Summary
This in vivo rat study examined Cr(VI)-induced damage to the endocrine pancreas and tested whether Hypericum perforatum (St. John’s wort) extract mitigated those effects. Wistar rats received potassium dichromate (K2Cr2O7) dissolved in distilled water at 75 mg/L for three months; control animals received distilled water only. Cr(VI) caused significant reductions in islet of Langerhans size (p less than 0.0001), interlobular and intralobular edema, cytoplasmic vacuolisation, pycnotic nuclei, and elevated Bax/Bcl2 ratios indicating apoptosis. Blood glucose was elevated in Cr(VI)-exposed animals. Structural recovery was observed when Hypericum perforatum extract was administered after cessation of chromium exposure. The paper is the first study from this research group specifically characterising Cr(VI) effects on the endocrine pancreas and is cited on the hexavalent chromium wiki page as evidence for pancreatic endocrine toxicity.
Key numbers
| Measurement | Cr group | CrH group | Cr2 group | CrH2 group | Control | Source location |
|---|---|---|---|---|---|---|
| Islet of Langerhans perimeter (microm) | significantly reduced vs. control (p less than 0.0001) | significantly reduced vs. control (p less than 0.0001) | significantly reduced vs. control (p less than 0.0001); no recovery | approached control values | reference | Figure 5 |
| Pancreatic edema score | 3 (marked) | 1 (mild) | 3 (marked) | 0 (absent) | 0 (absent) | Table 1 |
| Bax gene expression | low, comparable to control | low | pronounced overexpression (p less than 0.001 vs. all groups) | modest increase vs. control | low baseline | Figure 9 |
| Bcl2 gene expression | low | low | pronounced overexpression (p less than 0.001 vs. all groups) | modest increase vs. control | low baseline | Figure 9 |
chromium (Cr) dose: 75 mg/L potassium dichromate in drinking water (3 months). The EPA LOAEL for Cr(VI) is noted in this paper as 25 mg/L; 75 mg/L was selected to reliably produce toxic effects in the model. Sample size: n = 6 per group.
Evidence Fitness
Context only. This is an animal study at a dose (75 mg/L potassium dichromate, far above typical human water exposure levels) designed to produce detectable toxicity in a 3-month rat model. It establishes the endocrine pancreas as a Cr(VI) target organ and characterises the apoptotic pathway through Bax/Bcl2, but does not translate directly to dietary exposure estimates or food occurrence data. Findings are relevant mechanistic context for the toxicology section of the hexavalent chromium wiki page.
Methods (brief)
Thirty adult male Wistar rats (220 to 240 g), 5 groups of 6. Cr source: potassium dichromate from Sigma-Aldrich (99% purity or higher), dissolved to 75 mg/L in distilled water. Tissue: pancreas collected at euthanasia (ketamine/xylazine overdose). Histology: H.E. staining, light microscopy; islet perimeter measured with imaging software; edema scored 0 to 3; Bax and Bcl2 gene expression by qRT-PCR (normalised to reference gene). Blood glucose measurement method not described beyond “blood glucose level analysis.” LOD/LOQ, CRM and recovery are not reported for the gene expression assay; the histological scoring was performed by two blinded observers for the reproductive paper from the same group but blinding is not stated for histology in this paper.
Implications
- Certification: no direct application; Cr(VI) pancreatic endocrine toxicity is mechanistic context for the ingestion hazard framing.
- Courses: provides an organ-level example of Cr(VI) toxicity beyond the well-known lung cancer endpoint.
- App: no contamination_profile data; not applicable.
- Microbiome: not applicable.
Provenance notes
Open access, CC BY 4.0. Senior authors Marc S and Boldura OM contributed equally. Institution: Faculty of Veterinary Medicine, University of Life Sciences “King Mihai I” from Timisoara, Romania. Ethical approval noted (No. 60/23.07.2019 from Banat University of Agricultural Sciences and Veterinary Medicine). No retraction or correction flags at time of ingest. See Chromium, Hexavalent for the page this source informs.
Update history
No substantive edit history is available in this build. The full commit record is available in git.