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Objective:To investigate the effects of vagus nerve stimulation on postoperative cognitive dysfunction and the role of hippocampal insulin growth factor 1 signaling pathway in aged mice.Methods:Seventy-five clean-grade C57 mice of both sexes, aged 21-23 months, weighing 28-34 g, were divided into 5 groups ( n=15 each) using a random number table method: sham operation group (group S), operation group (group O), operation + vagus nerve stimulation group (group O+ V), operation + IGF-1 siRNA group (group O+ I) and operation + vagus nerve stimulation + IGF-1 siRNA group (group O+ V+ I). Group O underwent exploratory laparotomy.Group O+ V received a 30-min electrical stimulation of the vagus nerve (intensity 0.5 mA, frequency 20 Hz, time 30 s, 6 times, interval 5 min) after the end of exploratory laparotomy.Group O+ I underwent exploratory laparotomy and inhaled IGF-1 siRNA solution 10 μl intranasally at 24 h before surgery and 24 and 48 h after surgery.Group O+ V+ I underwent electrical vagus nerve stimulation after exploratory laparotomy and inhaled IGF-1 siRNA solution 10 μl intranasally at 24 h before surgery and 24 and 48 h after surgery.Morris water maze tests were performed on 14-18 days after operation.On day 7 after operation, the mice were sacrificed and the hippocampus was obtained for determination of the expression of Bax, ionized calcium-binding adapter molecule 1 (Iba-1), insulin-like growth factor 1 (IGF-1), insulin-like growth factor 1 receptor (IGF1R), phosphorylated IGF1R (p-IGF1R), interleukin-1beta (IL-1β) and activated caspase-3 by Western blot. Results:Compared with group S, the escape latency was significantly prolonged on days 16-18 after operation, the frequency of crossing the platform was reduced, the time spent in the target quadrant was shortened, the expression of IGF-1 and p-IGF1R was down-regulated, and the expression of Iba-1, IL-1β, activated caspase-3 and Bax was up-regulated in group O ( P<0.05). Compared with group O, the escape latency was significantly shortened on days 16-18 after operation, the frequency of crossing the platform was increased, the time spent in the target quadrant was prolonged, the expression of IGF-1 and p-IGF1R was up-regulated, and the expression of Iba-1, IL-1β, activated caspase-3 and Bax was down-regulated in group O+ V ( P<0.05), and no significant change was found in the parameters mentioned above in group O+ I ( P>0.05). Compared with group O+ V, the escape latency was significantly prolonged on days 16-18 after operation, the frequency of crossing the platform was reduced, the time spent in the target quadrant was shortened, the expression of IGF-1 and p-IGF1R was down-regulated, and the expression of Iba-1, IL-1β, activated caspase-3 and Bax was up-regulated in group O+ V+ I ( P<0.05). There was no significant difference in the expression of IGF1R among the four groups ( P>0.05). Conclusions:Vagus nerve stimulation can reduce postoperative cognitive dysfunction, and the mechanism is related to activation of IGF-1 signaling pathway and reduction of hippocampal neuroinflammation and neuronal apoptosis in aged mice.
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Objective To evaluate the damage of the salivary gland in Sjogren's syndrome (SS)patients with normal Young's modulus value (YMV) using salivary gland dynamic imaging (SGDI).Methods A total of 78 parotid glands and submandibular glands of SS patients and 100 parotid glands and submandibular glands of healthy people were collected in this retrospective study.The difference of YMV between 2 groups was analyzed with two-sample t test;receiver operating characteristic (ROC) curves of YMV were drawn to calculate the area under carve (AUC) and cut-off values.SGDI was used to observe the uptake ratio of 15 min (UR15) value in the SS salivary glands with normal YMV.Results The YMV of left parotid/submandibular glands and right parotid/submandibular glands were not statistically different in both SS patients and healthy people (t values:from-1.192 to-0.404,all P＞0.05).The YMV of parotid/submandibular glands in SS patients was higher than that in healthy people:(15.39±8.08) vs (9.33±2.21) kPa,(14.35±5.33) vs (9.18±2.36) kPa (t values:7.169 and 8.662,both P＜0.05).ROC curves showed that the AUC of parotid glands and submandibular glands were 0.78 and 0.83.As the cut-off values of YMV were 10.85 kPa and 10.95 kPa,the sensitivity were 69.23％ (54/78) and 73.08％ (57/78),the specificity were 77.00％ (77/100) and 83.00％ (83/100),the positive predictive value were 70.13％ (54/77) and 77.03％ (57/74),the negative predictive value were 76.24％ (77/101) and 79.81％ (83/104),respectively.There was no statistically difference between YMV and UR15 for evaluating the SS parotid glands and submandibular glands (x2 values:0.963 and 0.896,both P＞0.05).The UR15 value of 78 SS parotid glands and submandibular glands were 1.42±0.97 and 1.19±0.83,respectively.About 58.33％ (14/24) parotid glands with normal YMV (＜10.85 kPa) and 76.19％ (16/21) submandibular glands with normal YMV (＜10.95 kPa)had reduced cellular uptake in SS patients.Conclusions Parotid glands and submandibular glands in SS patients are damaged,and the tissue hardness is increased.SGDI can discover the cellular damage in SS salivary glands with normal YMV.
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To understand the Escherichia coli (E .coli) O157∶ H7 isolated from cow in Zhengzhou ,Henan Province ,a total of 146 samples of cow fecal and milk were collected in the different farms ,and E .coli O157∶ H7 was detected with mul-tiplex polymerase chain reaction (PCR) in our laboratory .Then the biochemical characteristics ,growth dynamic ,the biofilm formation ,and the toxin genes of the E .coli O157∶ H7 isolates were analyzed .The results showed that 2 strains of E .coli O157∶H7 were found ,with the detection rate of 1 .4% ,and the isolates were named as L1 and L2 in current study ,respec-tively .The E .coli O157∶H7 clinical isolates had the same biochemical characteristics with that of the typical E .coli .The L1 and L2 isolates presented similar growth curve ,which entered into the log phase earlier than that of the standard strain .L1 strain formed thick ,confluent ,complete biofilm after 48 hours post-inoculation ,and the biofilm of L2 strain was formed com-pletely in 36 hours .The two E .coli O157∶ H7 isolates were positive with eaeA and hlyA genes ,and the L1 strain also carried the Stx2 virulence gene .Our results reinforce the epidemiological data of E .coli O157∶H7 ,and underscore the need for more effective surveillance of animal-derived E .coli O157∶H7 isolates in Zhengzhou City ,China .