title: Morphology and Molecular Mechanisms of Hepatic Injury in Rats under Simulated Weightlessness and the Protective Effects of Resistance Training.
abstract: This study investigated the effects of long-term simulated weightlessness on liver morphology, enzymes, glycogen, and apoptosis related proteins by using two-month rat-tail suspension model (TS), and liver injury improvement by rat-tail suspension with resistance training model (TS&RT). Microscopically the livers of TS rats showed massive granular degeneration, chronic inflammation, and portal fibrosis. Mitochondrial and endoplasmic reticulum swelling and loss of membrane integrity were observed by transmission electron microscopy (TEM). The similar, but milder, morphological changes were observed in the livers of TS&RT rats. Serum biochemistry analysis revealed that the levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were significantly higher (p<0.05) in TS rats than in controls. The levels of ALT and AST in TS&RT rats were slightly lower than in RT rats, but they were insignificantly higher than in controls. However, both TS and TS&RT rats had significantly lower levels (p<0.05) of serum glucose and hepatic glycogen than in controls. Immunohistochemistry demonstrated that the expressions of Bax, Bcl-2, and active caspase-3 were higher in TS rats than in TS&RT and control rats. Real-time polymerase chain reaction (real-time PCR) showed that TS rats had higher mRNA levels (P < 0.05) of glucose-regulated protein 78 (GRP78) and caspase-12 transcription than in control rats; whereas mRNA expressions of C/EBP homologous protein (CHOP) and c-Jun N-terminal kinase (JNK) were slightly higher in TS rats. TS&RT rats showed no significant differences of above 4 mRNAs compared with the control group. Our results demonstrated that long-term weightlessness caused hepatic injury, and may trigger hepatic apoptosis. Resistance training slightly improved hepatic damage.
authors.affiliation: Department of Veterinary Pathology, Laboratory of Veterinary Pathology and Public Health,College of Veterinary Medicine, China Agricultural University, Beijing, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Du
authors.affiliation: Department of Veterinary Pathology, Laboratory of Veterinary Pathology and Public Health,College of Veterinary Medicine, China Agricultural University, Beijing, China.
authors.forename: Ye
authors.initials: Y
authors.lastname: Ding
authors.affiliation: National Animal Protozoa Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Zou
authors.affiliation: State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Centre, Beijing, China.
authors.forename: Zhili
authors.initials: Z
authors.lastname: Li
authors.affiliation: Department of Veterinary Pathology, Laboratory of Veterinary Pathology and Public Health,College of Veterinary Medicine, China Agricultural University, Beijing, China.
authors.forename: Jijing
authors.initials: J
authors.lastname: Tian
authors.affiliation: Department of Veterinary Pathology, Laboratory of Veterinary Pathology and Public Health,College of Veterinary Medicine, China Agricultural University, Beijing, China.
authors.forename: Ruiping
authors.initials: R
authors.lastname: She
authors.affiliation: State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Centre, Beijing, China.
authors.forename: Desheng
authors.initials: D
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Centre, Beijing, China.
authors.forename: Huijuan
authors.initials: H
authors.lastname: Wang
authors.affiliation: Department of Veterinary Pathology, Laboratory of Veterinary Pathology and Public Health,College of Veterinary Medicine, China Agricultural University, Beijing, China.
authors.forename: Dongqiang
authors.initials: D
authors.lastname: Lv
authors.affiliation: Department of Veterinary Pathology, Laboratory of Veterinary Pathology and Public Health,College of Veterinary Medicine, China Agricultural University, Beijing, China.
authors.forename: Lingling
authors.initials: L
authors.lastname: Chang
mesh_terms: D000410:Alanine Transaminase / Q000378:metabolism; D000818:Animals; D017209:Apoptosis / Q000502:physiology; D001219:Aspartate Aminotransferases / Q000378:metabolism; D053454:Caspase 12 / Q000378:metabolism; D053148:Caspase 3 / Q000378:metabolism; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism; D019417:Hindlimb Suspension; D008099:Liver / Q000378:metabolism* / Q000473:pathology; D008107:Liver Diseases / Q000378:metabolism* / Q000473:pathology; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism; D010805:Physical Conditioning, Animal / Q000502:physiology*; D051381:Rats; D055070:Resistance Training; D018474:Weightlessness Simulation
chemical_list: D018840:HSP70 Heat-Shock Proteins; D008565:Membrane Proteins; C018551:glucose-regulated proteins; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase; D053454:Caspase 12; D053148:Caspase 3