Significant IgG-immunoreactivity of the spermatogonia of the germ cell-depleted testis after busulfan treatment.
Busulfan kills spermatogonia with the exception of a few that are attached to the basal membrane of the seminiferous epithelium. In mice, these remaining spermatogonia reacted strongly to a goat anti-mouse IgG antibody. Spermatogonia in untreated testes rarely showed the same reactivity. Testicular IgG levels are normally minimal but increase markedly, 4 weeks after busulfan treatment before peaking at week 6. Laser scanning cytometry analysis of control and busulfan-treated testicular cells showed busulfan treatment increased the frequency of cells that were positive for not only IgG (from 0.67+/-0.29 to 16.5+/-3.8%) but also for alpha6-integrin, beta1-integrin, GFR(-1 and/or Ret. Thus, an enrichment in putative male stem cells correlates with appearance of IgG expression. Confocal microscopy revealed busulfan-treated cells contained both IgG and GFRalpha-1, and that the initial surface IgG became intracellular in the weeks following busulfan treatment. The basement membranes of the seminiferous tubules were compromised by busulfan treatment as the mRNA expression profiles of various adhesion molecules in the basement membranes were altered and electron microscopy revealed severe damage. Serum IgG levels increased in a manner corresponding with the increase in testicular IgG levels. Thus, it appears that in the busulfan-treated testis, small breaches of the blood-testis barrier leak IgG that is then taken up by a significant number of spermatogonia. When the busulfan-resistant germ cells were transferred into recipient germ cell-depleted testes, they settled and repopulated the recipient testes. Thus, the IgG-bearing cells observed after busulfan treatment may be putative spermatogonial stem cells.
Choi
Yun-Jung
YJ
Department of Dairy Science, Division of Animal Science and Technology, College of Agriculture and Life Science, Gyeongsang National University, Jinju, GyeongNam 660-701, Republic of Korea.
Song
Hyuk
H
Kwon
Deug-Nam
DN
Cho
Seong-Keun
SK
Kang
Sung-Jo
SJ
Yoe
Sung-Moon
SM
Kim
Heung-Cheol
HC
Lee
Hoon-Taek
HT
Park
Chankyu
C
Kim
Jin-Hoi
JH
D000477:Alkylating Agents / Q000494:pharmacology*; D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000276:immunology; D002066:Busulfan / Q000494:pharmacology*; D016923:Cell Death / Q000187:drug effects; D006041:Goats; D007074:Immunoglobulin G / Q000276:immunology*; D039503:Integrin alpha6; D019012:Integrin beta1; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D008854:Microscopy, Electron; D012313:RNA / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013093:Spermatogonia / Q000276:immunology* / Q000637:transplantation; D013094:Spermatozoa / Q000737:chemistry / Q000187:drug effects* / Q000637:transplantation; D013737:Testis / Q000737:chemistry / Q000166:cytology* / Q000187:drug effects
D000477:Alkylating Agents; D000888:Antibodies, Anti-Idiotypic; D007074:Immunoglobulin G; D039503:Integrin alpha6; D019012:Integrin beta1; D012313:RNA; D002066:Busulfan