The Role of N-Acetyltransferase 8 in Mesenchymal Stem Cell-Based Therapy for Liver Ischemia/Reperfusion Injury in Rats

OBJECTIVE: To evaluate the impact of mesenchymal stem cells (MSCs) against hepatic I/R injury and explore the role of N-acetyltransferase 8 (NAT8) in the process. METHODS: We investigated the potential of injected MSCs systemically via the tail vein in healing injuried liver of the SD rat model of 70% hepatic I/R injury by measuring the biochemical and pathologic alterations. Subsequently, we evaluated the expression levels of NAT8 by western blotting in vivo. Concurrently, hydrogen peroxide (H(2)O(2))-induced apoptosis in the human normal liver cell line L02 was performed in vitro to evaluate the protective effects of MSC conditioned medium (MSC-CM) on L02 cells. In addition, we downregulated and upregulated NAT8 expression in L02 cells and induced apoptosis by using H(2)O(2) to study the protective role of NAT8. RESULTS: MSCs implantation led to a significant reduced liver enzyme levels, an advanced protection in the histopathological findings of the acutely injured liver and a significantly lower percentage of TUNEL-positive cells, which were increased after I/R injury. In vitro assays, MSC-CM inhibited hepatocyte apoptosis induced by H(2)O(2.) Moreover, overexpression or downregulation of NAT8 prevented or aggravated hepatocyte apoptosis induced by H(2)O(2), respectively. CONCLUSIONS: MSC transplantation provides support to the I/R-injured liver by inhibiting hepatocellular apoptosis and stimulating NAT8 regeneration.