Rno-miR-130b Attenuates Lipid Accumulation Through Promoting Apoptosis and Inhibiting Differentiation in Rat Intramuscular Adipocytes

Our previous studies have shown that miR-130b can significantly inhibit subcutaneous fat deposition in pigs. This study aims to further investigate its effect on lipid accumulation at early-stage (24 and 48 h) and late-stage (7 d) adipogenic differentiation and to clarify potential mechanisms using primary rat intramuscular preadipocytes (IMAs). Results showed that at 24 h and 48 h, miR-130b overexpression significantly reduced lipid deposition by inhibiting proliferation and inducing apoptosis. Furthermore, miR-130b overexpression significantly inhibited the expression of cell cycle and apoptosis marker genes. Specifically, the mRNA expression of <i>Ccnd1</i> tended to decrease, while the BCL2 protein level was significantly decreased at 48 h. In contrast, miR-130b inhibition significantly increased the BCL2 protein level. At 7 d, the miR-130b mimic significantly decreased intracellular TG content and tended to decrease <i>Hsd11b1</i> mRNA expression while significantly promoting <i>Lpl</i> mRNA expression. Additionally, the miR-130b mimic significantly increased the CASP3 protein level and tended to decrease the BCL2 protein level. In conclusion, our data indicated for the first time that miR-130b could reduce lipid deposition in rat IMAs through different mechanisms: at the early stage of differentiation by inhibiting proliferation and promoting apoptosis and at the late stage by inhibiting adipogenic differentiation, promoting lipid hydrolysis, and promoting apoptosis.