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Aberrations in cerebral vascular functions due to Plasmodium yoelii nigeriensis infection in mice
M C Sharma1, L M Tripathi, M Rastogi
1Division of Biochemistry, Central Drug Research Institute, Lucknow, India.
Abstract:
Plasmodium yoelii nigeriensis infection in mice caused an increase in uptake of 125I-labeled bovine serum albumin, 51Cr-labeled erythrocytes and Evans blue dye from peripheral circulation into the brain. Isolated cerebral microvessels which were characterized in terms of their morphology under scanning electron microscope and enhancement of the specific activities of biochemical markers, viz. alkaline phosphatase, gamma-glutamyl transpeptidase, and monoamine oxidase, showed significant decrease in these activities due to P. yoelii nigeriensis infection. On the other hand, relatively minor (statistically insignificant) changes occurred in the first two enzyme specific activities in the cerebral cortex and monoamine oxidase registered an increase in this tissue due to infection. Histological examination of the cerebral tissue of infected animals by light and electron microscopy showed broken blood vessel walls and leakage of erythrocytes into extravascular space, some of which contained intraerythrocytic malarial parasite in a state of cell division.
Insights
Malaria infection in mice disrupts the blood-brain barrier, increasing brain uptake of substances and damaging cerebral microvessels. This study reveals significant changes in brain enzyme activity and structure due to Plasmodium yoelii nigeriensis.
Area of Science:
- Neuroscience
- Infectious Diseases
- Pathology
Background:
- Plasmodium yoelii nigeriensis is a parasite that causes malaria.
- Malaria infection can affect various organs, including the brain.
Purpose of the Study:
- To investigate the effects of Plasmodium yoelii nigeriensis infection on the murine brain.
- To examine changes in blood-brain barrier permeability, cerebral microvessel enzyme activity, and brain histology.
Main Methods:
- Mice were infected with Plasmodium yoelii nigeriensis.
- Uptake of labeled albumin, erythrocytes, and dye into the brain was measured.
- Cerebral microvessels were isolated and enzyme activities (alkaline phosphatase, gamma-glutamyl transpeptidase, monoamine oxidase) were assessed.
- Brain tissue was examined using light and electron microscopy.
Main Results:
- Infection increased the uptake of albumin, erythrocytes, and dye into the brain.
- Specific activities of alkaline phosphatase, gamma-glutamyl transpeptidase, and monoamine oxidase in cerebral microvessels significantly decreased.
- Cerebral cortex enzyme activities showed minor changes, with monoamine oxidase increasing.
- Histology revealed broken blood vessel walls and erythrocyte leakage into the brain tissue.
Conclusions:
- Plasmodium yoelii nigeriensis infection compromises the blood-brain barrier in mice.
- Cerebral microvessels are significantly affected, showing reduced enzyme activity and structural damage.
- These findings highlight the neuropathological impact of malaria infection.