Gestational diabetes mellitus (GDM) is the most common metabolic disorder during pregnancy, which seriously affects the normal development of the fetus.Blood glucose control during pregnancy is associated not only with recent adverse outcomes such as preterm birth, macrosomia, hypoglycemia, neonatal respiratory distress syndrome, electrolyte disorders, heart malformations and intestinal disorders, but also with long-term results such as conti-nued impaired glucose tolerance, obesity, metabolic syndrome, mental illness and eye disease.Correct understanding of adverse effects of GDM on newborn infants in the short and long term and their related mechanisms as well as timely prevention and treatment measures can significantly improve the outcome of pregnancy.This paper will make a summary of these problems.

Objective To observe the effects of warm water bath active rewarming and passive rewarming on lung pathological injury and arterial blood gas of SD rats with hypothermia induced by prolonged seawater immersion.Methods One hundred male Sprague-Dawley rats were randomly divided into the normal control group (without any treatment) and the hypothermia group (seawater immersion at 20 ℃ for 24 h),The animals in the passive rewarming groups 1,2,3 and 4,each consisting of 10,had seawater immersion at 20 ℃for 24 h and received passive rewarming,and then they were respectively executed at 0,3,6 and 12 hours after rewarming,The animals in the active rewarming groups 1,2,3 and 4,each consisting of 10,underwent seawater immersion at 20 ℃ for 24 h and received active rewarming,and then they were sacrificed at 0,3,6and 12 hours after rewarming,Changes in lung pathology,arterial blood gas and other indicators were detected in all the animal groups.Results Both warm water bath active rewarming and passive rewarming all could help to restore lung injury and blood gas abnormality in rats with hypothermia induced by prolonged seawater immersion.Compared with that of the passive rewarming group [6 h:(7.6 ± 2.2) scores,12 h:(5.3 _± 1.3)scores],the recovery of lung pathological injury in warm water bath rewarming group was obviously better at 6 h(5.8 ± 1.2) scores and 12 h(3.8 ± 1.4) scores after rewarming,with statistical significance (P ＜ 0.05),and actual bicarbonate recovery was even better at 6 h after rewarming,also with statistical significance (P ＜0.05).Conclusions Compared with passive rewarming,warm water bath rewarming could significantly alleviate lung injury and arterial blood gas abnormality in hypothermic rats induced by prolonged seawater immersion,and it might produce even better effect on the prevention of rewarming-related acute respiratory distress syndrome.

Objective To investigate the dynamic changes in the nature of the pleural effusion via Light criteria in hypothermic rats induced by seawater immersion and analyze possible mechanism involved.Methods One hundred male Sprague-Dawley rats were randomly divided into the normal control group (without any treatment) and hypothermia group exposed to 20 ℃ seawater for 24 hours.Then,the hypothermia group was sub-divided into the passive rewarming groups 1,2,3 and 4 and warm water bath active rewarming groups 1,2,3 and 4,each consisting of 10 animals.The passive rewarming groups had passive rewarming after exposure to 20 ℃ seawater for 24 hours,while the active rewarming groups had warm water bath rewarming following exposure to 20 ℃ seawater for 24 hours.Then,all the animals in the sub-groups were executed 0,3,6 and 12 hours after rewarming.Serum,pleural effusion,total protein (TP) in pleural effusion,concentrations of lung homogenate lactate dehydrogenase (LDH) were measured,and Light criteria were calculated.Results There was no significant pleural effusion in the normal rats.LDH level in hypothermia-induced pleural effusion was higher than that in normal serum LDH,pleural effusion/total serum protein ratio (TPR) was lower than 0.5,and lactate dehydrogenase ratio (LDHR) was lower than 0.6.After rewarming,the amount of hypothermia-induced pleural effusion decreased gradually,while the levels of TPR and LDHR increased gradually.However,changes of LDH in pleural effusion were different with those in serum and lung homogenate.The warm water bath rewarming in the absorption of hypothermic pleural effusion was faster than passive rewarming,Warm water bath rewarming seemed to promote absorption of hypothermia-induced pleural effusion,but without statistical significance.Conclusions The 3 values of the pleural effusion criteria in hypothermic rats continuously increased following rewarming and reached the standards of effusion fluid,which did not necessarily reflect the seriousness of inflammatory pleural damage.The possible mechanism involved might be associated with the decrease of pleural effusion after rewarming,and water absorption by the body might be greater than protein absorption.

