Expression of ubiquitin C-terminal hydrolase-L1 and heatstroke-induced brain injury in mice / 医学研究生学报

ABSTRACT

Results With the prolonged exposure to heat , the mice exhibited swollen and disorderly arranged neurons , shrunken cells , and contracted and deeply stained nuclei , with significantly higher scores on nerve pathological injury evaluation at 6, 12, and 24 h (2.78 ± 0.71, 3.21 ±0.56, and 3.36 ±0.63) than the control mice (0.43 ±0.10) (P<0.05).ELISA showed remarkably elevated levels of UCH-L1 in the serum (F=147.7, P=0.05) and brain tissue (F=145.7, P=0.05) in the heat stress group as compared with the con-trol, and Western blot also revealed a markedly higher expression of UCH-L1 in the brain tissue in the former group than in the latterObjective The abnormal expression of ubiquitin C-terminal hydrolase-L1 ( UCH-L1 ) has an important role in the diagnosis and prognosis of brain damage .This study was to investigate the changes of UCH-L1 in the serum and brain tissue in the mouse model of heat stress . Methods Twelve BALB/c mice were randomly divided into a control and a heat stress group of equal number, the former placed at a temperature of (25.0 ±0.5)℃and a relative humidity of (35 ±5)%and the latter in a simulated in-cubator at (35.5 ±0.5)℃and a relative humidity of (60 ±5)%.When the rectal temperature reached 42℃, the animals were re-moved from the incubator and cooled at an ambient temperature of (25.0 ±0.5)℃and a humidity of (35 ±5)%for 0, 6, 12, and 24 h.Then the brain tissues of all the animals were harvested for HE staining , evaluation of neuronal injury under the light microscope , measurement of the UCH-L1 levels in the serum and brain tissue by ELISA , Western blot, and immunohistochemistry , respectively. (F=261.2, P=0.01).Immunohistochemistry manifested that , with the prolonged exposure to heat , the UCH-L1 expression in the brain tissue was characterized by gradually increased light brown of the neurons at staining . Conclusion Severe heatstroke causes brain injury in a time-dependent manner , and the abnormally elevated levels of UCH-L1 in the serum and brain tissue can be a marker of heatstroke-induced brain injury .