Efficacy of hyaluronic acid, absorbable collagen sponge, and their combination in minimizing bisphosphonate-related osteonecrosis of the jaws (BRONJ) after dental extraction: a preliminary animal histomorphometric study / 대한악안면성형재건외과학회지

Methods@#For simulating BRONJ, zoledronic acid was administered to 40 rats for 5 weeks. Two weeks later, a right first molar was extracted from each rat. The rats were randomized into four groups of socket treatments: control (empty extraction socket) or with sockets filled with ACS, HA, or HA+ACS (n=4×10). After 2 weeks, 5 rats in each group were sacrificed and subjected to histopathologic and histomorphometric evaluation. Eight weeks post-surgically, the rest of rats were euthanized and histologically examined. The Kruskal-Wallis test was used to compare the four treatments at each time point (α=0.05). @*Results@#Six rats were lost overall. In the second week, vascularization was higher in ACS group (P0.05); empty lacunae were the most and fewest in control and HA+ACS groups, respectively (P0.05). In the eighth week, vascularization was not different in groups (P>0.05); the highest and lowest osteoclast activities were seen in the control and HA+ACS groups, respectively (P<0.05); empty lacunae were the most and fewest in control and HA+ACS, respectively (P<0.05); maximum and minimum numbers of eosinophils were in control and HA+ACS groups, respectively (P<0.05); HA and control groups exhibited the highest and lowest lymphocyte counts, respectively (P<0.05); the lowest and highest neutrophil counts were observed in HA+ACs and control groups, respectively (P<0.05); and the highest and lowest extents of the live bone were observed in HA+ACS and control groups, respectively (P<0.05). @*Conclusions@#Within the limitations of this preliminary animal study, HA and especially HA+ACS seem a proper method for preventing or treating BRONJ.

Effect of Gallic acid on dementia type of Alzheimer disease in rats: electrophysiological and histological studies

Introduction: To study the effect of gallic acid [GA] on hippocampal long-term potentiation [LTP] and histological changes in animal model of Alzheimer disease [AD] induced by beta-amyloid [Abeta]

Methods: Sixty-four adult male Wistar rats [300 +/- 20 g] were divided into 8 groups: 1] Control [Cont]; 2] AD; 3] Sham; 4-7] AD+GA [50, 100, and 200 mg/kg for 10 days, orally] or vehicle, 8] Cont+GA100, Abeta [1microg/microL in each site] was infused into hippocampus bilaterally. Changes of amplitude and slope of LTP induced in hippocampal dentate gyrus [DG] were evaluated by high frequency stimulation [HFS] of perforant path [PP]

Results: Data showed that LTP amplitude and area under curve significantly impaired in AD rats [P<0.001], while significantly improved in AD rats treated with GA [P<0.05, P<0.01]

Conclusion: Current findings suggest that GA reduces neural damage and brain amyloid neuropathology and improves cognitive function via free radicals scavenging and inhibiting oligomerization of Abeta but with no effect on healthy rats

Neuropathological changes in brain cortex and hippocampus in a rat model of Alzheimer's disease

Alzheimer's disease [AD] is a neurodegenerative disorder with progressive loss of cognitive abilities and memory loss. The aim of this study was to compare neuropathological changes in hippocampus and brain cortex in a rat model of AD. Adult male Albino Wistar rats [weighing 250-300 g] were used for behavioral and histopathological studies. The rats were randomly assigned to three groups: control, sham and beta-amyloid [Abeta] injection. For behavioral analysis, Y-maze and shuttle box were used, respectively at 14 and 16 days post-lesion. For histological studies, Nissl, modified Bielschowsky and modified Congo red staining were performed. The lesion was induced by injection of 4 microL of Abeta [1-40] into the hippocampal fissure. In the present study, Abeta [1-40] injection into hippocampus could decrease the behavioral indexes and the number of CA1 neurons in hippocampus. Abeta injection CA1 caused Abeta deposition in the hippocampus and less than in cortex. We observed the loss of neurons in the hippocampus and cerebral cortex and certain subcortical regions. Y-maze test and single-trial passive avoidance test showed reduced memory retention in AD group. We found a significant decreased acquisition of passive avoidance and alternation behavior responses in AD group compared to control and sham group [P<0.0001]. Compacted amyloid cores were present in the cerebral cortex, hippocampus and white matter, whereas, scattered amyloid cores were seen in cortex and hippocampus of AD group. Also, reduced neuronal density was indicated in AD grouper ovariectomy