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Objective:To study the effects of gender on clinical outcomes of extremely low birth weight infants (ELBWI) and to analyze the risk factors of mortality.Methods:From January 2011 to December 2020, ELBWI (birth weight <1 000 g) admitted to the Neonatology Department of our hospital were retrospectively studied. The infants were assigned into the male group and the female group. Incidences of major complications, survival rate and mortality rate were compared between the two groups. The infants were also assigned into survival group and death group according to their clinical outcomes. Binary multivariate unconditional Logistic regression was used to analyze the risk factors of mortality in ELBWI.Results:A total of 637 ELBWI cases were included. 311 cases were in the male group with a survival rate of 57.9% (180/311) and 326 cases were in the female group with a survival rate of 57.4% (187/326). The incidences of neonatal respiratory distress syndrome (RDS), bronchopulmonary dysplasia (BPD), pulmonary hemorrhage and severe intraventricular hemorrhage (IVH) in the male group were significantly higher than the female group ( P<0.05). Significant increases of survival rate existed for both groups year by year ( P<0.01).No significant differences existed in survival rate, mortality rate of infants receiving proactive treatment and mortality rate of infants withdrawing treatment between the two groups ( P>0.05). Multivariate unconditional Logistic regression analysis showed that withdrawing treatment ( P<0.01) and pulmonary hemorrhage ( P<0.05) were associated with increased risks of mortality. Conclusions:Male ELBWI have higher risks of RDS, BPD and severe IVH than female ELBWI. Withdrawing treatment and pulmonary hemorrhage are common risk factors of mortality for both male and female ELBWI.
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Objective To investigate the effect of docosahexaenoic acid (DHA) on the body weight growth and lipid metabolism of neonatal rats during lactation.Methods The specific pathogen free Sprague-Dawley neonatal rats were randomly assigned into 4 groups (high-dose group,medium-dose group,low-dose group and control group) by random number table method.The rats in 3 experiment groups received intragastric administration with DHA 600 mg/kg,300 mg/kg and 100 mg/kg,respectively,while the control group were given 9 g/L saline,totally for 21 days.Body weight was monitored and compared among groups on postnatal day 1,7,14 and 21.And body weight growth rates at each time point were calculated.The serum concentrations of high density lipoprotein cholesterol (HDL-C),low density lipoprotein cholesterol(LDL-C),triglyceride (TG) and total cholesterol were measured and compared at 6-week and 8-week ages.The pathological and histological changes in the heart,the large vessel and the liver were observed at same time.Results The mean body weight of the neonatal rats were significantly different among 4 groups on postnatal day 7,14 and 21 (F =17.334,4.159,6.485,all P ＜ 0.01).Comparisons were made between every 2 groups,the low-dose group was higher than the control group on postnatal day 7 [(21.60 ±0.89) g vs.(18.57 ± 0.76) g] and day 21 [(58.52 ±6.62) g vs.(53.01 ± 11.75) g];the medium-dose group was lower than the control group on postnatal day 7 [(14.23 ±0.49) g vs.(18.57 ±0.76) g] and lower than the low-dose group on postnatal day 21 [(52.47 ±8.18) g vs.(58.52 ±6.62) g];the high-dose group was lower than the low-dose group on postnatal day 7[(16.13 ± 1.02) g vs.(21.6 ±0.89) g],and it was lower than the control group and the low-dose group on postnatal day 14[(31.69 ± 1.77) g vs.(37.60 ± 1.32) g and (36.24 ±0.84) g],and lower than all the other 3 groups on postnatal day 21 [(45.9 ± 13.17) g vs.(53.01 ± 11.75) g,(58.52 ±6.62) g and (52.47 ±8.18) g];all the differences above were statistically significant (all P ＜ 0.05).During the first and the second week after birth,there were significant differences in the mean body weight growth rate among 4 groups (F =8.369,8.331,all P ＜ 0.01),but there was no significant difference during the third week (F =0.603,P ＞ 0.05).Compared with 2 groups,the mean body weight growth rate of the low-dose group was higher than that of the control group in the first week [(184.96 ± 63.16) ％ vs.(141.02 ± 72.07) ％],but which was lower than that of the control group in the second week [(72.60 ± 35.37) ％ vs.(103.20 ± 40.11) ％];the medium-dose group was lower than the low-dose group at the first week [(116.78 ± 51.59) ％ vs.(184.96 ± 63.16)％],but higher than the low-dose group and lower than the control group at the second week[(139.93 ± 67.4) ％ vs.