A Game of Cat and Mouse: Xenografting of Testis Tissue From Domestic Kittens Results in Complete Cat Spermatogenesis in a Mouse Host
Bibliographic record
Abstract
Loss of genetic diversity because of infertility or the premature death of valuable individuals is a significant problem in the conservation of rare and endangered felid species, as well as in the maintenance of lines of cats used to study inherited feline and human disease. Attempts to overcome loss of genetic diversity have focused on freezing sperm; however, sperm cannot be collected from immature males. Previously, we reported completion of spermatogenesis in testis tissue from newborn pigs and goats grafted ectopically into host mice. The objective of this study was to extend the technique of testis tissue xenografting to the domestic cat as a model for felid species. Testes from 1- to 5-week-old domestic shorthaired kittens (n = 9) were cut into small fragments (about 0.5-1 mm3 each), and up to 8 fragments were grafted under the back skin of each castrated immunodeficient host mouse (n = 16). Histologic examination of the testis xenografts was performed between 5 and 54 weeks posttransplantation. At the time of grafting, the seminiferous cords of the donor testis tissue contained only immature Sertoli cells and gonocytes. At 14 weeks after grafting, tubular expansion was evidently caused by the proliferation of Sertoli cells and tubular lumen formation. By 18 weeks after transplantation, the seminiferous epithelium contained spermatocytes, and by 20 weeks, round spermatids were the most advanced types of germ cells. By 36 weeks after transplantation, xenografts of cat testis tissue had completed spermatogenesis. These results demonstrate the potential of xenografting to achieve full spermatogenesis in testis tissue from kittens. Therefore, sperm production in a mouse host can provide an alternative for germ line preservation from immature felids where sperm cryopreservation is not an option.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".