Objective To study the effects of active rewarming and passive rewarming on pulmonary oxidative stress and inflammatory response in rats with hypothermia induced by acute severe seawater immersion.Methods Sixty-four male healthy SD rats were randomly divided into the normal control group , the low temperature immersion group , the active rewarming group and the passive rewarming group . In accordance with rewarming time points , the two rewarming groups were further subdivided into the 2 h, 6 h and 12 h rewarming groups , each consisting of 8 animals.Effects of 2 different rewarming methods on lung oxygen free radicals ( MDA, SOD, GSH-PX) and serum inflammatory factors ( IL-6, IL-1β, TNF-a) were compared between the groups.Results (1) The MDA level [(2.84 ±0.46) nmol/mg pro] of the lungs in the 2 h active rewarming group was significantly higher than that of the 2 h passive rewarming group (P<0.05), and the MDA levels [(1.98 ±0.35) nmol/mg pro, (1.84 ±0.38) nmol/mg pro] of the 6 h and 12 h passive rewarming groups were slightly higher than those [(1.68 ±0.19) nmol/mg pro,(1.54 ±0.17) nmol/mg pro] of the 6 h and 12 h passive rewarming groups (P<0.05).(2) The SOD activity in the lungs of the 2 h and 6 h active rewarming groups was slightly higher than that of the 2 h and 6 h passive rewarming groups(P>0.05). The SOD activity in the lungs of the 12 h active rewarming group was higher than that of the 12 h passive rewarming group(P>0.05).(3) The GSH-PX activity in the lungs of the 2 h active rewarming group was slightly higher than that of the 2 h passive rewarming group(P>0.05).The GSH-PX activity in the lungs of the 6 h and 12 h active rewarming group was significantly higher than that of the 6 h and 12 h passive rewarming group(P<0.05).(4) The serum IL-1βand IL-6 levels of the 2 h passive rewarming group were obviously higher that those of the 2 h active rewarming group(P<0.05).The serum IL-1βand IL-6 levels in the 6 h and 12 h passive rewarming groups were slightly higher than those of the 6 h and 12 h active rewarming groups ( P<0.05).(5) The serum TNF-a levels of the 2 h, 6 h and 12 h passive rewarming groups were slightly higher that those of the 2 h, 6 h and 12 h active rewarming groups (P<0.05).Conclusion As compared with the active rewarming group , the activation of oxidative stress and inflammatory response in the passive rewarming group might worsen pulmonary lesion of the rats with hypothermia induced by acute severe seawater immersion .

