糯谷猪解耦联蛋白3和心脏型脂肪酸结合蛋白在骨骼肌中的表达和定位

Expression and Localization of Uncoupling Protein 3 and Heart Fatty Acid-binding Protein in Skeletal Muscle Cells of Nuogu Pig

为了探索解耦联蛋白3(uncoupling protein 3,UCP3)和心脏型脂肪酸结合蛋白(heart fatty acid-bind-ing protein,H-FABP)对骨骼肌细胞中脂肪代谢的调节作用,采用RT-PCR和免疫组织化学方法,研究了地方猪品种糯谷猪骨骼肌细胞中UCP3和H-FABP基因的表达和细胞内定位,并与外二元杂交猪相比较,结果表明,糯骨猪的肌细胞及其细胞间隙较大,血清游离脂肪酸和肌内脂肪含量较高;但UCP3和H-FABP基因表达量和蛋白分布密度均较杂交猪低。说明糯谷猪肌细胞中UCP3和H-FABP的表达量较少,肌细胞中ATP的生成效率较高,对脂肪酸供能的依赖性较低,脂肪得以贮存。提示UCP3和H-FABP主要以蛋白量的变化参与猪骨骼肌细胞的脂肪代谢调节,从而影响地方猪种的肉质等性状。

Uncoupling protein 3（UCP3） and heart fatty acid-binding protein（H-FABP） are pivotal in the regulation of fat metabolism in skeletal muscle cells.Taking binary crossbreed pig of Large White pig and Landrace as control,the expression and localization of UCP3 and H-FABP genes and proteins are detected in the skeletal muscle cells by reverse transcription polymerase chain reaction（RT-PCR） and histological and immunohistochemistry methods.The results show that both of UCP3 and H-FABP are detected in the cytoplasm of muscle cells from Nuogu pig and crossbreed pig.Compared with crossbreed pig,however,the expressions of UCP3 and H-FABP in Nuogu pig breed are significantly lower based on the scan results of mean optical density（mOD） of positive pellets in the muscle cells.And the content of serum free fatty acids and intramuscular fat（IMF） of skeletal muscle are much higher in Nuogu pig breeds together with larger muscle cells and intracellular spaces.It sounds that the absorption of fatty acids from blood is less because of the lower H-FABP in muscle cells of Nuogu pig.And the production of adenosine triphosphate（ATP） is much more effective in Nuogu pig due to the lower expression of UCP3,which seems to be compensation to the less intake of fatty acids for energy supply in muscle cells of Nuogu pig.As a result,the excessive fatty acids would turn to synthesize triglyceride deposited in fat cells inside of muscle and fat tissue,which results in higher intramuscular fat（IMF） and backfat in Nuogu pig breed.It suggests that both of UCP3 and H-FABP genes and the expression in the muscle cells are contributed to the meat quality and backfat traits in Nuogu pig breed.