Cytoprotective Effects of Lipid Emulsion Against Bupivacaine-Induced Cytotoxicity in Human Rotator Cuff Fibroblasts

This study evaluated the protective effects of lipid emulsion (LE) against bupivacaine-induced cytotoxicity in human rotator cuff fibroblasts (hRCFs). hRCFs were divided into control, bupivacaine alone (Bupivacaine), LE alone (LE), LE-pretreated bupivacaine (LE + Bupivacaine), N-acetylcysteine alone (NAC), and NAC-pretreated bupivacaine (NAC + Bupivacaine). Cell viability was assessed by MTT and Live/Dead assays; ROS production by DCF-DA; apoptosis by Annexin V/PI staining and TUNEL assay; cleaved caspase-3 and PARP expression by Western blot; cell cycle by FACS; cell proliferation by Ki-67 staining; and wound healing. Cell viability decreased in a bupivacaine concentration-dependent manner (p < 0.001). Pretreatment with LE or NAC improved cell viability compared with bupivacaine alone (p < 0.001). ROS levels were elevated by bupivacaine, whereas LE and NAC pretreatments significantly reduced ROS (p < 0.001). Bupivacaine-induced apoptosis was significantly attenuated by LE and NAC, as evidenced by reductions in apoptosis rate, expression levels of cleaved caspase-3 and PARP-1, TUNEL-positive nuclei, and the subG1 population (p < 0.05). Cell proliferation and wound healing were suppressed by bupivacaine but restored by LE and NAC pretreatment. This study demonstrates bupivacaine-induced cytotoxicity in hRCFs and suggests that LE and NAC mitigate these effects by reducing oxidative stress and promoting cell survival and wound healing.