Banca de DEFESA: RAYANE BRANDAO RIBEIRO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : RAYANE BRANDAO RIBEIRO
DATE: 24/07/2023
TIME: 14:00
LOCAL: Meio virtual
TITLE:

Comparison of cryopreservation methods in domestic cat ovarian tissue: vitrification versus slow freezing

KEY WORDS:

slow freezing; vitrification; cryoprotectants; animal germplasm.

PAGES: 43
BIG AREA: Ciências Biológicas
AREA: Biologia Geral
SUMMARY:

The present study tested two cryopreservation techniques (vitrification and slow freezing) with different combinations of cryoprotectants. To perform the study, ovaries from 10 female cats submitted to elective ovariohysterectomy at Casa do Gato veterinary clinic, located in Brasília, DF, Brazil, were used. In total, 20 ovaries were collected, each of which was divided into eight 3mm³ fragments. Two fragments of each ovary were immediately fixed for fresh control, while the other six were divided into three to be vitrified and three to be cryopreserved by slow freezing. For the vitrification process, different equilibration (SE) and vitrification (SV) solutions were tested. These solutions included 10% dimethyl sulfoxide (DMSO) associated with 10% ethylene glycol (EG) and combined with 0.1M trehalose in the SE, and 20% DMSO and 20% EG with 0.1M trehalose in the SV (V1). Another solution consisted of 10% DMSO coupled with 10% EG and combined with 0.1M sucrose in SE, and 20% DMSO and 20% EG with 0.1M sucrose in SV (V2). A third solution was composed of 20% DMSO combined with 0.1M trehalose in SE and 40% DMSO combined with 0.1M trehalose in SV (V3). For slow freezing, the solutions consisted of 1M DMSO, 1M EG and 10% fetal bovine serum (FBS) combined with 0.4% trehalose (CL1), 1.5 M DMSO and 10% SFB combined with 0.4% sucrose (CL2) or 0.4% trehalose (CL3). All samples were stored in liquid nitrogen for at least seven days and the fragments were thawed or devitrified and fixed after this period. Histological analyses were performed to count and classify preantral follicles and immunohistochemical tests were performed to assess whether the follicles were proliferative. Group V1, had the highest rate of preservation of primordial follicle reserve and growing follicles and was shown to be the most effective in follicle survival. Thus, it can be inferred that vitrification using 10% DMSO, 10% EG and 0.1M trehalose showed beneficial effects, but future studies are needed for further proof of the effectiveness of the protocols presented.

COMMITTEE MEMBERS:
Externa à Instituição - ANA LUIZA SILVA GUIMARAES - CEULP
Interna - 1677467 - DANIELA MARA DE OLIVEIRA
Presidente - 3263789 - FERNANDA PAULINI
Externa à Instituição - MICHELLE SILVA ARAUJO - USP