We have previously reported free radical production after traumatic brain injury (TBI), which induces neural stem cell (NSC) degeneration and death. However, the effects of aging on NSC proliferation around the damaged area following TBI have not been investigated. Therefore, in this study, we used 10-week (young group) and 24-month-old (aged group) rat TBI models to investigate the effects of aging on NSC proliferation around damaged tissue using immunohistochemical and ex vivo techniques. Young and aged rats received TBI. At 1, 3 and 7 days after TBI, immunohistochemical and lipid peroxidation studies were performed. Immunohistochemistry revealed that the number of nestin-positive cells around the damaged area after TBI in the aged group decreased significantly when compared with those in the young group (P < 0.01). However, the number of 8-hydroxy-2'-deoxyguanosine-, 4-hydroxy-2-nonenal- and single-stranded DNA (ssDNA)-positive cells and the level of peroxidation around the damaged area after TBI significantly increased in the aged group, compared with those in the young group (P < 0.01). Furthermore, almost all ssDNA-positive cells in young and aged groups co-localized with NeuN and nestin staining. Ex vivo studies revealed that neurospheres, which differentiated into neurons and glia in culture, could only be isolated from injured brain tissue in young and aged groups at 3 days after TBI. These results indicate that, although there were fewer NSCs that have the potential to differentiate into neurons and glia, these NSCs escaped free radical-induced degeneration around the damaged area after TBI in the aged rat brain.
Age-related alterations and differences of weights and those of amino acid concentrations in the cerebrospinal fluid (CSF) were evaluated between Sprague Dawley (SD) rats and Wistar Kyoto (WKY) rats from eight to twenty weeks of age. The weights of SD rats were heavier than WKY rats at all ages. The age-related alterations of the CSF concentration of many amino acids within each strain were significant but showed no significant trend with age. Between the strains, the concentration differences of excitatory and inhibitory amino acids were not frequent although the concentrations of arginine, alanine and threonine were significantly higher in SD rats than in WKY rats. These results suggest that the different CSF concentrations of amino acids may relate to characteristics of rat strains. Key words: amino acid, cerebrospinal fluid, rat age-related alterations of amino acids in CNS are still unknown.We selected Sprague Dawley (SD) and Wistar Kyoto (WKY) rats as models because they exhibit different memory capabilities and stress sensitivities [7,9,10,13], and we evaluated the differences and the age-related alterations of amino acid concentrations in CSF.Ten males each of SD rats purchased from Japan SLC Inc., Shizuoka, Japan and WKY rats reproduce in our institute were used in this experiment. They were bred in the Life Science Research Institute, Kinki University School of Medicine, and were maintained under controlled conditions (temperature 23 ± 0.5°C; humid-
A simple technique of choledochojejunostomy in rats is introduced in this paper and its suitability for use is as an experimental model. The healing characteristics of sutureless choledochojejunostomy rat (C-J rat) were investigated in a rat experimental model. The common bile duct of 10 conditioned Wistar rats was exposed, divided transversely and a choledochojejunostomy constructed with only a vinyl chloride tube positioned between the common bile duct and jejunum. The animals were sacrificed on 12 weeks after surgery. From the serum biochemical examination on 12 weeks after surgery, serum bilirubin, AST and ALT in C-J rat were similar to those of control. But Alp in C-J rat is significantly increased compared to control due to stent tube. Therefore, there is no problem about the bile flow via choledochojejunostomy in C-J rat. The results of the present study indicate clearly that the sutureless anastomosis in a rat model is reliable and leads to long-term anastomotic patency at 12 weeks after surgery. Sutureless choledochojejunostomy may have an application in the reconstruction of narrow and fragile bile duct. Our technique will be suitable for the cases of narrow and fragile bile duct which standard biliary enteric anastomosis is impossible.
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