Concern about the reproductive potential of long-term survivors of acu
te lymphoblastic leukaemia (ALL) prompted an investigation into the im
pact of the disease on spermatogenic cells. Using rats as a model, his
tological, immunocytochemical and electron microscopic analysis was ap
plied to investigate changes in the seminiferous epithelium In rats tr
ansplanted with leukaemic cells at early puberty, degenerate primary s
permatocytes and spermatids were prevalent within stage VIII tubules.
Electron microscopically, step 8 spermatids showed acrosomal abnormali
ties and nuclear contour distortion. In the distorted step 9 spermatid
s, the microtubules of the manchette were abnormally oriented or defic
ient. Antitubulin antibody staining was reduced in elongating spermati
ds in the group transplanted with leukaemic cells at early puberty but
was not observed in the older leukaemic group. Step 13 spermatids sho
wed extracted chromatin and degenerate step 19 spermatids were occasio
nally found. Similar but less severe changes were seen in the group of
rats transplanted with leukaemic cells at late puberty. We conclude t
hat germinal cell damage induced by ALL is dependent on the developmen
tal maturity of the seminiferous epithelium. The present findings are
of particular importance when interpreting the impact of anticancer ch
emotherapeutics on germinal cells in patients with ALL.