Experimental listeriosis in rabbits: Biochemical changes in serum and cerebrospinal fluid

Abstract

This study was focused on serum and cerebrospinal fluid (CSF) biochemical changes in experimental Listeria monocytogenes infection in rabbits. Total of 20 New Zealand White rabbits were used. 14 New Zealand White rabbits were inoculated with Listeria monocytogenes 1/2a (L.m. 1/2a) by intracerebral way and 6 rabbits served as controls. Ten hours after the inoculation of the bacteria the rabbits developed symptoms of meningitis, with stiffness of the neck and fever. The existence and the severity of the inflammatory reaction were controlled by microscopic observation. The presence of bacteria into the cytoplasm of neutrophils and macrophages localised in inflammatory areas was confirmed by immunohistochemical analysis using rabbit polyclonal antibodies. We have analysed in serum and cerebrospinal fluid (CSF) the concentrations of glucose, total protein, and the enzymatic activities of aspartate aminotransferase (ASAT), alanine aminotransferase (ALAT) and lactate dehydrogenase (LDH). After intracerebral inoculation of bacteria the glucose concentrations in the serum and CSF decreased to 428.69 +/- 5.50 mg/l and 309.56 +/- 3.93 mg/l (mean +/- SE) respectively compared to control values of 975.33 +/- 84.34 mg/l and 689.22 +/- 65.13 mg/l (p less than or equal to 0.001). Total protein contents, the activities ofASAT, ALAT and LDH in the serum of infected animals increased to 98.92 +/- 1.97 g/l, 327.87 +/- 22.18 U/l, 292.39 +/- 4.66 U/l, 153.28 +/- 3.04 U/l respectively compared to 64.42 +/- 1.14 g/l, 67.91 +/- 7.79 U/l, 74.25 +/- 1.79 U/l, 49.35 +/- 1.20 U/l in control rabbits. In CSF, increases in total protein concentrations and in enzyme activities were also evidenced in inoculated rabbits. Moreover, serum and CSF LDH activities were correlated with brain injury (p < 0.05).