Objective:To investigate the effects of different phototherapy intensities on the levels of malondialdehyde, a peroxidation product of intralipid, vitamin C and vitamin E in parenteral nutrition for premature infants.Methods:The parenteral nutrition for premature infants was prepared under strict aseptic condition and was divided into four groups based on different phototherapy intensities in simulated clinical settings, which were indoor light group, single-, double-, and three-sided phototherapy group. According to whether the nutrient solution shielded for light or not, each group was further divided into two subgroups: exposure or non-exposure group. The levels of malondialdehyde, vitamin C and vitamin E in all groups before phototherapy and 6, 12, 18, and 24 h after phototherapy were measured. Ten samples of parenteral nutrient solutions were prepared for each group, of which 2 ml were extracted for test at different time points. Repeated measurement analysis of variance was used for data analysis and the results were adjusted using Greenhouse-Geisser method if failed in Mauchly sphere test.Results:With the increase of phototherapy time, the malondialdehyde level increased in the exposure and the non-exposure subgroups in the one-sided phototherapy group [before phototherapy: (3.777±0.112) vs (3.746±0.141) nmol/ml; phototherapy for 6 h: (3.808±0.122) vs (3.715±0.145) nmol/ml; 12 h: (4.546±0.138) vs (4.507±0.136) nmol/ml; 18 h: (6.116±0.151) vs (5.239±0.156) nmol/ml; 24 h: (7.569±0.136) vs (5.300±0.200) nmol/ml; all P<0.05], but the level of vitamin C [before phototherapy: (62.507±0.205) vs (62.341±0.144)μg/ml; phototherapy for 6 h: (51.211±0.086) vs (58.128±0.076) μg/ml; 12 h: (43.288±0.084) vs (55.351±0.050) μg/ml; 18 h: (35.758±0.113) vs (51.215±0.093) μg/ml; 24 h: (33.473±0.075) vs (48.473±0.080)μg/ml] and vitamin E decreased [before phototherapy: (4.101±0.132) vs (4.084±0.141) μg/ml; phototherapy for 6 h: (3.761±0.119) vs (3.904±0.075) μg/ml; 12 h: (3.654±0.092) vs (3.729±0.087) μg/ml; 18 h: (3.385±0.102) vs (3.582±0.119) μg/ml; 24 h: (3.313±0.127) vs (3.438±0.113) μg/ml, all P<0.05]. The same situation was also observed in indoor light group, double-, and three-sided phototherapy groups. The malondialdehyde level at different time in the exposure subgroups were higher but the vitamin C and vitamin E levels were lower than those in the non-exposure subgroups, regardless of the phototherapy intensities (all P<0.001). (2) The analysis of all exposure phototherapy subgroups showed that the higher the intensity of light therapy, the higher the malondialdehyde level, and the lower the level of vitamin C and vitamin E, with statistical significance differences in any pairwise comparison. Analysis of all non-exposure subgroups showed statistically significant differences in the malondialdehyde level in any pairwise comparison (all P<0.05) except for the comparison between indoor light group and single-sided phototherapy group ( F=2.383. P=0.140). Moreover, the greater the phototherapy intensities, the lower vitamin C level, with statistically significant differences in any pairwise comparison. And statistical significance differences were observed in the vitamin E level in any pairwise comparison (all P<0.05) except for the comparison between double- and three-sided phototherapy groups ( F=1.358, P=0.259). Conclusions:Phototherapy can increase the malondialdehyde level in parenteral nutrient solution for premature infants and the degree of intralipid peroxidation, but can also lead to vitamin C and vitamin E loss in the parenteral nutrient and weaken its antioxidant capacity.

Objective To study the effects of the Notch ligands Dlk1 and recombinant human nucleu factorκB (Jagged1) on the proliferation and transdifferentiation of the type Ⅱ alveolar epithelial cells when the Notch signaling pathway activated.Methods The primary type Ⅱ alveolar epithelial cells (AEC Ⅱ) cultured with recombinant protein Dlk1 and recombinant human nucleu factor-κB (rhNF-κB) (activator of Jagged1),respectively,and then cultured with DMEM (containing 120 mL/L FBS) as controls.Proliferation and differentiation conditions of the AEC Ⅱ were observed at 48 h,72 h,96 h time point by the light microscope and electron microscopes separately.Cell number was counted with hemacytometer; the proliferation rate was measured by methyl thiazolyl tetrazolium (MTT) ; Immunofluorescence double standard method was used to detect the AEC Ⅱ specific surfactant protein C (SP-C) and AEC Ⅰ specific protein aquaporin5 (AQPS) ;the expression of SP-C,AQPS,Dlk1,Jagged1,Notch1 and Hes1 mRNA were detected by real time-PCR.Results The cell population and proliferation:compared with control group,AEC Ⅱ proliferation was promoted in the Dlk1 group [cell numbers (× 109/L) 9.05 ± 0.45 vs 7.95 ± 0.65,11.68 ± 0.43 vs 8.68 ± 0.52,11.55 ± 0.17 vs 8.73 ± 0.48,all P ＜ 0.05 ; MTT results (value A) 0.699 ± 0.050 vs 0.462 ± 0.080,0.912 ± 0.080 vs 0.535 ±0.040,0.726 ±0.050 vs 0.540 ±0.020,all P ＜0.05] and decelerated AEC Ⅱ transdifferentiation into AEC Ⅰ ; while AEC Ⅱ proliferation was inhibited in rhNF-κB group [cell numbers (× 109/L) 4.95 ± 0.33 vs 7.95 ± 0.65,4.73 ±0.71 vs 8.68 ± 0.52,4.04 ± 0.11 vs 8.73 ± 0.48,all P ＜ 0.05; MTT results (value A) 0.398 ± 0.030 vs 0.462 ± 0.080,0.402 ± 0.070 vs 0.535 ± 0.040,0.380 ± 0.110 vs 0.540 ± 0.020,all P ＜ 0.05] and accelerated AEC Ⅱ transdifferentiation into AEC Ⅰ.One-Way ANOVA showed that the difference among the 3 groups had statistical significance (cell numbers:F =486.73,P =0.02; cell proliferation:F =37.16,P =0.02).The mRNA expression:compared with control group,the expression of SP-C mRNA of Dlk1 group was significantly higher (P ＜ 0.05) while the expression of AQP5 mRNA was remarkably lower and delayed (P ＜ 0.05),the expression of Jagged1 mRNA was weak or little,Dlk1 and Notch1 mRNA were up-regulated (P ＜ 0.05),and the Hes1 mRNA was reduced (P ＜ 0.05) ; the expression of SP-C mRNA of rhNF-κB group was significantly reduced (P ＜ 0.05),while the AQP5 mRNA expressed ahead of time and increased (P ＜ 0.05),Jagged1,Hes1 and Notch1 mRNA were higher (P ＜ 0.05),and the Dlk1 mRNA was weak.One-Way ANOVA showed that the difference in the expressions of SP-C,AQP5,D1k1,Jagged1,Hes1 and Notch1 mRNA among the 3 groups had staistical significance (F =96.80,P =0.01 ; F =82.55,P =0.01 ; F =269.80,P=0.00;F =312.34,P =0.00;F =169.17,P =0.01;F =19.85,P =0.02).Conclusions There are varied effects on proliferation and differentiation of the AEC Ⅱ when the Notch signaling is activated by different ligands:Dlk1 promoted proliferation and inhibited differentiation,while Jagged1 inhibited proliferation and promoted transdifferentiation.