Relationship between tissue hydroxyl radical and oxidatively modified macromolecule levels

Comparative Study of Time-Dependent Aluminum Exposure and Post-Exposure Recovery Shows Better Improvement in Synaptic Changes and Neuronal Pathology in Rat Brain After Short-Term Exposure

Aluminum is a ubiquitous metal that causes multiple brain pathologies such as, cognitive dysfunction and Alzheimer's disease like symptoms. Exposure to aluminum through drinking water is responsible for hampering learning and memory. This study aimed to compare (1) the time-dependent effect of aluminum exposure (keeping total exposure of 5850 mg/kg same) in two durations, 30 and 45 days, and (2) to compare post-exposure self-recovery effect after 20 days in both (30 and 45 days exposure) groups. Rats were given 130 and 195 mg/kg of AlCl₃·6H₂O for 45 and 30 days respectively, to see the time-dependent exposure effect. At the end of exposure, rats were given distilled water and allowed to self-recover for 20 days to study the recovery. Expression levels of synaptic genes (Syp, SNAP25, Nrxn1/2, PSD95, Shank1/2, Homer1, CamkIV, Nrg1/2 and Kalrn) were measured using qPCR and compared in the exposure and recovery groups. Cellular morphology of the rat brain cortex and hippocampus was also investigated. Damage in lipid and protein profile was measured by employing FTIR. Results showed downregulation of mRNA expression of synaptic genes, plaques deposition, disorganization in lipid and protein profile by increasing membrane fluidity, and disorder and alteration of protein secondary structure after both exposure periods. However, better improvement/recovery in these parameters were observed in recovery group of 30 days aluminum exposure compared to 45 days aluminum exposure group. Taken together, these results suggested that short-term exposure resulted in better restoration of lipid and protein profile after time-dependent exposure of aluminum than prolonged exposure.

Role of Cytochrome P450 Enzyme in Plant Microorganisms' Communication: A Focus on Grapevine

Cytochromes P450 are ancient enzymes diffused in organisms belonging to all kingdoms of life, including viruses, with the largest number of P450 genes found in plants. The functional characterization of cytochromes P450 has been extensively investigated in mammals, where these enzymes are involved in the metabolism of drugs and in the detoxification of pollutants and toxic chemicals. The aim of this work is to present an overview of the often disregarded role of the cytochrome P450 enzymes in mediating the interaction between plants and microorganisms. Quite recently, several research groups have started to investigate the role of P450 enzymes in the interactions between plants and (micro)organisms, focusing on the holobiont Vitis vinifera. Grapevines live in close association with large numbers of microorganisms and interact with each other, regulating several vine physiological functions, from biotic and abiotic stress tolerance to fruit quality at harvest.

Biochemical Alterations in White Matter Tracts of the Aging Mouse Brain Revealed by FTIR Spectroscopy Imaging

White matter degeneration in the central nervous system (CNS) has been correlated with a decline in cognitive function during aging. Ultrastructural examination of the aging human brain shows a loss of myelin, yet little is known about molecular and biochemical changes that lead to myelin degeneration. In this study, we investigate myelination across the lifespan in C57BL/6 mice using electron microscopy and Fourier transform infrared (FTIR) spectroscopic imaging to better understand the relationship between structural and biochemical changes in CNS white matter tracts. A decrease in the number of myelinated axons was associated with altered lipid profiles in the corpus callosum of aged mice. FTIR spectroscopic imaging revealed alterations in functional groups associated with phospholipids, including the lipid acyl, lipid ester and phosphate vibrations. Biochemical changes in white matter were observed prior to structural changes and most predominant in the anterior regions of the corpus callosum. This was supported by biochemical analysis of fatty acid composition that demonstrated an overall trend towards increased monounsaturated fatty acids and decreased polyunsaturated fatty acids with age. To further explore the molecular mechanisms underlying these biochemical alterations, gene expression profiles of lipid metabolism and oxidative stress pathways were investigated. A decrease in the expression of several genes involved in glutathione metabolism suggests that oxidative damage to lipids may contribute to age-related white matter degeneration.

A Modified Murine Abdominal Aortic Aneurysm Rupture Model Using Elastase Perfusion and Angiotensin II Infusion

BACKGROUND

The perfused elastase AAA model and subcutaneous Angiotensin II infusion AAA model are widely used murine AAA models. We modified these two current models and developed a new murine model to study aneurysm formation and rupture.

METHODS

The murine abdominal aorta was treated with elastase. Angiotensin II was infused at a dose of 1,000 ng/kg/min via an osmotic pump placed subcutaneously. A saline osmotic pump was used as the control. The aortas were harvested from the mice 4 weeks later, or earlier if mice died. The abdominal aorta was inspected using ultrasound and microscopy for aneurysm formation and/or signs of rupture. The aneurysm outcome was measured using aortic expansion and proinflammatory cytokine expression. It was also compared with the established conventional elastase perfusion and angiotensin II infusion abdominal aortic aneurysm models.

RESULTS

By day 28 after surgery, all abdominal aortas of mice treated in the modified group had dilated and progressed to abdominal aortic aneurysms with 60% ruptured aneurysms, whereas none of the control aortas treated with saline became aneurysmal. In mice treated with elastase solution alone, 100% developed aneurysms and only one had a ruptured aneurysm. In mice given angiotensin II infusion alone, 37.5% developed aneurysms and none had a ruptured aneurysm. Histological examination of the modified murine abdominal aortic aneurysm rupture model was identical to that observed in the conventional elastase model. Quantitative polymerase chain reaction analysis revealed similarly increased levels of proinflammatory cytokines.

CONCLUSIONS

We modified two current murine abdominal aortic aneurysm models to develop a murine abdominal aortic aneurysm model with consistent aneurysm formation and high rupture incidence, which can be used for studying abdominal aortic aneurysm rupture and treatment.