Objective To establish hypothermia SD rat model induced by prolonged seawater immersion and to observe pathological damage to vital organs as well as certain important hematological parameters .Methods Twenty male adult Sprague-Dawley rats were randomly and equally divided into the normal control group and the hypothermia experimental group ( or simply the hypothermia group ) , each consisting of 10 rats.The control group was left there without any treatment , while the hypothermia group was immersed in artificial seawater at 20 ℃ for 24 hours to observe changes in vital signs of the rats during cold seawater immersion .At the end of the experiment , body temperature , general hematological parameters and pathological changes of vital organs were detected for further study .Results During the course of cold seawater immersion, the vital signs of the rats in the hypothermia group gradually worsened [( Heart rate before immersion (369 ±25.1) beats/min] vs (126.5 ±8.6) beats/min after immersion] (P<0.05).Respiratory rate before immersion was (92.8 ±7.2) times/min vs (43.9 ±3.8) times/min after immersion (P<0.05). Rectal temperature before immersion was (37.3 ±0.3) ℃vs (21.9 ±0.8) ℃ after immersion (P<0.05). After immersion, the blood routine detection indicated that hemoglobin level of the normal control group was (145.4 ±11.5) g/L, while that of the hypothermia group was (129.5 ±12.1) g/L ( P<0.05); neutrophil percentage of the normal control group was (18.3 ±3.5) ％, while that of the hypothermia group was (34.9 ± 6.1) ％(P<0.05).Prothrombin time (PT) of the normal control group was (11.42 ±2.36) s, while that of the hypothermia group was (17.86 ±2.41) s (P<0.05); APTT of the normal control group was (12.97 ± 2.41) s while that of the hypothermia group was (17.28 ±2.33) s (P <0.05).As for biochemical parameters, alanine aminotransferase (ALT) of the normal control group was (70.40 ±15.48) U/L, while that of the hypothermia group was (183.00 ±61.62) U/L (P<0.05); aspartate transaminase (AST) of the normal control group was (115.1 ±14.8) U/L, while that of the hypothermia group was (722.3 ±248.2) U/L (P<0.05);blood urea nitrogen (BUN) of the normal control group was (9.08 ±2.44) mmol/L, while that of the hypothermia group was (21.45 ±3.43) mmol/L (P<0.05);creatinine of the normal control group was (24.71 ±6.27) μmol/L, while that of the hypothermia group was (28.08 ±5.19) μmol/L (P<0.05);CK-MB of the normal control group was (451.00 ±266.53) U/L, while that of the hypothermia group was (2854.4 ±1089.6) U/L, with significant differences (P<0.05).Pathological detection indicated that there were lesions to various extents in all the vital organs , with the lesions to the lungs and stomach being most serious, and pleural effusion induced by hypothermia was also present .Conclusion The SD rat model of hypothermia induced by prolonged seawater immersion was successfully established for subsequent studies .Our present study showed that lungs and stomach were important target organs involved in prolonged seawater immersion.

Objective To observe changes in blood biochemistry and coagulation function before and after warm water bath rewarming in SD rats with hypothermia induced by prolonged seawater immersion . Methods One hundred male Sprague-Dawley rats were randomly divided into the normal control group ( the NC group, without any treatment ) and the hypothermia group ( the HT group, exposed to seawater immersion at 20 ℃for 24 hours).The passive rewarming sub-groups (the pR group 1, 2, 3 and 4, n=10) (exposed to seawater immersion at 20 ℃for 24 hours +passive rewarming ) were respectively executed after rewarming at hour 0, hour 3, hour 6, and hour 12).The warm-water bath rewarming sub-groups (the wR group 1, 2, 3 and 4, n=10 ) ( exposed to seawater immersion at 20 ℃ for 24 hours +warm-water bath rewarming ) were respectively executed after rewarming at hour 0, hour 3, hour 6, and hour 12).Blood samples were taken from abdominal aorta for biochemical and coagulation detection .Results Zero to 3 hours after warm water bath rewarming , important parameters of hepatic and renal functions , as well as myocardial enzymes in the SD rats with hypothermia induced by prolonged seawater immersion remained at high levels or even increased to some extent.Only after 6 hours after rewarming , the above-mentioned parameters dropped considerably .However, coagulation indicators began to decline immediately after rewarming , and as compared with the passive rewarming , warm water bath rewarming could produce obviously better effects on the alleviation of abnormal hepatic and renal functions, as well as myocardial enzyme parameters (P<0.05).Conclusion Warm water bath rewarming could produce better effects on the recovery of serum biochemical parameters in rats with hypothermia induced by prolonged seawater immersion when compared with those of passive rewarming .

Objective To observe the effects of warm water bath active rewarming and passive rewarming on lung pathological injury and arterial blood gas of SD rats with hypothermia induced by prolonged seawater immersion.Methods One hundred male Sprague-Dawley rats were randomly divided into the normal control group (without any treatment) and the hypothermia group (seawater immersion at 20 ℃ for 24 h),The animals in the passive rewarming groups 1,2,3 and 4,each consisting of 10,had seawater immersion at 20 ℃for 24 h and received passive rewarming,and then they were respectively executed at 0,3,6 and 12 hours after rewarming,The animals in the active rewarming groups 1,2,3 and 4,each consisting of 10,underwent seawater immersion at 20 ℃ for 24 h and received active rewarming,and then they were sacrificed at 0,3,6and 12 hours after rewarming,Changes in lung pathology,arterial blood gas and other indicators were detected in all the animal groups.Results Both warm water bath active rewarming and passive rewarming all could help to restore lung injury and blood gas abnormality in rats with hypothermia induced by prolonged seawater immersion.Compared with that of the passive rewarming group [6 h:(7.6 ± 2.2) scores,12 h:(5.3 _± 1.3)scores],the recovery of lung pathological injury in warm water bath rewarming group was obviously better at 6 h(5.8 ± 1.2) scores and 12 h(3.8 ± 1.4) scores after rewarming,with statistical significance (P ＜ 0.05),and actual bicarbonate recovery was even better at 6 h after rewarming,also with statistical significance (P ＜0.05).Conclusions Compared with passive rewarming,warm water bath rewarming could significantly alleviate lung injury and arterial blood gas abnormality in hypothermic rats induced by prolonged seawater immersion,and it might produce even better effect on the prevention of rewarming-related acute respiratory distress syndrome.

