The damage of liver cells and the expression of GRP 78 in rats liver tissue after repeated and sustained exposure to different +Gz / 基础医学与临床

ABSTRACT

Objective To observe the damage of liver cells and to investigate the distribution and expression of glu-cose-regulated protein 78 (Glucose regulated protein78, GRP78/Bip) in liver tissue under the positive acceleration (+Gz) exposure.Methods Totally 24 wistar rats were randomly assigned to four groupsblank control,+6Gz,+9Gz and +12Gz.Each rat was clamped to the centrifuge arm , prone position, with the head of the rat facing the axis of the centrifuge for +Gz orientation.The onset rate was +0.5 Gz/s, which was used trapezoidal acceleration curve effect and controlled by computer .Blank control group rats were placed on the arm of centrifuge and under-went a process similar to that described above , but they were not exposed to acceleration .+6Gz group,+9Gz group and +12Gz group were subjected at peak time 3 min in animal centrifuge , acceleration rate 0.5 G/s, five times with interval 30 min between times.In addition, liver tissue of rats were respectively observed by H .E.staining.Mean while, plasma aspartate aminotransferase ( AST) and alanine aminotransferase ( ALT) were tested determine the damageofliverfunction.Results +GzaccelerationstressinjuryincreasedserumASTandALTlevel.Compared with the stress control, +9Gz group and +12Gz group significantly increased in plasma ALT and AST as compared with control group ( P<0.05 ) .+12 Gz stress induced the highest level in these groups .The level of ALT in+2 Gz group was higher than that in +6 Gz group ( P<0.05 ) .HE staining showed derangement of liver cells , irregular shape, the cell gap is not clear, vacuolar changes in +Gz groups, and with the increase of G value.Compared with the control group, the expression of GRP78/Bip was focused in the cytoplasm;the expression of GRP78 in the experimental group is higher than that in the control group ( P<0.05 ) .+12 Gz group was significantly higher than+6Gz group and the control group (P<0.05).The expression of GRP78/Bip in liver tissue increased with the in-creasing of G value levels;the expression level of GRP78/Bip in +12Gz and +9Gz groups were higher than that in +6Gz and control group (P<0.05).Conclusions There is positively related expression of GRP78/Bip, which was associated with exposure of increasing G values .