Human testicular mast cells contain tryptase: increased mast cell number and altered distribution in the testes of infertile men

Objective: To determine whether human testicular mast cells contain the pot ent fibroblast growth Factor tryptase and to examine changes in mast cell m orphology and intratesticular distribution in testes with normal spermatoge nesis versus abnormal spermatogenesis. Design: Retrospective evaluation of testicular biopsies with the use of imm unohistochemistry, morphometry, and electron microscopy. Setting: University research and clinical institutes. Patient(s): Infertile men (total of 24) with severe hypospermatogenesis, ge rm cell arrest syndrome, or Sertoli cell only syndrome, and men without pat hologies. Intervention(s): Diagnostic testicular biopsy. Main Outcome Measure(s): Location, number, and distribution of testicular m ast cells. Result(s): All groups showed tryptase-positive mast cells. In specimens wit h normal spermatogenesis, mast cells were round and located mainly in the i nterstitial spaces close to Leydig cells. In germ cell arrest syndrome, a 2 -fold increase was evident, and in Sertoli cell only syndrome, a >3-fold in crease of tryptase-immunoreactive mast cells became evident. Moreover, ther e was a statistically significant shift of the cells from the interstitium to the tubular walls in Sertoli cell only syndrome and germ cell arrest syn drome. Mast cells in specimens of Sertoli cell only syndrome and germ cell arrest syndrome were heterogeneous, with rounded or elongated shapes and si gns of degranulation. The thickness of the tubular walls was doubled in spe cimens of germ cell arrest syndrome and Sertoli cell only syndrome in compa rison with normal specimens, and this increase was positively correlated wi th the number of mast cells in these patients. Conclusion(s): Our results suggest that mast cell products, including the p otent fibroblast growth factor tryptase, are involved in the thickening of the tubular wall and other changes in infertile testes. (C) 2000 by America n Society fur Reproductive Medicine.