MORPHOLOGICAL AND MORPHOMETRIC STUDY OF EARLY CHANGES IN THE AGING GOLDEN-HAMSTER TESTIS

The histological and morphometric features of the aged golden hamster testis were examined and compared with those of adult animals. Three a ge groups (6, 12 and 18 months) were studied by light microscopy, and testosterone levels were determined. The observations showed a progres sive involution of the seminiferous tubules, beginning to be perceptib le at 12 months with slight hypospermatogenesis and desquamation. In 1 8-month-old specimens degeneration was more significant and histopatho logical lesions could be classified on a 6-point scale, ranging from s light hypospermatogenesis to absence of germ cells. These involutive c hanges were not homogeneously distributed in the testis; affected tubu les close to seeming normal ones were present. The morphometric result s pointed to a progressive diminution, in the 3 age groups, in vas def erens spermatozoa, pachytene spermatocytes, and Sertoli and Leydig cel ls (the latter significantly diminished only in the 18-month-old group ). For morphometric purposes a 7-point scale of tubule degeneration wa s used, showing a significant increase, with age, in the presence of m ore degenerated tubule stages. Several correlations were found between the morphometric variables, outlining existing relations between age and the associated diminution of several testis cell types, and lumen diameter. No significant differences were found between groups in seru m testosterone levels. In conclusion, histological changes related to age are evident in 18-month-old animals, while at 12 months a diminuti on in germ cell numbers and sperm production is detectable.