Objective To investigate the dynamic changes in the nature of the pleural effusion via Light criteria in hypothermic rats induced by seawater immersion and analyze possible mechanism involved.Methods One hundred male Sprague-Dawley rats were randomly divided into the normal control group (without any treatment) and hypothermia group exposed to 20 ℃ seawater for 24 hours.Then,the hypothermia group was sub-divided into the passive rewarming groups 1,2,3 and 4 and warm water bath active rewarming groups 1,2,3 and 4,each consisting of 10 animals.The passive rewarming groups had passive rewarming after exposure to 20 ℃ seawater for 24 hours,while the active rewarming groups had warm water bath rewarming following exposure to 20 ℃ seawater for 24 hours.Then,all the animals in the sub-groups were executed 0,3,6 and 12 hours after rewarming.Serum,pleural effusion,total protein (TP) in pleural effusion,concentrations of lung homogenate lactate dehydrogenase (LDH) were measured,and Light criteria were calculated.Results There was no significant pleural effusion in the normal rats.LDH level in hypothermia-induced pleural effusion was higher than that in normal serum LDH,pleural effusion/total serum protein ratio (TPR) was lower than 0.5,and lactate dehydrogenase ratio (LDHR) was lower than 0.6.After rewarming,the amount of hypothermia-induced pleural effusion decreased gradually,while the levels of TPR and LDHR increased gradually.However,changes of LDH in pleural effusion were different with those in serum and lung homogenate.The warm water bath rewarming in the absorption of hypothermic pleural effusion was faster than passive rewarming,Warm water bath rewarming seemed to promote absorption of hypothermia-induced pleural effusion,but without statistical significance.Conclusions The 3 values of the pleural effusion criteria in hypothermic rats continuously increased following rewarming and reached the standards of effusion fluid,which did not necessarily reflect the seriousness of inflammatory pleural damage.The possible mechanism involved might be associated with the decrease of pleural effusion after rewarming,and water absorption by the body might be greater than protein absorption.

Objective To study the effects of active rewarming and passive rewarming on pulmonary oxidative stress and inflammatory response in rats with hypothermia induced by acute severe seawater immersion.Methods Sixty-four male healthy SD rats were randomly divided into the normal control group , the low temperature immersion group , the active rewarming group and the passive rewarming group . In accordance with rewarming time points , the two rewarming groups were further subdivided into the 2 h, 6 h and 12 h rewarming groups , each consisting of 8 animals.Effects of 2 different rewarming methods on lung oxygen free radicals ( MDA, SOD, GSH-PX) and serum inflammatory factors ( IL-6, IL-1β, TNF-a) were compared between the groups.Results (1) The MDA level [(2.84 ±0.46) nmol/mg pro] of the lungs in the 2 h active rewarming group was significantly higher than that of the 2 h passive rewarming group (P<0.05), and the MDA levels [(1.98 ±0.35) nmol/mg pro, (1.84 ±0.38) nmol/mg pro] of the 6 h and 12 h passive rewarming groups were slightly higher than those [(1.68 ±0.19) nmol/mg pro,(1.54 ±0.17) nmol/mg pro] of the 6 h and 12 h passive rewarming groups (P<0.05).(2) The SOD activity in the lungs of the 2 h and 6 h active rewarming groups was slightly higher than that of the 2 h and 6 h passive rewarming groups(P>0.05). The SOD activity in the lungs of the 12 h active rewarming group was higher than that of the 12 h passive rewarming group(P>0.05).(3) The GSH-PX activity in the lungs of the 2 h active rewarming group was slightly higher than that of the 2 h passive rewarming group(P>0.05).The GSH-PX activity in the lungs of the 6 h and 12 h active rewarming group was significantly higher than that of the 6 h and 12 h passive rewarming group(P<0.05).(4) The serum IL-1βand IL-6 levels of the 2 h passive rewarming group were obviously higher that those of the 2 h active rewarming group(P<0.05).The serum IL-1βand IL-6 levels in the 6 h and 12 h passive rewarming groups were slightly higher than those of the 6 h and 12 h active rewarming groups ( P<0.05).(5) The serum TNF-a levels of the 2 h, 6 h and 12 h passive rewarming groups were slightly higher that those of the 2 h, 6 h and 12 h active rewarming groups (P<0.05).Conclusion As compared with the active rewarming group , the activation of oxidative stress and inflammatory response in the passive rewarming group might worsen pulmonary lesion of the rats with hypothermia induced by acute severe seawater immersion .

