Mechanism of neuroprotective effect induced by QingKaiLing as an adjuvant drug in rabbits with E. coli bacterial meningitis.

OBJECTIVE: To explore the neuroprotective effects and underlying mechanism of QingKaiLing (QKL) as an adjuvant treatment for bacterial meningitis.
METHOD: E. coli bacterial meningitis rabbits were treated with antibiotics (ampicillin) alone or in combination with QKL. The number of leukocytes and the concentration of protein in the cerebrospinal fluid (CSF) of rabbits were determined at 0, 16, and 26 hours after treatment. Brain water, sodium, potassium, and calcium contents were determined at the 26-hour time point. The level of matrix metalloproteinase-9 in the brain was also determined by Western blot. RESULT: The average number of leukocytes and the concentration of protein in CSF of the QKL adjuvant treatment group were reduced compared with the ampicillin alone group. Brain water, sodium, and calcium contents were reduced in the QKL adjuvant treatment group. The level of MMP-9 in brain tissue was also reduced in the QKL adjuvant treatment group.
CONCLUSION: QKL adjuvant treatment alleviates the aggravated inflammatory reaction and partially protects brain tissue from antibiotic-induced injury. The mechanism of this neuroprotective effect of QKL may be due to decreased levels of Ca2+ and MMP-9 in the brain.