α-Ketoglutaric acid ameliorates intervertebral disk degeneration by blocking the IL-6/JAK2/STAT3 pathway

Intervertebral disk degeneration (IVDD) is the major cause of low back pain. Alpha-ketoglutaric acid (alpha-KG), an important intermediate in energy metabolism, has various functions, including epigenetic regulation, maintenance of redox homeostasis, and antiaging, but whether it can ameliorate IVDD has not been reported. Here, we examined the impacts of long-term administration of alpha-KG on aging-associated IVDD in adult rats. In vivo and in vitro experiments showed that alpha-KG supplementation effectively ameliorated IVDD in rats and the senescence of nucleus pulposus cells (NPCs). alpha-KG supplementation significantly attenuated senescence, apoptosis, and matrix metalloproteinase-13 (MMP-13) protein expression, and it increased the synthesis of aggrecan and collagen II in IL-1 beta-treated NPCs. In addition, alpha-KG supplementation reduced the levels of IL-6, phosphorylated JAK2 and STAT3, and the nuclear translocation of p-STAT3 in IL-1 beta-induced degenerating NPCs. The effects of alpha-KG were enhanced by AG490 in NPCs. The underlying mechanism may involve the inhibition of JAK2/STAT3 phosphorylation and the reduction of IL-6 expression. Our findings may help in the development of new therapeutic strategies for IVDD.