Dados do Trabalho

Title

In vitro exposure of cannabidiol impairs expansion of cumulus cells during oocyte maturation: outcomes using bovine model.

Objective

Oocyte maturation is a crucial process involving complex molecular signaling pathways that significantly impact successful fertilization, embryonic development, and implantation in both humans and animals. Environmental factors such as lifestyle choices, dietary habits, and the use of legal or illegal drugs can easily influence these processes, leading to reduced oocyte, sperm, and embryo quality. Scientists in reproductive medicine have expressed interest in the potential role of cannabidiol (CBD), a cannabis- derived compound known for its ability to modulate hormonal processes and reduce inflammation. Several studies have investigated the effects of CBD on different aspects of the reproductive process, aiming to understand its influence on oocyte quality and overall fertility. Some evidence suggests that CBD may interact with the endocannabinoid system, which plays a crucial role in regulating reproductive function. However, further research is required to fully elucidate the specific mechanisms by which CBD affects oocyte maturation and reproductive outcomes. This study aimed to explore the effects of CBD during the in vitro maturation of oocytes using cattle as a model to assess potential future implications.

Methods

Bovine ovaries were collected from the slaughterhouse and transported to the laboratory in a thermal container at 37 °C in saline solution (0.9% NaCl). Antral follicles with diameters ranging from 3 to 8 mm were aspirated using a syringe and an 18G needle. Cumulus-oocyte complexes (COCs) were selected, and classified based on quality grade under a stereomicroscope, with only COCs grades I and II used for the study. The COCs were divided into four groups. The base maturation medium was supplemented with CBD, diluted in 0.05% DMSO, at concentrations of 0.1, 1, and 10 µM, depending on the experimental group. The control group was conducted without the addition of CBD but with 0.05% DMSO. The base maturation medium consisted of TCM199 with bicarbonate and Earle's salts, supplemented with recombinant follicle-stimulating hormone (0.1 IU/mL), sodium pyruvate (22 µg/mL), amikacin (75 µg/mL), and bovine serum albumin without fatty acids (BSA; 4 mg/mL). Four replicates were performed, each with 35 COCs. The COCs were matured at 38.5 °C in a humid atmosphere for 22-24 hours. Subsequently, matured COCs were photographed to assess the expansion of cumulus cells: poorly expanded (score 0), partially expanded (score 1), and fully expanded (score 2). The meiotic progress was examined under a microscope to determine the meiotic stage of the oocytes (Hoeschst 33342).

Results

Overall, CBD did not significantly affect meiosis progression in bovine oocytes (P = 0.20). However, CBD did lead to a decrease in the number of oocytes with a score of 1 (P= 0.05) and 2 (P= 0.02) and resulted in a significant increase in COCs with poor expansion (score 0, P= 0.04).

Conclusion

In vitro exposure to CBD resulted in the blockade of cumulus cell expansion in bovine oocytes matured in vitro. While some findings show promise, the use of CBD in fertility treatments must be approached cautiously, as ongoing studies are needed to assess safety and long-term reproductive effects. A deeper understanding of the relationship between CBD and oocyte maturation could provide valuable insights to address fertility challenges as research progresses.This study was financially supported by PIBIC/UNESP, CAPES, and FAPESP.

Keywords

cannabis, ovary, in vitro embryo production, fertility.