An experimental Staphylococcus aureus meningitis model for investigating induced leptomeningeal and subpial inflammation in rats: a transmission electron microscopy study.

OBJECTIVE To evaluate leptomeningeal and subpial inflammatory responses of experimental Staphylococcus aureus bacteriemia following intraperitoneal and intravenous applications and to compare the inflammatory reactions in different regions of central nervous system. MATERIAL AND METHODS Forty anesthetized rats were divided into four groups equal in number. The rats in group-I were given 1 ml suspension of Staphylococcus aureus intraperitoneally. Group-II was the control group of group I; it was administrated 1 ml 0.9% NaCl in water intraperitoneally. The rats in group-III were given the same amount of bacteria intravenously. Group IV was the control group of the group-III; it was administrated 1 ml 0.9% NaCl solution intravenously. The rats were sacrificed on the 21st day. Inflammatory changes of different regions of the central nervous system were examined under transmission electron microscopy. Statistical analysis was done by using variance analysis, Bonferroni, Tamhane post hoc, Student's t and univariate tests. RESULTS Thoracic and occipital regions were the most vulnerable zones. Increasing of collagen tissue was the most detected inflammatory change. CONCLUSION This experimental model can be used for inducing subpial and leptomeningeal inflammations and it may be developed for investigations of pathogenesis of leptomeningitis during systemic infections.

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