Experimental diabetes-induced testicular damage in prepubertal rats.

Background: There has been a marked increase in the prevalence of childhood
and/or adolescent diabetes worldwide. Testicular dysfunction in adultonset
diabetes is well established, whereas the impact of early onset diabetes
on the functional development of the testis remains elusive. In the present
study we investigated early oxidative impairments and progressive histological
changes in streptozotocin (STZ)-induced diabetic prepubertal rat testis.
Methods: Testes were sampled from prepubertal rats injected with a single
bolus of STZ (90 mg/kg, i.p.) on Days 1, 3, 5, 7 and 14 after STZ injection for
quantitation of testicular oxidative stress parameters in isolated subcellular
fractions and mitochondrial and microsomal functional efficiency, as well as
at weekly intervals over a period of 8 weeks for histological and flow cytometry
analyses.
Results: Prepubertal diabetic rats were severely hyperglycemic with reduced
testes size. At the subcellular level, a progressive increase in oxidative stress
parameters was discernible in the cytosolic and microsomal compartments
from Day 1 after STZ, together with decreased antioxidant defenses. Surprisingly,
tissue ascorbate and free catalytic iron levels were notably increased in
diabetic rat testis. Mitochondrial dysfunction was manifested from Day 5, as
evidenced by a reduction in electron transport activity. Histologically, tissue
sections showed distorted seminiferous tubules and extensive cell vacuolization
with progressive disappearance of spermatids in the lumen by Week 7
after STZ injection, observations that were consistent with flow cytometry
data.
Conclusions: Herein we provide evidence that the onset of diabetes brings
about oxidative changes at the subcellular level that cumulatively affect the
functional growth of testes.