ObjectiveTo investigate the effect of burn on the fat metabolism by observing the effect of burn serum on the proliferation and adipose differentiation of 3T3-L1 preadipocytes. MethodsForty-eight male Sprague Dawley rats were randomly divided into sham burn group and burn at 1, 4, 7, 14, and 21 days groups, 8 rats in each group. The rats in burn groups were made the full-thickness thermal burns comprising 30% total body surface area. At 1, 4, 7, 14, and 21 days after burn, the serum of burn rats was collected. The rats in sham burn group were not treated as normal control. The proliferation activity of 3T3-Ll cells was detected using MTT method after treated by normal and burn serum. The burn serum having the highest proliferation inhibitory effect was chosen for subsequent study. The growth of 3T3-L1 cells in normal serum group (group A), burn serum group (group B), normal serum and adipogenic induction group (group C), burn serum and adipogenic induction group (group D) was observed using inverted microscope. After 7 days of treatment, the adipocytes was stained by oil red O and the absorbance (A) value was measured. The mRNA and protein levels of preoxisome proliferator-activated receptor γ (PPAR-γ) and lipoprotein lipase (LPL) were detected by real-time quantitative PCR and Western blot. ResultsThe proliferation ability of 3T3-L1 cells was significantly reduced in the group treated by 4-or 7-day burn serum (P<0.05), especially 7-day burn serum treatment group (P<0.05). Under inverted microscope, the cell morphology in group A and group B had no obvious change, but a large number of fat cells were observed in group C and a few were observed in group D. The positive or weak positive oil red O staining was observed in group C or group D, respectively. The cell counting and A value were significantly higher in group A than in group B, and in group C than in group D (P<0.05). The mRNA level of PPAR-γ in group B was significantly reduced when compared with that in group A (P<0.05). No significant difference was found in LPL mRNA levels and protein levels of PPAR-γ and LPL between group A and group B (P>0.05). The mRNA and protein levels of PPAR-γ and LPL were significantly attenuated in group D when compared with those in group C (P<0.05). ConclusionThe adipose differentiation of 3T3-L1 preadipocytes can be significantly reduced after treated by 7-day burn serum of rat.
ObjectiveTo investigate the effect of burn on brown adipose tissue (BAT) in BALB/c mice. MethodsForty 3-4 months old male BALB/c mice with initial body weight of (20±3) g were randomly divided into control group and burn group (n=20).BALB/c mice in burn group were subjected to a 30% total body surface area (TBSA) full-thickness thermal injury.BALB/c mice in control group were not treated.The body weight and temperature were observed before and after burn.At 7 days after burn,morphological changes of white adipose tissue (WAT) and BAT were observed,the gene and protein expressions of uncoupling protein 1 (UCP-1) were detected. ResultsThere was no significant difference in the body weight and body temperature before burn (P>0.05).At 1,2,3,and 4 weeks after burn,the body weight was significantly lower in burn group than in control group (P<0.05).At 1,2,3,and 7 days after burn,the body temperature was significantly higher in burn group than in control group (P<0.05).At 7 days after burn,the weight of WAT was significantly reduced,and the weight of BAT was significantly increased in burn group (P<0.05); WAT and BAT cells became smaller,cell number increased,the cytoplasm and mitochondria appeared as compact.The UCP-1 gene and protein expressions of burn group were significantly higher than those of control group (P<0.05). ConclusionBAT plays an important role in burn-induced hypermetabolism.