The effect of minocycline on novel object recognition memory and beta amyloid protein expression in alzheimer’s disease rat model
Alzheimer’s disease is a progressive neurodegenerative disorder which indicates gradual decline in cognitive impairment. It is the reason for mental and cognitive alteration such as low memory capacity, intellect and personality disorder and also behavioral changes in population older than the ag...
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| Format: | Monograph |
| Language: | English |
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Universiti Sains Malaysia
2016
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| Online Access: | http://eprints.usm.my/62609/ http://eprints.usm.my/62609/1/KUMARAROOBINI%20AP%20POOBALAN%20-%20e.pdf |
| Summary: | Alzheimer’s disease is a progressive neurodegenerative disorder which indicates gradual
decline in cognitive impairment. It is the reason for mental and cognitive alteration such as low
memory capacity, intellect and personality disorder and also behavioral changes in population
older than the age of 65 (Saeed Sadigh-Eteghad, 2014) (Crew and Masliah 2010). This research
study focuses mainly on the effect of minocycline on novel object recognition memory in
Lipopolysaccharide (LPS) induced rats. Besides that, it is also to determine the effects of LPS
administration on novel object recognition test and in Ap protein plaque deposition in rat brain.
Administration of lipopolysaccharide (LPS) triggers neuroinflammation along with memory
shortfall and leads to beta amyloid protein plaque deposition (Friihauf el al., 2015). Therefore,
LPS- induced Sprague Dawley rat models were used as AD paradigm for this study in order to
investigate the effect of minocycline on their memory impairment and beta amyloid protein
plaque deposition. However the contribution of minocycline (microglial activation inhibitor)
treatment in LPS- induced neuroinflammation AD model especially in in-vivo study is still
unclear and need further investigation (Biscaro el al., 2012). The Novel Object Recognition
(NOR) test is to evaluate the rat’s preference towards the novel object as to monitor its memory
impairment of rats of various groups (Normal Saline, LPS, LPS with minocycline (50mg/kg), LPS with memantine (2mg/kg) treatment). 1st group consists of normal rats and the rest were injected with LPS. Then, the 3rd and 4th group were treated with minocycline and memantine respectively for 7 days consecutively. Based on histological finding, there were no beta amyloid
deposition found in all of the rats. Hence, there is no data to analyze for investigating the
significance. As the minocycline able to inhibit microglial activation which renders the further cognitive impairment while improving it, the LPS induced rats under minocycline treatment are
anticipated to exhibit higher object recognition index than LPS induced rats. Besides that, LPS
induced rats were assumed to show lower recognition index compared to normal rats to prove the
memory impairment is due to LPS. The statistical analysis was done using One-Way Anova to
analyze the recognition index produced by the four groups. According to the result, LPS induced
rats under minocycline treatment shows the lowest value of recognition index among the other
groups. In fact, none of the comparisons between groups were significant. However, LPS
induced rats showed higher recognition index than normal rats as assumed. The minocycline
treatment failed to produce the expected effect on NOR test. As the conclusion, the dose of
minocycline was not optimum to recover the neuroinflammatory condition in rats. The dose optimization should have done to get the expected result. LPS successfully caused memory impairment even in the absence of beta amyloid protein. The drug, memantine treatment was successful in improving the rats’ memory. |
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