Macrophage migration inhibitory factor antagonist (p425) ameliorates kidney histopathological and functional changes in diabetic rats / Antagonista (p425) do fator de inibição da migração de macrófagos (MIF) melhora as alterações histopatológicas e funcionais renais em ratos diabéticos

Abstract Introduction: It is hypothesized that increased macrophage migration inhibitory factor (MIF) expression may contribute to diabetic nephropathy (DN) pathogenesis. The aim of the present study was to investigate the renal effects of MIF inhibition in a diabetic experimental model. Methods: Eighteen male Wistar rats (230 ± 20 g) were divided into three groups: 1) control, 2) diabetic (STZ, 50 mg/kg, dissolved in saline, ip), 3) diabetic + MIF antagonist (p425, 1 mg/kg per day, ip, on the 21th day, for 21 consecutive days). The treatment started since we founwd a significant increase in urine albumin excretion (UAE) rate in the diabetic rats in comparison with the control rats. The rats were kept individually in metabolic cages (8 AM-2 PM) and urine samples were collected in the 21 and 42th day. At the end, blood and tissue samples were collected for biochemical (BS, UPE, urine GAG, BUN, Cr, Na, and K) and histological analyses. Results: The results of this study showed that MIF antagonist (p425) significantly decreased urine protein and GAG excretion, urine protein/creatinine ratio, and serum BUN and Cr in the streptozotocin-induced DN in the rats. Pathological changes were significantly alleviated in the MIF antagonist (p425)-administered DN rats. Conclusion: Collectively, these data suggested that MIF antagonist (p425) was able to protect against functional and histopathological injury in the DN.

Resumo Introdução: Supõe-se que elevações da expressão do fator de inibição da migração de macrófagos (MIF) possam contribuir para a patogênese da nefropatia diabética (ND). O objetivo do presente estudo foi investigar os efeitos renais da inibição do MIF em um modelo experimental diabético. Métodos: Dezoito ratos Wistar machos (230 ± 20g) foram divididos em três grupos: 1) controle, 2) diabético (STZ 50 mg/kg dissolvida em soro fisiológico, IP), 3) diabético + antagonista do MIF (p425 1 mg/kg por dia IP no 21o dia por 21 dias consecutivos). O tratamento começou após a identificação de aumento significativo na albuminúria nos ratos diabéticos em relação aos controles. Os ratos foram mantidos individualmente em gaiolas metabólicas (8h-14h) e amostras de urina foram colhidas no 21o e no 42o dia. Ao final do estudo, amostras de sangue e tecido foram colhidas para análises bioquímicas (BS, excreção urinária de proteína, excreção urinária de GAGs, BUN, Cr, Na e K) e histológicas. Resultados: O presente estudo demonstrou que o antagonista do MIF (p425) diminuiu significativamente proteinúria, excreção urinária de GAGs , relação proteína/creatinina na urina, BUN e Cr no grupo com ND induzida por estreptozotocina. As alterações patológicas foram significativamente abrandadas nos ratos com ND que receberam antagonista do MIF (p425). Conclusão: Coletivamente, os dados sugerem que o antagonista do MIF (p425) teve efeito protetor contra lesões funcionais e histopatológicas da ND.

Effect of xanthohumol on melanogenesis in B16 melanoma cells

Xanthohumol (XH), the principal prenylflavonoid of the hop plant (Humulus lupulus L.), dose-dependently inhibited isobutylmethylxanthine (IBMX)-induced melanogenesis in B16 melanoma cells, with little cytotoxicity at the effective concentrations. Decreased melanin content was accompanied by reduced tyrosinase enzyme activity, protein and mRNA expression. The levels of tyrosinase-related protein 1 and 2 mRNAs were decreased by XH. XH also inhibited alpha-melanocyte stimulating hormone- or forskolin-induced increases in melanogenesis, suggesting an action on the cAMP-dependent melanogenic pathway. XH downregulated the protein and mRNA expression of microphthalmia-associated transcription factor (MITF), a master transcriptional regulator of key melanogenic enzymes. These results suggest that XH might act as a hypo-pigmenting agent through the downregulation of MITF in the cAMP-dependent melanogenic pathway.