Objective To establish hypothermia SD rat model induced by prolonged seawater immersion and to observe pathological damage to vital organs as well as certain important hematological parameters .Methods Twenty male adult Sprague-Dawley rats were randomly and equally divided into the normal control group and the hypothermia experimental group ( or simply the hypothermia group ) , each consisting of 10 rats.The control group was left there without any treatment , while the hypothermia group was immersed in artificial seawater at 20 ℃ for 24 hours to observe changes in vital signs of the rats during cold seawater immersion .At the end of the experiment , body temperature , general hematological parameters and pathological changes of vital organs were detected for further study .Results During the course of cold seawater immersion, the vital signs of the rats in the hypothermia group gradually worsened [( Heart rate before immersion (369 ±25.1) beats/min] vs (126.5 ±8.6) beats/min after immersion] (P<0.05).Respiratory rate before immersion was (92.8 ±7.2) times/min vs (43.9 ±3.8) times/min after immersion (P<0.05). Rectal temperature before immersion was (37.3 ±0.3) ℃vs (21.9 ±0.8) ℃ after immersion (P<0.05). After immersion, the blood routine detection indicated that hemoglobin level of the normal control group was (145.4 ±11.5) g/L, while that of the hypothermia group was (129.5 ±12.1) g/L ( P<0.05); neutrophil percentage of the normal control group was (18.3 ±3.5) ％, while that of the hypothermia group was (34.9 ± 6.1) ％(P<0.05).Prothrombin time (PT) of the normal control group was (11.42 ±2.36) s, while that of the hypothermia group was (17.86 ±2.41) s (P<0.05); APTT of the normal control group was (12.97 ± 2.41) s while that of the hypothermia group was (17.28 ±2.33) s (P <0.05).As for biochemical parameters, alanine aminotransferase (ALT) of the normal control group was (70.40 ±15.48) U/L, while that of the hypothermia group was (183.00 ±61.62) U/L (P<0.05); aspartate transaminase (AST) of the normal control group was (115.1 ±14.8) U/L, while that of the hypothermia group was (722.3 ±248.2) U/L (P<0.05);blood urea nitrogen (BUN) of the normal control group was (9.08 ±2.44) mmol/L, while that of the hypothermia group was (21.45 ±3.43) mmol/L (P<0.05);creatinine of the normal control group was (24.71 ±6.27) μmol/L, while that of the hypothermia group was (28.08 ±5.19) μmol/L (P<0.05);CK-MB of the normal control group was (451.00 ±266.53) U/L, while that of the hypothermia group was (2854.4 ±1089.6) U/L, with significant differences (P<0.05).Pathological detection indicated that there were lesions to various extents in all the vital organs , with the lesions to the lungs and stomach being most serious, and pleural effusion induced by hypothermia was also present .Conclusion The SD rat model of hypothermia induced by prolonged seawater immersion was successfully established for subsequent studies .Our present study showed that lungs and stomach were important target organs involved in prolonged seawater immersion.