Atividade citoprotetora da berberina, um alcalóide isoquinolínico, sobre a toxicidade celular induzida pela 6-hidroxidopamina (6-OHDA) em células SH-SY5Y

Abstract

Parkinson’s disease is the second more common neurodegenerative sickness and it affects about 1% of the world population. Environment and genetics factors may interact and contribute to the disease’s development. The 6-hydroxydopamine (6-OHDA) is a neurotoxin that acts on catecholaminergic neurons throughthe formation of reactive oxygen species and inhibition of the electron transport chain’s complex I. The berberine is a natural isoquinolinium alkaloid with antioxidant activity and action in the mitochondrial membrane. The present study aimed to investigate the cytoprotective activity of berberine in cell degeneration model induced by 6-OHDA in cultured SH-SY5Y cell. Berberine (10, 25 and 50 µg/mL) was added to the cells 15 minutes before 6-OHDA 50µM and, after 24 hours, the tests were made for evaluation of cellular viability (MTT and propidium iodide-IP), oxidative stress (nitrite, TBARS), morphology/apoptosis (hematoxilin/eosin, ethidium bromide/acridine orange) and mitochondrial transmembrane potencial (rhodamine 123). 6-OHDA reduced significantly the cellular viability (Control: MTT=99,62%, IP=98,63%; 6-OHDA: MTT=49,79%, IP= 48,80%), increased the nitrite (71,8%) and the malondialdehyde levels (27%). It was observed fragmentation and reduction of cell volume, loss of neuritis, large percentage of apoptotic and necrotic cells (Control: viable=23,75%, apoptotic=61,92%, necrotic=1,83%; 6-OHDA: viable= 23,75%, apoptotic= 61,92%, necrotic= 14,34%) and of cells with mitochondrial depolarization 56%. Berberine significantly protected (p<0,05) cells from damage induced by 6-OHDA, increasing cell viability (MTT: BERB 25 + 6-OHDA= 68,10 ± 4,49; BERB 50 + 6-OHDA= 78,81± 2,31%. IP: BERB 25 + 6-OHDA= 60,38 ± 0,92; BERB 50 + 6-OHDA= 57,45 ± 1,33%), reduced nitrite (BERB 25 + 6-OHDA= 6,16 ± 0,42; BERB 50 + 6-OHDA= 6,20 ± 0,40µM) and malondialdehyde levels (BERB 25+ 6-OHDA= 8,53; BERB 50 + 6-OHDA= 6,8 µM). Furthermore, berberine reduced morphology cell alterations, apoptotic death (BERB 25 + 6-OHDA= apoptosis-26,51%; BERB 50 + 6-OHDA= apoptosis-30,32%) and number of cells with mitochondrial depolarization (BERB 25+ 6-OHDA= 7,58; BERB 50 + 6-OHDA= 12,9%). These results show that the cytoprotection of berberine, possibly by its antiapoptotic effects, may be related to a mitochondrial protection and/or an antioxidant action. Thus, we suggest that berberine may be prospected as a possible neuroprotective agent for Parkinson’s disease.