Environmental enrichment restores cognitive deficits induced by experimental childhood meningitis

Abstract

Objective: To evaluate the influence of environmental enrichment (EE) on memory, cytokines, and brain-derived neurotrophic factor (BDNF) in the brain of adult rats subjected to experimental pneumococcal meningitis during infancy. Methods: On postnatal day 11, the animals received either artificial cerebrospinal fluid (CSF) or Streptococcus pneumoniae suspension intracisternally at 1 6 10 6 CFU/mL and remained with their mothers until age 21 days. Animals were divided into the following groups: control, control + EE, meningitis, and meningitis + EE. EE began at 21 days and continued until 60 days of age (adulthood). EE consisted of a large cage with three floors, ramps, running wheels, and objects of different shapes and textures. At 60 days, animals were randomized and subjected to habituation to the open-field task and the step-down inhibitory avoidance task. After the tasks, the hippocampus and CSF were isolated for analysis. Results: The meningitis group showed no difference in performance between training and test sessions of the open-field task, suggesting habituation memory impairment; in the meningitis + EE group, performance was significantly different, showing preservation of habituation memory. In the step-down inhibitory avoidance task, there were no differences in behavior between training and test sessions in the meningitis group, showing aversive memory impairment; conversely, differences were observed in the meningitis + EE group, demonstrating aversive memory preservation. In the two meningitis groups, IL-4, IL-10, and BDNF levels were increased in the hippocampus, and BDNF levels in the CSF. Conclusions: The data presented suggest that EE, a non-invasive therapy, enables recovery from memory deficits caused by neonatal meningitis.

The inflammatory response and neuronal injury in Streptococcus suis meningitis

“…Likewise, neurogenesis was significantly increased in rabbits 24 h after intracisternal infection with pneumococci [ 47 ] and in rats 7 days post infection [ 62 ]. In contrast to the mouse, rat and rabbit models [ 7 , 47 , 62 – 64 ], piglets were infected by intranasal inoculation which reflects the natural route of infection and were not treated with antibiotics.…”

Bacterial meningitis: an update of new treatment options

“…In an adult rat model of Str. pneumoniae meningitis, enriched environment improved aversive memory [211].…”

Bacterial meningitis in Africa

“…Although E. coli meningitis can be effectively treated with antibiotics, bacterial meningitis is especially severe in newborns and premature infants. However, the increased death rate happens in low- and middle-income nations where invasive infections are common; several patients do not have access to antibiotics ( 129 ), and the incidence of antibiotic resistance makes effective therapy a challenge ( 130 ). In neonates, 21 days of antibiotic is recommended for Gram (-) bacilli meningitis.…”