To 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.
METHODS: Forty-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-L1 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.
RESULTS: The 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).
CONCLUSION: