Evaluating the QileX-RhE skin corrosion test for chemical subcategorization in accordance with OECD TG 431

Skin corrosion testing is integral to evaluating the potential harm posed by chemicals, impacting regulatory decisions on safety, transportation, and labeling. Traditional animal testing methods are giving way to in vitro alternatives, such as reconstructed human epidermis (RhE) models, aligning with evolving ethical standards. This study evaluates the QileX-RhE test system's performance for chemical subcategorization within the OECD TG 431 framework. Results demonstrate its ability to differentiate subcategories, accurately predicting 83% of UN GHS Category 1A and 73% of UN GHS Category 1B/1C chemicals with 100% sensitivity in corrosive prediction. Additionally, this study provides a comprehensive assessment of the test method's performance by employing nuanced parameters such as positive predictive value (PPV), negative predictive value (NPV), post-test odds and likelihood rations, offering valuable insights into the applicability and effectiveness of the QileX-RhE test method.

The chemokine CCL5 induces CCR1-mediated hyperalgesia in mice inoculated with NCTC 2472 tumoral cells

Although the expression of the chemokine receptor CCR1 has been demonstrated in several structures related to nociception, supporting the nociceptive role of chemokines able to activate it, the involvement of CCR1 in neoplastic pain has not been previously assessed. We have assayed the effects of a CCR1 antagonist, J113863, in two murine models of neoplastic hyperalgesia based on the intratibial injection of either NCTC 2472 fibrosarcoma cells, able to induce osteolytic bone injury, or B16-F10 melanoma cells, associated to mixed osteolytic/osteoblastic bone pathological features. The systemic administration of J113863 inhibited thermal and mechanical hyperalgesia but not mechanical allodynia in mice inoculated with NCTC 2472 cells. Moreover, in these mice, thermal hyperalgesia was counteracted following the peritumoral (10-30μg) but not spinal (3-5μg) administration of J113863. In contrast, hyperalgesia and allodynia measured in mice inoculated with B16-F10 cells remained unaffected after the administration of J113863. The inoculation of tumoral cells did not modify the levels of CCL3 at tumor or spinal cord. In contrast, although the concentration of CCL5 remained unmodified in mice inoculated with B16-F10 cells, increased levels of this chemokine were measured in tumor-bearing limbs, but not the spinal cord, of mice inoculated with NCTC 2472 cells. Increased levels of CCL5 were also found following the incubation of NCTC 2472, but not B16-F10, cells in the corresponding culture medium. The intraplantar injection of CCL5 (0.5ng) to naïve mice evoked thermal hyperalgesia prevented by the coadministration of J113863 or the CCR5 antagonist, d-Ala-peptide T-amide (DAPTA), demonstrating that CCL5 can induce thermal hyperalgesia in mice through the activation of CCR1 or CCR5. However, contrasting with the inhibitory effect evoked by J113863, the systemic administration of DAPTA did not prevent tumoral hyperalgesia. Finally, the peritumoral administration of an anti-CCL5 antibody completely inhibited thermal hyperalgesia evoked by the inoculation of NCTC 2472 cells.

In vivo behavior of complete human oral mucosa equivalents: characterization in athymic mice

BACKGROUND AND OBJECTIVE

The interest in tissue engineering as a way to achieve repair of damaged body tissues has led to the carrying out of many studies whose results point to the potential effectiveness of these methods. In a previous study, we reported the obtaining of complete autologous oral mucosa equivalents (CAOMEs), characterized by oral immature keratinocytes and stem cells on an autologous plasma and fibroblast scaffold. The purpose of this study is to show their behavior in vivo, by using them as free grafts in experimental animals, and to demonstrate their potential capacity to regenerate oral mucosa.

MATERIAL AND METHODS

We engineered CAOMEs, as previously described. All CAOMEs thus obtained were used as free grafts in nu/nu mice. To assess their evolution in vivo, we studied their histological and immunohistochemical features by using AE1/AE3 pancytokeratin, the 5/6 cytokeratin pair, cytokeratin 13, laminin 5, collagen IV, vimentin, p-63 and Ki-67, at 7, 14 and 21 d.

RESULTS

The structure became progressively closer to that of oral mucosa samples. Cytokeratin 5/6 staining became increasingly intense in the basal and suprabasal layers, and cytokeratin 13 was exclusively positive in the superficial layers. The basal membrane was completed in 21 d. Vimentin showed a correct formation of the chorion. The increasingly positive staining of p-63 and Ki-67 indicated that the regeneration process was taking place.

CONCLUSION

The present study shows the potential regenerative capacity of the CAOMEs by their ability to reach maturity similar to that seen in oral mucosa.