| Objective :To study the influence of sea water emersion on glucose metabolism in rats with laparotomy by evaluating time-course changes of serum glucose and IPGTT test related values.Contents and methods :18 male SD rats were divided in to 3 groups according to received operations, the control group (n=6), the laparotomy and exposure in air for 45min group (L45 group, n=6) and the laparotomy and sea water emersion for 45min group (L+S45 group, n=6). The values of pre- and post-operation body temperature, random blood glucose and IPGTT were measured at different time points. Body temperatures (rectum temperature) were measured with an electronic thermometer. Random blood glucose was measured with a micro blood glucose instrument and blood samples acquired by tail puncture. IPGTT were conducted by AMDCC protocol with minor modification, rat was fasted for 6 hours before IPGTT, 10% glucose solution was injected intraperitoneally with dosage of 0.01ml/g bodyweight. Blood glucose values are measured at 5, 15 30, 60, and 120 min .Results :No differences of body weight, temperature, random glucose and IPGTT values were found among 3 groups before operation. The post-operation measurements showed: (i) Core temperature declined in L45 group and L+S45 group after operation for different time duration. L+S45 group showed more severe and prolonged hypothermia than L45group. (ii) Post-operation hyperglycemia was found in L45 group and L+S45 group till 90 hours after operation. Glucose value at the end of operation was higher in L45 group than in L+S45 group. Hyperglycemia was gradually improved from 6 hours after operation in both groups. Random glucose values were higher in L+S45 group and L45 group from 18 to 90 hours post-operation.(iii) Abnormal IPGTT values were found in L45 group and L+S45 group after operation. The area under curve was increased respectivily. More severe and prolonged IPGTT abnormality was found in L+S45 group than in L45 group after operation. The control group showed no change after operation.Conclusions: (i) Hyperglycemia is not so significant at early post-operation stage in sea water emersion group than that in laparotomy group. (ii) Sea water emersion aggravates and prolongs IPGTT abnormality induced by injury of laparotomy (iii) Sea water emersion aggravates hypothermia induced by injury of laparotomy.Part 2. The study on relationship between Early Stage IPGTT Abnormality and Organ Injury Markers in Rat with Laparotomy and Sea Water EmersionObjective The study was held to evaluate the impacts of trauma, hypothermia and hyperosmotic stress on glucose metabolic abnormality and the significance of glucose metabolic abnormality in Laparotomy and Sea Water Emersion model by analyzing relationships between post-injury IPGTT indexes and Organ Injury Markers.Contents and methods 30 male SD rats were divided into 5 groups according to received operations, the control group (C group, n=6), the laparotomy only group (L group, n=6), the laparotomy and exposure in air for 45min group (L45 group, n=6), the laparotomy and Ringers solution emersion for 45min group (L+R45 group, n=6) and the laparotomy and sea water emersion for 45min group (L+S45 group, n=6). The values of body temperature in 12 hours, IPGTT at 12 hours and serum biochemistry markers at 14 hours after operation were measured. Body temperatures measurements and IPGTT were conducted as protocols in experiment part 1. The biochemistry markers, such as ALT, AST, Cr, BUN, CK and electrolytes (Na, K, Ca, Cl), were measured 14 hour after operation. The blood samples drew from inferior vena cava were centrifuged 3000rpm for 10 minutes to acquire serum for biochemistry tests. Results No differences of body weight, temperature, random glucose and IPGTT values were found among 5 groups before operation. The post-operation measurements showed: (i) All groups showed hypothermia with different severity. Equally lowest Core temperature were found in groups of L+R45 group and L+S45 group at the end of operation. The hypothermia is less severe in L45 group than L+R45 group and L+S45 group. Only minor core temperature decline were found in C group and L group at the end of operation. The hypothermia persisted 6 hours after operation in L45 group, L+R45 group and L+S45 group with different severity. The hypothermia persisted 12 hours after operation only in L+S45 group. (ii) Abnormal IPGTT values were found in L45 group, L+R45 group and L+S45 group at 12 hours after operation. The area under curve was increasing in these 3 groups gradually. (iii). Elevated levels of AST and CK were found in L group. Elevated levels of ALT, AST, Cr, BUN and CK were found in L45 group and L+R45 group with different severity. Abnormalities of ALT, AST, Cr, BUN, CK and electrolytes were the most significant in L+S45 group. (iv) The Abnormalities of ALT, AST, Cr, BUN, CK were correlated with AUC values in all rats. (v) Multiple regression analyze showed independent prediction effects of hypothermia and electrolyte abnormality on AUC values.Conclusions (i) Hypothermia and Hyperosmotic electrolyte abnormality in Laparotomy and Sea Water Emersion model are independent risk factors of IPGTT abnormality. (ii) IPGTT abnormality is positively correlated with organ injuries. (iii) Hypothermia and Hyperosmotic electrolyte abnormality might also be risk factors of organ injury in Laparotomy and Sea Water Emersion modelPart 3. The study on molecular mechanism of hepatic insulin resistance in a Laparotomy and Sea Water Emersion model after 12hObjective To explore possible cellular mechanism of glucose metabolic abnormality by evaluating possible changes of proteins and their phosphorylations in hepatic insulin signaling pathway in a Laparotomy and Sea Water Emersion model.Contents and methods 18 male SD rats were divided in to 3 groups according to received operations, the control group (C group, n=6), the laparotomy and exposure in air for 45min group (L45 group, n=6) and the laparotomy and sea water emersion for 45min group (L+S45 group, n=6). All rats were injected insulin or saline at 12 hours after operation, one minute later rats were sacrificed and liver samples were harvested. Western blot analysis were held to detect changes of hepatic insulin signaling pathway activity. Rats in each group were received insulin (5u/0.4ml) or saline (0.4ml) ? injection through portal vein. Liver samples were stored in liquid nitrogen for western blot analysis. The changes of IR, IRS-1, Serine and tyrosine phosphorylation of IRS-1 were examined.Results No changes of protein levels of IR and IRS-1 were found among all groups. Declines of insulin induced tyrosine phosphorylation of IRS-1 were found in L45 and L+S45 group, which was more obvious in L+S45 group. Increased serine phosphorylations of IRS-1 were found in L45 and L+S45 group, which was more obvious in L+S45 group.Conclusions (i) Glucose metabolic abnormality may not be related with changes of IR and IRS-1 levels in this model at 12 hours after operation. (ii) Declines of insulin induced tyrosine phosphorylation of IRS-1 suggested the impairment of hepatic insulin signal transduction with the post-receptor abnormality,insulin resistance maybe the cause of glucose intoleration.(iii) Increased serine phosphorylations of IRS-1 is possibly a molecular mechanisms of hepatic insulin resistance.
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