L-Carnitine inhibits the senescence-associated secretory phenotype of aging adipose tissue by JNK/p53 pathway.

Senescence-associated secretory phenotype (SASP) plays a role in aging adipose tissue dysfunction by directly promoting chronic inflammation. The JNK/p53 pathway was reported as a potential mechanism that mediates SASP. In this study, we investigated the effects of L-carnitine, an inhibitor of the JNK/p53 pathway in adipose tissue SASP and dysfunction. Young and aging rat were given L-carnitine by gavage. Next, we detected the senescence, cytokines expression, chronic inflammation and insulin resistance of adipose tissue. Additionally, JNK/p53 pathway was estimated. Our results show a significant increase expression of SASP components in the adipose tissue of aging rats compared to young rats. Further, we found that infiltration of immune cells and the expression of pro-inflammatory cytokines were enhanced in aging adipose tissue while insulin signaling activity was reduced in aging adipose tissue. Interestingly, L-carnitine markedly reduced the expression of SASP factors. L-Carnitine could significantly reduce chronic inflammation, improving insulin resistance. Further, L-carnitine inhibited SASP by inhibiting JNK/p53 pathway. L-Carnitine inhibited SASP by JNK/p53 pathway and attenuated adipose tissue dysfunction of aging.