Banca de DEFESA: KAROLINE RACHEL TEODOSIO DE MELO

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE : KAROLINE RACHEL TEODOSIO DE MELO
DATA : 29/06/2018
HORA: 14:00
LOCAL: Anfiteatro dos Répteis
TÍTULO:

OBTENTION OF SULFATED POLYSACCHARIDES FROM BROWN ALGAE Dictyopteris justii AND ITS ACTION AGAINST INJURIES IN KIDNEY CELLS CAUSED BY OXIDATIVE STRESS DUE BY HYDROGEN PEROXIDE AND OXALATE

PALAVRAS-CHAVES:

fucana; glucan; urolithiasis, bioactive polysaccharides.

PÁGINAS: 97
GRANDE ÁREA: Ciências Biológicas
ÁREA: Bioquímica
RESUMO:

Oxalate crystals are the main components of urinary stone and these are closely related to oxidative stress in urolithiasis. It is estimated that around 10% of the world population is affected by this condition. Because of this, recent studies have looked for components that are capable of inhibiting this phenomenon. Studies with sulphated polysaccharides from brown algae Dictyopteris justii have shown that they are potent antioxidants, and they are inhibitors of the formation of these crystals in vitro. Based on the data obtained previously, the objective of this study was to obtain four fractions rich in sulphated polysaccharides (DJ-0.3v, DJ-0.4v, DJ-0.5v, and DJ-1.2v) and verify their chemical and its action as protective and repair agents against the oxidative stress caused by hydrogen peroxide and oxalate crystals. As results, it was observed that D. justii synthesizes populations of different sulfated polysaccharides. The first one, found in DJ-0.3v is rich in glucose, xylose and glucuronic acid and shows traces of fucose; the second (DJ-0.4v), has as a differential large amounts of fucose; the two populations found in DJ-0.5v and DJ-1.2v show only glucose and fucose traces, but differ in the amount of sulfate grouping. All the sulphated polysaccharides presented total antioxidant capacity and modified the morphology of calcium oxalate crystals formed in vitro, proving the identity of these biomolecules. The cytotoxicity study in HEK-293 and MDCK showed that DJ-0.3ve DJ-0.4v fractions were only cytotoxic in concentrations above 2 mg / mL and DJ-0.5ve DJ-1.2v fractions were not cytotoxic in any of the concentrations studied. The protective and repairing effect of these polysaccharides was also observed. Prophylactic treatment of all sulphated polysaccharides in HEK-293 cells up to the maximum concentration of 1 mg / mL seems to maintain cell viability against damage caused by hydrogen peroxide in human renal embryonic cells. On the other hand, with the exception of the DJ-0.3v fraction all fractions had a repairing effect on the cells, with emphasis on the DJ-0.5v fraction, whose treatment maintained the highest number of viable cells in both processes. In dog kidney cells (MDCK), the prophylactic effect was also verified and it was found that only treatments with DJ-0.4v and DJ-0.5v were able to protect cells against damage. In addition, they decrease the expression of osteocalcin, a marker of bone differentiation, which is related to the process of mineralization and hypercalciuria, mechanisms involved in calculus formation. Possibly, these polysaccharides act by increasing the expression of antioxidant enzymes or by acting in conjunction with them. The data obtained lead us to propose that these polysaccharides are promising agents for use in the treatment of urolithiasis.

MEMBROS DA BANCA:
Presidente - 046.477.204-46 - LEANDRO SILVA COSTA - IFRN
Externo à Instituição - ALEXANDRE COELHO SERQUIZ - UNI-RN
Externo à Instituição - ANA KATARINA MENEZES DA CRUZ SOARES - UnP
Externo à Instituição - ANDREZA ROCHELLE DO VALE MORAIS - FACENE
Externo à Instituição - DIEGO DE ARAUJO SABRY - IFRN