GLYCOCONJUGATE PROFILING IN TISSUES FROM HEALTHY, POLYENDOCRINE METABOLIC OVARIAN SYNDROME, AND CANNABIDIOL-TREATED RAT MODELS USING QUANTUM DOTS

In polyendocrine metabolic ovarian syndrome (PMOS), serum carbohydrate levels, including mannose, are elevated, highlighting its potential as a biomarker of insulin resistance (IR). Cannabidiol (CBD) may contribute to the treatment of IR by acting on cannabinoid receptors (CB2), which are also expressed in ovarian cells. However, alterations in carbohydrate profiles, particularly in ovarian tissues under PMOS conditions, remain incompletely understood. Cell and tissue glycophenotype can be assessed using fluorescent nanoprobes, such as quantum dots (QDs) conjugated with mannose-binding lectin (MBL), a calcium-dependent protein with high affinity for mannose-containing glycans. This study employed QD-MBL conjugates to investigate the glycoconjugate profile in ovarian tissues from a rat model of PMOS treated and untreated with CBD nanoemulsion. QD-MBL conjugates were prepared using an adsorption-based strategy. Forty Wistar rats (Animal Ethics Committee Approval N^o 0057/2025) were divided into four groups: control, PMOS, and PMOS treated with 5% and 10% CBD in nanoemulsion. PMOS was induced by oral administration of letrozole (1 mg/kg) for 21 days. CBD-treated groups received treatment for 7 days (0.125 mL/kg body weight), while control and PMOS groups received saline. Afterwards, rats were anesthetized and euthanized, and ovaries were collected for fixation, processing, and paraffin embedding for histological slide preparation. For QD-MBL labeling, tissue sections were deparaffinized, rehydrated, treated with trypsin-EDTA, and washed with PBS. Tissue sections were then incubated with QD-MBL conjugates (1:1 v/v in PBS-Ca²⁺) in a humid chamber for 1 h at 4 °C. After PBS washing, samples were analyzed by fluorescence microscopy. Results showed increased labeling in follicular cells of granulosa and theca layers, also in growing, mature, and atretic follicles in the PMOS group. In contrast, follicular cells within ovarian cysts showed no noteworthy labeling. CBD-treated groups exhibited markedly reduced labeling in growing and mature follicles, displaying patterns comparable to control. These findings suggest altered mannose-rich glycan levels among ovarian tissues. In conclusion, QD-MBL conjugate demonstrated potential for investigating glycophenotype changes in ovarian tissues and revealed the effect of CBD nanoemulsion in modulating MBL-binding glycan patterns in ovarian follicular cells under PMOS conditions.