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ObjectiveTo investigate the effect of the protein kinase RNA-like endoplasmic reticulum kinase （PERK）/eukaryotic initiation factor 2α （eIF2α） pathway in endoplasmic reticulum stress on the activation of hepatic stellate cells （HSC）. MethodsPathological sections of normal liver tissue after surgery were collected from 11 patients with hepatic fibrosis （S1-S4） and 9 patients with hepatic hemangioma and hepatic adenoma confirmed by liver biopsy， and immunohistochemistry was used to measure the protein expression levels of PERK， eIF2α， and C/EBP homologous protein （CHOP）. Human HSC-LX2 cells were treated with different concentrations of the endoplasmic reticulum stress inducer thapsigargin （0， 125， 250， 500， and 1 000 nmol/L）， and qRT-PCR was used to measure the mRNA expression level of PERK， while Western blot was used to measure the protein expression levels of PERK， inositol requiring protein 1 （IRE1）， activating transcription factor 6 （ATF6）， CHOP， and α-smooth muscle actin （α-SMA）. The method of lentivirus transfection was used to construct a PERK stable overexpression LX-2 group and a control group； qRT-PCR was used to measure the mRNA expression levels of PERK， eIF2α， and α-SMA， Western blot was used to measure the protein expression levels of PERK， phosphorylated eIF2α （p-eIF2α）， and α-SMA， and immunofluorescence assay was used to measure the expression of collagen type I alpha 1 （COL1A1）. The independent samples t-test was used for comparison of normally distributed continuous data between two groups； a one-way analysis of variance was used for comparison between multiple groups， and the least significant difference t-test was used for further comparison between two groups. The Mann-Whitney U test was used for comparison of non-normally distributed continuous data between two groups. ResultsCompared with normal liver tissue， the liver tissue of patients with hepatic fibrosis had significantly higher expression levels of PERK， eIF2α， and CHOP （Z=-3.56， t=-5.75， Z=-3.52， all P<0.001）. Compared with the solvent group， the groups treated with different concentrations of thapsigargin had significant increases in the expression levels of the endoplasmic reticulum-associated proteins PERK， CHOP， IRE1， ATF6， and α-SMA （all P<0.05）. Compared with the control group， the PERK stable overexpression group had significant increases in the mRNA expression levels of PERK， eIF2α， and α-SMA and the protein expression levels of PERK， p-eIF2α， and α-SMA （all P<0.05）， and immunofluorescence assay showed a significant increase in the expression level of COL1A1 in the PERK stable overexpression group （P<0.05）. ConclusionPERK overexpression can induce the expression of α-SMA and COL1A1 in LX-2 cells， suggesting that the PERK signaling pathway might be one of the important mechanisms of HSC activation.
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Objective@#To explore the correlation between pull-up ability and upper body composition of male college students in a college in Guangxi, and to provide scientific guidance for college students’ exercise.@*Methods@#A total of 685 male college students were randomly selected from a college in Guangxi.Pull up tests were implemented according to the national physical health test standards. Measurements of muscle mass, fat mass, fat percentage, etc. of the upper limbs were conducted by using the Ogilvy Body Composition Meter (TANITA MC-180). Data entry and analysis were performed by using SPSS 23.0.@*Results@#The pass rate of male college students in the region was 21.7%; There was a statistically significant difference in the fat mass and percentage of body fat between males with different pull-up ability (F=11.30，14.18，12.91，15.22，P<0.01).After controlling age, height, weight and BMI, partial correlation analysis showed that there was a negative correlation between the pull-up ability of male college students and the fat mass and limb fat rate of both upper limbs(r=-0.22, -0.33, -0.31, -0.38, P<0.01).@*Conclusion@#The ability of male students in Guangxi to pull up is needed to be improved. Pull-up exercises can reduce fat mass and fat percentage in the upper limbs and improve body composition.