| A total of fifteen pigs (Duroc×Landrace×Yorkshire) weighted at 1kg,20kg,40kg,60kg and 90kg were used to study the tissue-specific expression, the developmental expression of FoxO1 and SOCS3 genes, and relationships between FoxO1 and SOCS3 mRNA levels and adipose deposition. The effects of RES on expression of porcine preadipocytes FoxO1 and SOCS3 mRNA levels were also studied. Results are as follows:1. The special primers for FoxO1,SOCS3 and 18S rRNA were designed respectively according to the reported porcine gene sequences. The cloned sequence analysis suggested that the gene homology of fragments obtained in this study were 98%,100% and 100% compared with that of the reported cDNA sequence (DQ243692,AY785556 and AY265350) of pig in Genbank. In addition, the optimal semi-quantitative RT-PCR methods were constructed to detect FoxO1 and SOCS3 mRNA levels.2. Pigs weighed at 20kg were killed, and omental adipose tissue, subcutaneous adipose tissue, peritoneal adipose tissue, brain, heart, liver, kidney, spleen, skeletal muscle, duodenum, and pancreas tissues were collected to study the tissue-specific gene expression of FoxO1 and SOCS3. The results showed that the FoxO1 mRNA level in a higher level was detected in liver, omental adipose tissue and skeletal muscle, at a moderate level in spleen, heart, kidney and pancreas, and at a low level in brain, subcutaneous adipose tissue, duodenum and peritoneal adipose tissue. The SOCS3 mRNA had a higher level in heart and peritoneal adipose tissue, and lower was detected in brain and duodenum.3. Total fifteen pigs(three pigs per body weight) weighed at 1,20,40,60 and 90kg were slaughtered for sampling. Omental adipose tissue, peritoneal adipose tissue and subcutaneous adipose tissue were collected, weighed, and stored, for determination of developmental FoxO1 and SOCS3 mRNA levels and relationships with adipose deposition. The results showed that a significantly positive correlation between the FoxO1 mRNA levels in the Omental adipose tissue and the fat deposition rate was found from 1kg to 90kg (r=0.837,P<0.05). The SOCS3 mRNA levels in the three adipose tissues increased with body weight, and there were a positive correlation between the SOCS3 mRNA levels in omental adipose tissue(r=0.882,P<0.01) and subcutaneous adipose tissue(r=0.976,P<0.05) and the adipose deposition rate.4. Piglet's primary preadipocytes were cultured and treated with Oμmol/L (control group), 40μmol/L,80μmol/L and 120μmol/L RES. The results demonstrated that RES significantly inhibited proliferation and differentiation of pig preadipocytes. The proliferation of preadipocyte was determined by MTT spectrophotometry, and 40μmol/L,80μmol/L and 120μmol/L RES significantly decreased the optical density by 22.30%(P<0.05),36.82%(P<0.01) and 42.50%(P<0.01) respectively when compared with control group. Determined the optical density after oil red 0 staining was used to investigate the differentiation of preadipocyte. Oil red 0 chromatometry showed that the optical density was significantly decreased by 25.74%(P<0.05), 60.78%(P<0.01) and 39.71%(P<0.01) respectively when treated with 40μmol/L, 80μmol/L and 120μmol/L RES. RES down-regulated the expression of FoxO1 mRNA levels, and showed a dose-dependent effect. After 24 hours,80μmol/L RES and 120μmol/L RES significantly decreased the expression of FoxO1 mRNA levels by 34.30%(P<0.05) and 42.47%(P<0.01) as compared with control group. In addition, RES up-regulated the expression of SOCS3 mRNA levels. Treated 24 hours and 48 hours,80μmol/L RES significantly decreased the expression of SOCS3 mRNA levels by 32.53%(P<0.05) and 46.71%(P<0.01) as compared with control group.5. The present data indicated RES can prevent preadipocytes differentiation and decrease adipogenesis, which may be in part associated with its effect on decreasing the expression of FoxO1 mRNA and increasing the expression of SOCS3 mRNA.
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