(72.60 ± 35.37) ％ and (103.20 ± 40.11) ％];the high-dose group was lower than the low-dose group in the first week [(137.33 ± 34.42) ％ vs.(184.96 ± 63.16) ％] and lower than that of the medium-dose group in the second week [(98.22 ± 65.86) ％ vs.(139.93 ± 67.4) ％];all these differences were statistically significant (all P ＜ 0.05).At 6 weeks of age,the mean serum concentrations of total cholesterol,TG and LDL-C were not significandy different (F =1.899,1.450,2.581,all P ＞ 0.05) among 4 groups,but the mean concentration of HDL-C was statistically different (F =7.801,P ＜ 0.01).In detail,the mean concentration of HDL-C in medium-dose group was higher than that of the control group,the low-dose group and the high dose group [(1.66 ± 0.08) mmol/L vs.(0.97 ± 0.16) mmol/L,(1.20 ± 0.09) mmol/L and (0.82 ± 0.09) mmol/L,all P ＜ 0.05],and which in the high-dose group was lower than that in the low-dose group (P ＜ 0.05).At 8-week age,the mean serum concentrations of HDL-C,LDL-C and total cholesterol were not significantly different among 4 groups (F =0.935,0.300,1.299,all P ＞ 0.05),but the mean concentration of TG was significantly different (F =2.875,P ＜ 0.05).The mean concentration of TG in the medium-dose group was lower than that in the control group [(0.98 ± 0.11) mmol/L vs.(1.36 ± 0.09) mmol/L,P ＜ 0.05].There were 5 (15.62％) neonatal rats in the high-dose group which were found to have adipose tissue accumulation around the large vessel walls and the heart and were confirmed by histological examination.The liver cells in these rats were found to have mild fatty changes.No similar changes were found in the other groups.Conclusions Neonatal rats supplemented with DHA during lactation can affect their body weight growth and lipid metabolism.Supplemented with high dose may bring risks,while moderate dose may bring benefits.
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Objective To study the influence of postnatal high protein feeding on learning and memory abilities of preterm rats.Methods After weaning,the SD offspring were divided into 6 groups randomly according random digits table:preterm standard protein group (group A),term standard protein group (group B),preterm low protein group (group C),term low protein group (group D),preterm high protein group (group E),and term high protein group (group F),with 34 rats in each group.Starting from 22 days of age,the standard protein group,low-protein group and the high-protein group were respectively fed with a standard protein diet (containing 18％ protein),low-protein diet (containing 8％ protein) and a high-protein diet (containing 30％ protein) until the end of experiment.Within each group,the rats were respectively tested in 6 weeks and 8 weeks.Morris water maze task was performed to assess the learning and memory abilities of the premature rats.Results 1.Directional navigation experiments:(1) At the age of 6 weeks,the escape latencies to find the platform were shortened with increased training times for full-term rats.The escape latencies of the premature rats did not change significantly on the third and fourth day of the experiment.(2) At the age of 8 weeks,the escape latencies to find the platform were shortened with increased training time for all of the rats.2.Probe trial test:(1)At the age of 6 weeks,premature rats spent significantly less time in target quadrant than full-time rats.And the percent age of traveled distance in target quadrant of premature rats was significantly less than full term rats (P ＜ 0.05).(2) At the age of 8 weeks,group E [(68.48 ± 20.65) s] spent significantly greater time in target quadrant than group A and group C [group A(52.41 ± 11.24) s,group C (49.54 ± 11.04) s].And the percent age of traveled distance in target quadrant of group E [(36.56 ± 10.44) ％] were significantly higher than group A and group C [group A (29.83 ± 8.33) ％,group C (26.97 ± 5.41) ％] (P ＜ 0.05).(3) At the age of 8 weeks,group E spent time in target quadrant and the percent of traveled distance in target quadrant [(68.48 ± 20.65) s,(36.56 ±10.44)％] were higher than group F [(61.29 ± 16.27) s,(35.71 ±6.61)％],but there was no significant difference (P ＞ 0.05).Conclusions In the early growth and development process of the brain,premature birth may seriously affect early brain functions in rats,and the learning and cognitive abilities of the premature rats are worse than full-term rats.In the subsequent process of growth and development,after a long time of high protein nutritional intake,the learning and cognitive abilities of the premature rats can be restored and they can catch up with full-term rats.