| Background:Bacterial meningitis is a common disease in Neurology in which streptococcus pneumoniae is one of the most common pathogenic bacteria. Levofloxacin is commonly used clinically to treat bacterial meningitis, but recent studies show that levofloxacin-resistant streptococcus pneumoniae increased year by year, which limits its wide application[1,2]. The guidance of diagnosis and treatment of community-acquired pneumonia in 2007 pointed out that application of levofloxacin treatment of pneumococcal pneumonia, should keep blood drug concentration as long as possible on the drug-resistant mutant prevention concentration (MPC), in order to ensure the success of the treatment and reduce the emergence of drug-resistant mutant. Studies have confirmed that on the blood-CSF barrier exists a variety of drug efflux transporter, including adenosine triphosphate combined box (ABC) superfamily member such as P-glycoprotein, multidrug resistance associated protein (MRP) and breast cancer resistance protein (BCRP), etc. BCRP play a role of efflux in physiological conditions, and efflux the drug outside the blood-CSF barrier. Previous experiments confirmed that the fluoroquinolone drugs such as ciprofloxacin and norfloxacin is substrate of the BCRP transporters, which may be barriers levofloxacin through the blood-CSF barrier. This study intends to establish model of bacterial meningitis and to observe the physiological and pathological situations of levofloxacin blood-CSF barrier transmittance with or without BCRP inhibitors, explores the value of BCRP inhibitors, and provides a new direction for clinical treatment of bacterial meningitis.Objective:1. To establish SD (Sprague-Dawley) rat model of Streptococcus pneumoniae (S. pneumoniae) meningitis;2. To study levofloxacin permeability on blood-CSF barrier with or without BCRP in the physiological state;3. To study levofloxacin permeability on blood-CSF barrier with or without BCRP in the pathological state;4. To compare the blood-CSF barrier permeability in physiological and pathological state, and application of BCRP receptor inhibitor in physiological and pathological conditions.Method:1. A total of 18 healthy male adult SD rats were randomly divided into blank control group, low-dose group, and high-dose group, which were given 75 ul saline injection, 1.5 x 107 cfu/ml pneumococcal bacteria suspension,1.5 × 108 cfu/ml pneumococcal bacteria suspension accordingly in the cerebellum medulla oblongata pool and get the brain tissue for HE stain after infected in 24 hours.2.52 male SD rats were randomly divided into blank control group (2), Levo group (25) and Levo+Panto group (25). Levo group was given a single tail intravenous levofloxacin (42 mg/kg), Levo+Panto group was given pantoprazole injection (40 mg/kg) via the tail vein 5 min before given levofloxacin. Each group was drawn serum and cerebrospinal fluid at the same time at point of 5 min,10 min,20 min,40 min,60 min respectively after given levofloxacin. Each time point repeat five rats. After pretreatment, various specimens were tested by high performance liquid chromatograph to determine the concentration of levofloxacin, with pharmacokinetic software WinNonlin program dealing with drug data and calculating the pharmacokinetic parameters.3. Rat model of bacterial meningitis was made according to the method 1. All fifty-two successfully established bacterial meningitis models were randomly divided as blank control group (2), Path+Levo group (25), Path+Levo+Panto group (25). Path+Levo group was given intravenous levofloxacin (42 mg/kg) via the tail vein, but Path+Levo +Panto group was given pantoprazole injection (40 mg/kg) via the tail vein in advance.Results:1. In the process of building models, success rate of low-dose group (1.5×107 cfu/ml) is 83.3% and that of high-dose group (1.5×108 cfu/ml) is 33.3%. Fifty-two S. pneumoniae meningitis rats models were made later in low doses.2. In physiological state, levofloxacin plasma concentrations in Levo group are highest at 10 min after tail intravenous injection, and at 20 min in the cerebrospinal fluid and decreased with time. The same thing was true about Levo+Panto group. To compare highest concentrations of Levo group and Levo+Panto group, difference was not statistically significant (t=0.322, p=0.756) and AUCplasma was the same. The difference of peak concentration and AUCCSF in CSF between two groups is statistically significant (t=2.640, p=0.015). The blood-CSF barrier permeability of Levo+Panto group is higher than the one of Levo group and difference between two groups is statistically significant (t=2.801, p=0.024).3. In pathological state, levofloxacin plasma concentrations in Path+Levo group are highest at 10 min after tail intravenous injection, and at 20 min in the cerebrospinal fluid and decreased with time. The same thing was true about Path+Levo+Panto group. To compare highest concentrations of Path+Levo group and Path+Levo+Panto group, difference was not statistically significant (t=0.542, p=0.403) and AUCplasma was the same(t=0.403, p=0.315). The difference of peak concentration and AUCCSF in CSF between two groups is statistically significant (t=3.551, P=0.007). The blood-CSF barrier permeability of Path+Levo group is 0.638±0.07 within 60 min and that of Path +Levo+Panto group is 0.786±0.059 with statistical difference (t= 4.728, p= 0.001).4. Compared with Levo group(0.303±0.03), the blood-CSF barrier permeability of Path+Levo group in pathological state increased significantly (0.638±0.07) with statistical significance. Compared with Levo+Panto group (0.378±0.01), the blood-CSF barrier permeability of Path+Levo+Panto group in pathological state increased significantly (0.786±0.059) with statistical significance.Conclusion:1. Bacterial meningitis rat model was established successfully and CSF can be successfully obtained through foramen magnum puncture with advantage of simple, less tissue injury and high success rate.2. Permeability of Panto+Levo group on blood-CSF barrier with BCRP inhibitor in the physiological state is higher than Levo group.3. Permeability of Panto+Levo group on blood-CSF barrier with BCRP inhibitor in the pathological state is higher than Levo group.4. The blood-CSF barrier permeability in pathological state increased significantly and get significance with BCRP inhibitor. |
PDF Full Text Request