The Effects Of 3% NaCl On Visceral Organ In The Bacterial Meningitis Model Induced By E.coli In Rabbits

Background Bacterial meningitis is still one of the most common, severe central neurological infectious disease in children. Despite significant advances in diagnostic techniques, antimicrobial chemotherapy, and adjuvant use of anti-inflammatory agents, mortality and morbidity of neurological sequelae of bacterial meningitis remains high. Bacterial meningitis always complicated with cerebral edema, recent studies have demonstrated that antibiotics deteriorate inflammation, cerebral edema and intracranial hypertension in a short-term because their dissolving effects on bacilli. The prognosis of bacterial meningitis is closely related to the severities of cerebral edema. The general principle of fluid therapy for brain edema requires dehydrating and limiting the fluid intake to reduce the brain edema, especially limited the intake of fluid containing sodium. But over the past decade many clinical and experimental researches show that restricting the fluid intake can not improve the prognosis. Hence, our hospital proposed a new fluid therapy, based on the patient's condition, called fluid replenishment together with dehydration. And now it's demonstrated this new therapy is more effective。20% mannitol is the most widespread dehydrator at present, but it may cause some serious side effects:the cerebrospinal fluid pressure bounce, impaired renal function and so on. Therefore, seeks for the effective and low side effect auxiliary treatment to bacterial meningitis has been widely researched. It has demonstrated that 3% hypertonic saline can lower intracranial pressure, improve cerebral perfusion pressure, alleviate cerebral edema and neuronal injury, ameliorate regional cerebral microcirculation and metabolism etc. In order to observe weather 3% NaCl makes side effects to visceral organ when it used as an adjunctive agents on bacterial meningitis, we design this experiment.Objective To explore the effects of 3% NaCl on visceral organ when it used as an adjunctive agents on BM induced by E.coli in rabbits.Methods Rabbits were randomly divided into 5 groups:control group, model group, Ampicillin group,3% NaCl group (H group),20% mannitol group (M group). Rabbits were inoculated intracisternally saline or 4×107CFU/ml of E.coli, then treated with different disposal. The levels of IL-1,IL-10,TNF-awere detected by enzyme-linked immuno assay both in serum and in bronchoalveolar lavage fluid (BALF); the water and Evan's blue (EB) content of brain, lung, heart, liver, spleen, kidney, pancreas were measured respectly; the leukocyte count and protein content of bronchoalveolar lavage fluid (BALF) were determined. The lung histology was also assessed.Results 1. The water content of organs:The water content of brain in the model and Ampicillin group was significantly higher than that of control group(p<0.01), and it was significantly decreased after treatment with 3% NaCl or 20% mannitol (p<0.01 or p<0.05). The water content of brain in H group was lower than other groups (p<0.01). And the water content of the visceral organs (lung, heart, liver, spleen, kidney, pancreas) was not changed.2. The EB content of organs:The EB content of brain in the model group was significantly higher than that of control group (p<0.01), and that of Ampicillin group was highest (p<0.01). and it was significantly decreased after treatment with 3%NaCl or 20% mannitol (p<0.01 or p<0.05). The EB content of visceral organ (lung, heart, liver, spleen, kidney, pancreas) wasn't significantly different among groups.3. The wet to dry ratio of lung:The ratio was not different among groups. 4. The leukocytes count and protein content of BALF:The number of leukocytes of BALF in the infected groups was significantly higher than the control group, particularly in Ampicillin group (p<0.01). It was significantly decreased after treatment with 3% NaCl or 20% mannitol (p<0.01), especially in H group, which was the least (p<0.01). And the number of leukocytes of M group was less than that of infected groups (p<0.01), but more than that of control group. The protein content of BALF was not significantly different among groups.5. The IL-1, IL-10, TNF-alevel of BALF:The levels of TNF-aand IL-1 in infected groups were significantly higher compared with control group (p<0.01), and the level of TNF-ain the Ampicillin group was highest among groups (p<0.05). The levels of TNF-aand IL-1 were decreased by treatment with 3%NaCl or 20%mannitol (p<0.01 or p<0.05), especially in H group. The level of IL-10 was not different among groups.6. The IL-1, IL-10, TNF-alevel of serum:The levels of TNF-aand IL-1 in the infected groups were significantly higher than control group (p<0.01), especially in the Ampicillin group, that were the higtest (p<0.01); and both decreased after treatment by 3% NaCl or 20% mannitol (p<0.01), especially in H group, but M group was still higher than control group(p<0.05). The level of IL-10 in H group was higher than that of control group (p<0.05), and the level of IL-10 in M group was significantly higher than control group and the infected group (p<0.05).7. Histopathological study:In model group and the Ampicillin group, we can see some of the alveolar septum widend or fractured congestion in part of the pulmonary interstitial, local atelectasis and emphysema. Also we can see alveolar macrophages in some of the alveolar cavity. After treatment with 3% NaCl or 20% mannitol, there were not significantly changes. And, the alveolar macrophage counts were not significantly different among groups.Conlusion 3% NaCl can alleviate cerebral edema, but do not lead to visceral organ dehydration. The bacterial meningitis induced by E.coli causes the low-grade increase of systemic pro-inflammatory cytokines, and 3% NaCl can ameliotate this state.