Introduction: Breast cancer during pregnancy presents a rare yet clinically challenging scenario due to limited therapeutic options that ensure maternal–fetal safety. The lack of experimental models further hinders innovative approaches. This study introduces an original murine model of gestational breast cancer to assess the toxicological profile of a nanocomposite—AuPLU/AlClPc—comprising gold nanoparticles stabilized with Pluronic F127 and conjugated with aluminum chloride phthalocyanine, a photosensitizer designed for photodynamic therapy (PDT). Methodology: Pregnant BALB/c mice were divided into three groups: healthy controls (HC), tumor-bearing treated with PBS (TC), and tumor-bearing treated with AuPLU/AlClPc (TN). On gestational day E10.5, TC and TN were orthotopically transplanted with 4T1 mammary carcinoma cells, while HC remained tumor-free. On E17.5, TN received intravenous AuPLU/AlClPc and TC received PBS. Euthanasia occurred 24 h later. All procedures complied with institutional animal care guidelines and were approved by CEUA-UnB (protocol code 23106.115956/2022-46). Maternal health was assessed by body weight, liver/kidney biochemistry, hematology, and organ analysis. Results: TN animals exhibited leukocytosis (6.9 × 103/μL) with granulocyte predominance (47.5%) compared to HC (24%) and TC (21%). Platelet counts were reduced in tumor-bearing groups (TC: 429 × 103/μL; TN: 334 × 103/μL) versus HC (597 × 103/μL). A slight increase in urea was observed in TN (85.7 mg/dL) compared to HC (55 mg/dL). No significant differences were found in fetal weight or number. Other hematological and biochemical parameters remained unchanged. Conclusions: AuPLU/AlClPc induced mild immune modulation without evidence of maternal or fetal toxicity. Reproductive parameters remained preserved, supporting their potential for safe application in late pregnancy. The proposed model represents a methodological innovation for preclinical oncogynecological research.
Author Contributions
Conceptualization, L.R.A.; methodology, L.S.d.L.B.; validation, L.S.d.L.B., L.S.A., G.T., L.V. and A.B.S.S.; formal analysis and investigation, L.R.A., L.S.d.L.B., L.S.A., G.T. and L.V.; resources, L.R.A. and M.A.G.S.; data curation, L.R.A. and L.S.d.L.B.; writing-original draft preparation, L.S.d.L.B.; writing—review and editing, L.R.A. and L.S.d.L.B.; visualization, L.S.d.L.B.; supervision, L.R.A.; project administration and funding acquisition, L.R.A. All authors have read and agreed to the published version of the manuscript.
Funding
This research was funded by the Foundation for Research Support of the Federal District (FAPDF), grant number 00193-00001735/2022-18.
Institutional Review Board Statement
The animal study protocol was approved by the Animal Research Ethics Committee guidelines of the University of Brasilia (CEUA-UnB; protocol code 23106.115956/2022-46; date of approval: 18 June 2024).
Informed Consent Statement
Not applicable.
Data Availability Statement
The data presented in this study are available from the corresponding author upon reasonable request.
Conflicts of Interest
The authors declare no conflict of interest.
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