Atorvastatin Protects Against the Macrophage/Microglia-Related Neuroinflammation via Inhibiting Lipocalin-2 in Mouse Experimental Intracerebral Hemorrhage Model

There are few effective pharmacological interventions for intracerebral hemorrhage (ICH). Atorvastatin (Ato) has been shown to exert a substantial protective effect on ischemic stroke and is effective in alleviating neuroinflammation. Lipocalin-2 (LCN2), an important inflammation-regulating protein, has been demonstrated to play pivotal roles in post-ICH neuroinflammation. However, the exact role of Ato and whether LCN2 is involved after ICH remain largely unknown. In the current study, the BV2 (microglia) cell line, which was transfected with or without LCN2 for overexpression/interference, was co-cultured with primary cultured neurons and received blood infusion from C57BL/6 mice in vitro. For the in vivo study, atorvastatin was injected peritoneally into an ICH mouse model, and LCN2 specific knockout using the flox/cre system was performed in mice for mechanism study. Behavioral tests were conducted before ICH and on days 1, 3, and 7 post-ICH, and the brains and cultured cells were collected for protein, histological, and morphological studies. Our results showed that atorvastatin treatment alleviates neural damage and promotes neurological outcomes after ICH. Moreover, M1 activation and pro-inflammatory polarization are inhibited by atorvastatin. In both in vivo and in vitro models, the upregulation of LCN2 after ICH is substantially inhibited by atorvastatin. Studies on LCN2 transgenic mice and LCN2 overexpression/interference cells demonstrated that the suppression of macrophage/microglia (M/M) LCN2 participates in atorvastatin-mediated anti-neuroinflammation and neural protection effects. Therefore, our study suggests that atorvastatin treatment attenuates M/M-related neuroinflammation and protects neural recovery by down-regulating LCN2 after ICH. This study identified a potential novel therapeutic target for ICH treatment.