title: Heat-shock resistance in experimental cryptorchid testis of mice.
abstract: Cryptorchidism is commonly used for research on spermatogenesis. However, there are few comparative investigations about the strain differences in mice, especially in long-term experiments. In the present study, the authors demonstrate its specific dynamics in the MRL/MpJ mouse strain, and discuss the cause of strain differences. In the mouse strains A/J BALB/c, C3H/He, and C57BL/6, after 2 weeks of experimental cryptorchidism, the ratios of the cryptorchid testis weight against the intact one were 0.38+/-0.05, 0.43+/-0.05, 0.38+/- 0.02, and 0.44+/-0.14, respectively. On the other hand, in the MRL/MpJ strain it was shifted to 0.69+/-0.08. The details of this strain difference were compared by calculation of germ cells with the Sertoli cell index at 2 weeks after operation. The indices of spermatogonia in all strains were not significantly different; however, in MRL/MpJ mice remarkable numbers of late spermatocytes and round spermatids were detected. The decrease of the testis weight ratio was similar until 10 days in the C57BL/6 and MRL/MpJ strains, but continued in C57BL/6 until 21 days, whereas in MRL/MpJ mice it plateaued after 10 days. Northern blot analysis for heat shock protein 70-2 using total RNA prepared from the cryptorchid and intact testes at 2 weeks after operation revealed that the expression was decreased in the cryptorchid testis of C57BL/6, but not MRL/MpJ mice. The results suggested that heat-resistant germ cells were present in MRL/MpJ, originating possibly from the genetic background.
authors.affiliation: Laboratory of Experimental Animal Science, Department of Disease Control, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan. y-kon@vetmed.hokudai.ac.jp
authors.forename: Y
authors.initials: Y
authors.lastname: Kon
authors.forename: D
authors.initials: D
authors.lastname: Endoh
mesh_terms: D000818:Animals; D001835:Body Weight; D003456:Cryptorchidism / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D004195:Disease Models, Animal; D015870:Gene Expression; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics*; D018869:Heat-Shock Response; D008297:Male; D051379:Mice; D008805:Mice, Inbred A; D008807:Mice, Inbred BALB C; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D019463:Mice, Inbred MRL lpr; D009929:Organ Size; D012708:Sertoli Cells / Q000166:cytology; D013093:Spermatogonia / Q000166:cytology; D013737:Testis / Q000378:metabolism* / Q000473:pathology
chemical_list: D018840:HSP70 Heat-Shock Proteins; C490434:Hspa2 protein, mouse