight, light microscopic morphology, and lactate dehydrogenase-X enzyme activity were assessed. Testicular MT w as determined by Cd-heme assay, and was localized immunocytochemically usin g a polyclonal rabbit antibody. No differences in testis weight, morphology , or LDH-X enzyme activity were found between allograft and isograft recipi ents. Testicular MT level was significantly increased in the testis of allo graft recipients. Testicular zinc (Zn) and copper (Cu) levels, but not iron (Fe) level. were significantly higher in testis with allograft kidney than that with isograft kidney. In addition, Cu/Zn ratio was also significantly high in the allograft group. However, the MT level did not show any signif icant correlation either with Cu and Zn alone or with Cu/Zn and Fe/Zn ratio s. These data suggest that allogenic stimuli may induce MT synthesis in the recipient testis. The increased MT level in an allograft may offer a prote ctive action from oxidative damage in the testis.