ABSTRACT
Aim To observe the expression of mesen-cephalic astrocyte-derived neurotrophic factor(MANF) in synovial membrane and serum of rats with adjuvant arthritis (AA) and to analyse the relationship between MANF expression and arthritis. Methods AA models were prepared by injecting Freund complete adjuvant (FCA) into SD rats. The swelling of the secondary joint was measured by foot volume measurement. The severity of AA was recorded by arthritis index (AI). Synovial pathological changes were observed by HE staining. The protein and mRNA levels of MANF,BiP and CHOP extracted from synovial tissues in different periods of AA rats were detected by Western blot and reverse transcription-polymerase chain reaction (RT-PCR), respectively. The levels of MANF, C-reactive protein (CRP), interleukin-1β (IL-1β) and tumor necrosis factor α (TNF-α) in serum were detected by enzyme-linked immunosorbent assay (ELISA) and then the relationship between MANF level and inflam-matory factors were explored. Results AA rat model was established successfully. The expression of BiP significantly increased in synovial tissue on d 2 after CFA injection,and decreased until d 28. The expres-sion of MANF slightly increased on d 2,then remained stable,and significantly increased on d 14, and then decreased gradually. The expression of CHOP kept to rise slowly at a low level. The level of MANF in serum markedly increased on d 14,then gradually decreased, but it was still higher than the normal level on d 28. The level of CRP exhibited similar trend with MANF. Correlation analysis showed that MANF had a negative correlation with arthritis symptoms, IL-1β and TNF-α in the secondary inflammatory period of AA rats. Con-clusions Arthritis induces the expression and secre-tion of MANF,and the level of MANF is closely relat-ed to the progression and severity of arthritis.
ABSTRACT
Aim To investigate the protective effects of MANF on human neuroblastoma SH-SY5 Y cells suf-fering from oxygen-glucose deprivation/reperfusion ( OGD/R) and the underlying mechanism. Methods SH-SY5Y cells were treated with OGD for 6 h, fol-lowed by reperfusion for 12 h. Meanwhile, the cells were incubated with 2 μmol · L-1 recombinant human protein MANF for 12 h during reperfusion. The cell morphology was observed under an optical microscope. The cell viability was determined by MTT assay. PI staining was performed to detect the number of dead cells. Western blot was performed to determine the protein levels of endogenous MANF, glucose-related protein 78 ( GRP78/BiP) , phosphorylated inositol re-quiring enzyme 1 ( p-IRE1 ) , phosphorylated eukaryot-ic translation initiator factor 2α ( p-eIF2α) , cleaved caspase-3, and C/EBP-homologous protein (CHOP). Results The cells exposed to OGD/R became smaller and round, and the neurites of the cells were shortened or disappeared . Recombinant human protein MANF improved the survival rate ( P and cleaved caspase-3 in SH-SY5 Y cells induced by OGD/R were significantly suppressed by MANF. Con-clusion OGD/R up-regulates the ER stress-associated proteins and causes apoptosis. MANF inhibits OGD/R-induced cell death, which may be related to attenua-ting ER stress-induced apoptosis.