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Rhizopus arrhizus infection in mice causes brain histopathological alterations and exacerbates neuronal apoptosis
Rui Zheng1, Zishi Liu1, Li Wang1
1Key Laboratory of Animal Science of National Ethnic Affairs Commission of China, Key Laboratory of Qinghai-Tibetan Plateau Animal Genetic Resource Reservation and Utilization of Ministry of Education, Southwest Minzu University, Chengdu 610041, China.
Abstract:
Rhizopus arrhizus is a fungus that can cause central nervous system infections in animals, resulting in high morbidity and mortality, but the mechanism of injury is rarely reported. In this study, we investigated the mechanism of Rhizopus arrhizus damage to the central nervous system of mice by observing the clinical neurological symptoms and resolving the pathological changes in the ultrastructure of brain tissues, combined with the alteration of apoptosis-related genes and immunohistochemistry (IHC). The results showed that all the mice in the treated group died, the brain pyknosis of neurons, there were black mycelium aggregates around the blood vessels, and apoptotic vesicles were produced. The RT-qPCR results showed that, compared with the control group, the relative transcriptome levels of Caspase 8 and BcL-2 genes were significantly increased (P < 0.05), the relative transcriptome level of Caspase 9 gene was highly significant (P < 0.01), the relative transcriptome level of Caspase 3 and Bax gene was significantly decreased (P < 0.05), and the ratio of Bcl-2/Bax was significantly increased (P < 0.05) in the brains of the treated group. TUNEL staining showed that the rate of neuronal apoptosis in the treated group of mice was extremely significantly higher than that in the control group (P < 0.01). This study shows that Rhizopus arrhizus strain XMLO1 causes brain damage by triggering neuronal apoptosis. This study provided a theoretical basis for revealing the mechanism of Rhizopus arrhizus infection.
Insights
Rhizopus arrhizus fungus causes central nervous system infections in mice, leading to neuronal apoptosis and brain damage. This study reveals the mechanism behind this fungal-induced brain injury.
Area of Science:
- Mycology
- Neuroscience
- Pathology
Background:
- Rhizopus arrhizus infections can cause severe central nervous system (CNS) disease in animals.
- The precise mechanisms underlying R. arrhizus-induced CNS damage remain largely unelucidated.
- Understanding these mechanisms is crucial for developing effective treatments.
Purpose of the Study:
- To investigate the pathological mechanisms of Rhizopus arrhizus-induced central nervous system damage in a mouse model.
- To elucidate the role of neuronal apoptosis in R. arrhizus brain infections.
Main Methods:
- Mice were infected with Rhizopus arrhizus strain XMLO1.
- Neurological symptoms, brain ultrastructure, apoptosis-related gene expression (RT-qPCR), and immunohistochemistry (IHC) were analyzed.
- TUNEL staining was used to assess neuronal apoptosis rates.
Main Results:
- Infection led to 100% mortality in the treated group, characterized by neuronal pyknosis and mycelial aggregates.
- Significant alterations in apoptosis-related gene expression were observed, including increased Caspase 8, Caspase 9, and Bcl-2, with decreased Caspase 3 and Bax.
- TUNEL staining confirmed a significantly higher rate of neuronal apoptosis in infected mice compared to controls.
Conclusions:
- Rhizopus arrhizus strain XMLO1 induces brain damage in mice primarily by triggering neuronal apoptosis.
- The study provides a theoretical framework for understanding the pathogenesis of R. arrhizus CNS infections.
