Benign paroxysmal positional vertigo (BPPV) is the most common kind of vertigo,which can be divided into idiopathic and secondary types.Head trauma,surgery,and inner ear diseases may induce the secondary BPPV,but the etiology and pathogenesis of idiopathic BPPV is still unknown.Recent studies indicate that multiple factors are associated with idiopathic BPPV;in this article we will review the risk factors of idiopathic BPPV.

Objective To establish the mouse models of focal cerebral ischemic/reperfusion (I/R) injury combined with diabetes mellitus (DM),and investigate the possible mechanism of brain injury.Methods Eighty healthy C57BL/6J mouse were randomly divided into normal group and DM group;normal saline or streptozotocin was given to the mice in the two groups via intraperitoneal injection,and the concentration of glucose in peripheral blood was measured at different time points (2,4,6 and 8 weeks after injection);and then,the mice in the two groups were subdivided into normal sham-operated group,normal I/R group,DM sham-operated group and DM+I/R group (n=20).The focal I/R models were induced by thread occlusion method;the neuroethology assessment was determined by Zea Longa method in the normal I/R group and DM+I/R group;the morphology of the brain tissues in the four groups was observed by HE staining;changes of mRNA expressions of interleukin (IL)-1β,IL-6 and tumor necrosis factor (TNF)-α were analyzed by quantitative real-time PCR.Results (1)The glucose concentration in DM group was stable at a high level within the 8 weeks;as compared with normal group,DM group had significantly higher glucose concentration at each time point (P＜0.05).(2) The assessment scores of DM+I/R group (2.800±0.092) were significantly higher than those of I/R group (1.750±0.123,P＜0.05).(3) Typical pathological changes were presented by HE staining,DM+I/R group presented worse damage to the brain as compared with normal I/R group.(4) Quantitative real-time PCR showed that the IL-1β and TNF-α mRNA expressions in the normal I/R group was significantly higher than those in the normal sham-operated group (P＜0.05);the mRNA expressions of IL-1β,IL-6 and TNF-α in DM+I/R group were significantly increased as compared with those in the DM sham-operated and normal I/R group (P＜0.05).Conclusion The simple and reliable focal cerebral I/R combined with DM models are successfully established;inflammation reaction mediated by inflammatory factors might play an important role in this aggravating damage.

Objective To investigate whether cerebral ischemia reperfusion (I/R) injury combined with diabetes mellitus (DM) could elevate concentrations of serum high mobility group box 1 (HMGB 1) and its related inflammatory factors,and to explore the underlying mechanism of cerebral I/R injury combined with DM by blocking HMGB 1.Methods One hundred and forty healthy male C57BL/6 mice were randomly divided into four groups:normoglycemia (NG) group (n=25),NG+I/R group (n=25),hyperglycemia (HG) group (n=25),and HG+I/R group (n=65);40 mice in the HG+I/R group were chosen and divided into anti-HMGB1 group and IgG control group (n=20).High-fat feeding and i.p.injection of streptozotocin were used to establish HG mouse models,and then,middle cerebral artery occlusion was performed to establish the HG+I/R mouse models.Mice were treated with tail intravenous injection of 30 μg/g anti-HMGB 1 polyclonal antibody or control IgG 1 h before ischemia as previously described.After accomplishment of animal models,serum HMGB1 concentrations were evaluated by ELISA,the permeability of blood brain barrier (BBB) was observed by Evans-blue fluorescence quantitative method,quantitative real-time PCR was introduced to detect the mRNA expressions of interleukin (IL)-1β,IL-6,and inducible nitric oxide synthase (iNOS).Morphology changes of damaged brains were observed by HE staining.Results The serum HMGB 1 level in the HG+I/R group was significantly higher than that in the NG+I/R group (P＜0.05).HG+I/R group had significantly higher BBB permeability than NG+I/R group (P＜0.05),while anti-HMGB1 group had significantly lower BBB permeability than HG+I/R group (P＜0.05).As compared with the NG group,the HG+I/R group had unclear cellular structures in the brain tissues with necrosis neurocytes and interstitial edema,while the cellular structures were obviously improved in the anti-HMGB1 group.Expressions ofIL-1β,IL-6 and iNOS in the HG+I/R group were significantly elevated as compared with those in the NG+I/R group (P＜0.05),while those in the anti-HMGBl group had significantly decreased levels ofIL-1β and iNOS as compared with those in the HG+I/R group (P＜0.05),and the IL-6 level showed no significant difference between the two groups (P＜0.05).Conclusion The pathogenesis of DM could increase concentration of serum HMGB 1,and anti-HMGB 1 mAb could alleviate brain injury by blocking HMGB 1,and render a new promising therapeutic way for DM patients suffered with ischemic stroke.