Assessment of germ-cell kinetics in the testes of patients with varicocele using image analysis of immunostained proliferating cell nuclear antigen.

OBJECTIVE

To examine the germ-cell kinetics of varicocele testis using proliferating cell nuclear antigen (PCNA) immunostaining and image cytometry to evaluate the staining intensity, and to compare the proliferative index (PI) of varicocele and normal testes.

PATIENTS AND METHODS

Fifty-six testicular biopsy specimens were taken from 28 patients with varicocele during high ligation. The specimens were fixed and embedded in paraffin, and sections immunostained using an anti-PCNA antibody. The PI was measured using an image analyser and expressed as the percentage of the total nuclear area stained positively with PCNA monoclonal antibody, assessed from > 20 seminiferous tubules. Sections stained with haematoxylin and eosin were used to determine Johnsen's score using conventional microscopy. Normal control testicular biopsies were obtained from subjects undergoing vasectomy.

RESULTS

In patients with varicocele, both testes had a significantly lower PI than normal testes; the mean (SD) PI of the right and left testes was 11.3% (4.1) and 11.3% (4.8), respectively, and the PI of normal testes was 21.7% (3.1). There was no significant correlation between PI and sperm concentration or Johnsen's score.

CONCLUSION

PI is useful for assessing germ-cell kinetics; in patients with varicocele both testes showed a deterioration in DNA synthesis, suggesting that reduced DNA synthesis is one of the causes of spermatogenic dysfunction in the varicocele testes.