Structural and functional changes in islet beta cells in severely scalded rats / 中华烧伤杂志

<p><b>OBJECTIVE</b>To observe the structural and functional changes in islet beta cells in severely scalded rats, and to explore its relationship with dysfunction of glycometabolism.</p><p><b>METHODS</b>Seventy-two Wistar rats were divided into scald (S) group and sham injury (SI) group according to the random number table, with 36 rats in each group. Rats in group S were inflicted with 50%TBSA full-thickness scald by a 12-s immersion of back and a 6-s immersion of abdomen in 94 °C hot water. Rats in group SI were sham injured through immersion of back and abdomen in 37 °C warm water. At post injury hour (PIH) 6 and on post injury day (PID) 3 and 7, plasma glucose level was measured for intraperitoneal glucose tolerance test (IPGTT) in 12 rats of each group, and the area under the curve (AUC) of plasma glucose level was calculated. After the IPGTT, pancreatic tissue was harvested and subjected to a double immunostaining for insulin and cell nuclei to determine the pancreatic insulin-positive area ratio, and the area and number of beta cells in the islets (referred to as "the three indicators in the islets"). Data were processed with the analysis of repeated measures and factorial designed analysis of variance, and LSD test was applied for paired comparison.</p><p><b>RESULTS</b>(1) At PIH 6 and on PID 3, the overall plasma glucose levels of rats in group S before and after injection of glucose and at each time point were obviously higher than those of rats in group SI (with F values of main effects respectively 79.372 and 32.962, P values all below 0.001; with P values of paired comparison below 0.05 or 0.01). On PID 7, the overall plasma glucose levels in the two groups before and after injection of glucose and at each time point were close (with P values all above 0.05). (2) The overall AUC of plasma glucose levels of rats in group S was higher than that of rats in group SI (main effects: F = 337.87, P < 0.01). Compared with those of rats in group SI [(1019 ± 32), (1003 ± 72) mmol·min·L(-1)], the AUCs of plasma glucose levels of rats in group S were higher at PIH 6 and on PID 3 [(1501 ± 163), (1132 ± 67) mmol·min·L(-1), P values all below 0.001]. The AUCs of plasma glucose levels were close between two groups on PID 7 (P > 0.05). The AUCs of plasma glucose levels on PID 3 and 7 were both lower than that at PIH 6 in rats of group S (with P values all below 0.001). (3) The three indicators in the islets in rats of group S were all lower than those of rats in group SI (with F values of main effects respectively 135.17, 24.75 and 39.35, P values all below 0.01). There were no significant differences in the three indicators in the islets at PIH 6 between two groups (with P values all above 0.05). The three indicators in the islets of rats in group S on PID 3 and 7 [0.47 ± 0.05, 0.51 ± 0.07; (0.032 ± 0.008), (0.037 ± 0.008) mm(2); (303 ± 64), (341 ± 58) cells] were significantly lower than those of rats in group SI [0.63 ± 0.05, 0.64 ± 0.06; (0.043 ± 0.011), (0.044 ± 0.012) mm(2); (398 ± 112), (387 ± 90) cells; P < 0.05 or P < 0.01] and that at PIH 6 within group S (P < 0.05 or P < 0.01).</p><p><b>CONCLUSIONS</b>The number of beta cells is reduced, and the insulin secretion function of beta cells is decreased in the scalded rats, and they may constitute the cause of dysfunction of glycometabolism, mainly manifested as hyperglycemia.</p>

Mutant D178N prion protein converts spontaneously in RT-QuIC assay / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To study the conversion of mutant D178N prion protein in RT-QuIC assay.</p><p><b>METHODS</b>The D178N mutant prion PRNP was generated by the method of single site mutation. The mutant PRNP gene was inserted into plasmids of pET24. The full and N-truncated recombinant human prion proteins were expressed and purified. The fibril formations of these proteins were real-time monitored by the method of RT-QuIC. The ability to resist proteinase K (PK) of these fibrils was analyzed.</p><p><b>RESULTS</b>We succeed to construct human PrP-D178N plamids. The N-truncated human prion protein with D178N (PrP90-231-D178N) can convert spontaneously in RT-QuIC, while full length of human prion D178N protein (PrP23-231-D178N) fails to convert spontaneously. The spontaneously generated fibril has been domenstrated it is partily PK-resistant.</p><p><b>CONCLUSION</b>The N-terminal of prion protein (23-90) plays an important role for the D178N mutant protein spontaneously conversion, which provide the clues for study the pathogenesis of genetic CJD.</p>

Study on the correlation between membrane protein Flotillin-1 and PrPc endocytosis / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To explore whether the membrane-associated protein Flotillin-1 has relationship with endocytosis of PrPc.</p><p><b>METHODS</b>The expression of Flotillin-1 in different cell lines was detected with the method of Western Blot; the interaction between Flotillin-1 and PrPc in Cells which were treated with copper ions was observed using immunoprecipitation method.</p><p><b>RESULTS</b>(1) Flotillin-1 was widely expressed in many cell lines without significant difference in the amounts of expression level; (2) Only in the appearance of copper ions, the protein complexes of PrPc and Flotillin-1 can be detected with the method of IP, which were related to copper ions concentration and processing time.</p><p><b>CONCLUSION</b>The membrane-associated protein Flotillin-1 has the relationship with the endocytosis of PrPc.</p>