Immunomodulatory Effects of Dietary Potassium Perfluorooctane Sulfonate (PFOS) Exposure in Adult Sprague-Dawley Rats
Bibliographic record
Abstract
Perfluorooctanesulfonate (PFOS) is a stable and environmentally persistent metabolic or degradation product of perfluorooctanyl compounds that were manufactured for a variety of industrial and consumer applications. PFOS itself was sold for use as a surfactant. The structurally related contaminants perfluorooctanoic acid (PFOA), perfluorodecanoic acid (PFDA), and N-ethyl perfluorooctane sulfonamide (N-EtPFOSA) were shown to suppress immune responses in laboratory rodents. Relatively low doses of PFOS were found to be immunosuppressive in mice. To assess effects of PFOS on the rat immune system at doses known to alter hepatic function, changes in the morphology and function of immune tissues and cells were measured in adult rats exposed to PFOS in their diet for 28 d at levels ranging from 2 to 100 mg PFOS/kg diet (corresponding to approximately 0.14 to 7.58 mg/kg body weight [bw]/d) and compared to those receiving control diet. Body weight reductions were significant in male and female rats exposed to 50 and 100 mg PFOS/kg diet. Liver/body weight was significantly increased in females exposed to 2 mg PFOS/kg diet and in males exposed to 20 mg PFOS/kg diet. Female rats exposed to 100 mg PFOS/kg diet exhibited a significant increase in spleen weight relative to body weight; these changes lacked a histologic correlate and were not observed in males. While thymus weights relative to body weights were not affected, numbers of apoptotic lymphocytes rose in thymus with increasing dietary PFOS. There was a significant dose-related increase in total peripheral blood lymphocyte numbers in female but not male rats. In both genders the percentages of cells within lymphocyte subclasses were altered. There was a significant trend toward increasing T and T-helper (Th) cells and decreasing B cells with higher PFOS dose. Serum total immunoglobulin (Ig) G1 levels were significantly reduced in males exposed to 2 and 20 mg PFOS/kg diet. The ability of male and female rats to mount delayed-type hypersensitivity (DTH) responses to the T-cell-dependent antigen keyhole limpet hemocyanin (KLH) was not altered by PFOS. There was a significant trend toward elevated KLH-specific IgG in serum from male rats exposed to increasing levels of PFOS in diet. Splenic T- and B-cell proliferation in response to ex vivo mitogen exposure was unaffected by exposure to dietary PFOS. In conclusion, changes in immune parameters in rat did not manifest as functional alterations in response to immune challenge with KLH and may be secondary to hepatic-mediated effects of PFOS in this model.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
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 teacher head, 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".