| OBJACTIVE:To observe renal endoplasmic reticulum stress protein expression of cold and lipopolysaccharide(LPS) stimulation in rats, and to explore the relationship between cold and LPS stimulation of endoplasmic reticulum and kidney injury.METHODS:126 SD rats were divided into simple cooling group and cooling +LPS group by random. Each one included normal temperature group, 4℃cooling group and -16℃cooling group. Every group was observed in seven time points:1h, 4h, 8h, 12h, 24h, 48h and 7d respectively, and each one has three rats. Experimental animals which had been fed in normal temperature for seven days were fed in the climate box which had been set into 4℃/-16℃. The LPS groups were peritoneally injected with LPS which was prepared with no heat source water of 1 milligram per 1 kilogram of rat weight. At 1h, 4h, 8h, 12h, 24h, 48h, 7d, Animals were sacrificed. The left kidneys was taken and embedded with paraffin. The kidney tissues of rats in all groups were stained by hematoxylin-eosin(HE), and the renal histopathological changes were observed. The expressions of GRP78 and Caspase12 were evaluated by immunohisto- chemical staining and their average optical density(AOD) and integrated optical density(IOD)were assessed quantitatively by HMIAS-2000 image analysis system.RESULTS:With temperature decreasing, histopathologic injury was aggravated and appeared earlier in the rat kidney tissue. Injury of most of tulular epithilial cells could be observed in the simple cooling groups, and injury of most of glomerular could be observed in the simple LPS group. In the cooling +LPS groups, there were mainly injuried the majority of glomerular and tubular epithelial cells. Compared with the simple cooling groups, the pathological injury was more serious in the cooling+LPS groups. All cooling groups had the most serious at 24h. With temperature decreasing, the expression of GRP78 and Caspase12 were more and more and occurred much sooner, which mainly appeared in the tubular epithelial cells of groups, but also had a small amout in glomerular. Compared the control group with the simple LPS group, the expression of GRP78 and Caspase12 was similar. There were more expression in the cooling+LPS groups, compared to the simple cooling group. All cooling group had the most expression at 24h.With temperature decreasing, AOD and IOD of GRP78 and Caspase12 in simple cooling groups were higher. There was a distinct difference among groups(P<0.05). The AOD and IOD of of GRP78 and Caspase12 at 24h was the highest in two cooling groups. Compared to the simple LPS group, the AOD and IOD of GRP78 and Caspase12 in cooling+LPS groups was higher. There was a distinct difference among groups(P<0.05). There was no distinct difference between simple LPS group and control group in the expression of GRP78 and Caspase12(P>0.05). Compared to the simple cooling groups, the expression of the cooling+ LPS groups was more(P<0.05). All cooling group had the most expression at 24h.CONCLUSION:After suffered cold stimulation, histopathological injury and increased expression of GRP78 and Caspase12 are observed in kidney. These changes become more serious with time, and are the most obvious at 24h. There are only mild traumatic changes in the simple LPS group which is injected LPS of 1 milligram per 1 kilogram of rat weight, but when rats are co-stimulated with cold and LPS, the histopathological changes and increased expression of GRP78 and Caspase12 are more obvious than those in simple cooling stimulation. The results show cold and LPS stimulation can induce the endoplasmic reticulum stress in kidney... |
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