OBJECTIVETo investigate the expression of neuroglobin (Ngb) in frontal cortex, cerebrospinal fluid (CSF) and serum in rats with brain injury induced by LPS and to elucidate its significance.

METHODSSeventy adult Sprague-Dawley rats were randomly divided into LPS (n = 60, with injection of 0.1 mg/kg LPS into cistern) and control (C, n = 10, with injection of equal volume of isotonic saline into cistern) groups, with 10 rats in each group. The plasma, CSF as well as frontal cortex from sacrificed rats were collected in LPS group at 3, 6, 12, 24, 48, 72 post injection hour (PIH), with 10 rats at each time point. The protein expression of Ngb was measured by enzyme-linked immunosorbent assay (ELISA) and Western blot. Expression of Ngb in frontal cortex was determined by SP. Water content of frontal cortex was assessed by drying method. The correlation among Ngb contents in serum, CSF, frontal cortex and water content of frontal cortex was analyzed with multiple comparison.

RESULTSNgb expression (by ELISA): Ngb expression of frontal cortex, CSF, and serum in LPS group was higher than that in C group at each time point, and it peaked at48 PBH (35.4 +/- 3.9, 22.7 +/- 3.1, 14.4 +/- 2.8 ng/mL, respectively, P < 0.01). Ngb expression (by Western blot): Ngb protein with relative molecular mass of 17 x 10(3) was observed in each group. Ngb expression detected by Western blot was similar to that detected by ELISA. Brain water content was significantly greater in LPS group than that of C group at 6-72 PIH (P < 0.01), and it peaked at 48 PBH (83.3 +/- 1.9)%. Ngb contents in serum, CSF, frontal cortex, and water content of frontal cortex were positively correlated with multiple comparison ( y = 0.631-0.719, P < 0.01).

CONCLUSIONSUp-regulation of Ngb expression in brain injury induced by LPS is correlated with duration after challenge of LPS.