The investigation of the molecular changes during lipopolysaccharide-induced systemic inflammation on rat hippocampus by using FTIR spectroscopy

The aim of this study is to reveal the molecular changes accompanying the neuronal hyper-excitability during lipopolysaccharide (LPS)-induced systemic inflammation on rat hippocampus using Fourier transform infrared (FTIR) spectroscopy. For this aim, the body temperature of Wistar albino rats administered LPS or saline was recorded by radiotelemetry. The animals were decapitated when their body temperature began to decrease by 0.5°C after LPS treatment and the hippocampi of them were examined by FTIR spectroscopy. The results indicated that systemic inflammation caused lipid peroxidation, an increase in the amounts of lipids, proteins and nucleic acids, a decrease in membrane order, an increase in membrane dynamics and changes in the secondary structure of proteins. Principal component analysis successfully separated control and LPS-treated groups. In conclusion, significant structural, compositional and functional alterations occur in the hippocampus during systemic inflammation and these changes may have specific characteristics which can lead to neuronal hyper-excitability.

Voltammetric and In Situ Spectroscopic Investigations on the Redox Processes of Trioxotriangulene Neutral Radicals on Graphite Electrodes

To investigate the microscopic electrochemical dynamics of a stable trioxotriangulene (TOT) organic neutral π-radical on a graphite electrode surface, voltammetric and in situ infrared (IR) spectroelectrochemical studies were conducted using electrolyte solutions containing TOT monoanions. Upright columnar crystals (face-on alignment) of the TOT neutral radical were preferentially formed and dissolved in a rather reversible manner in the electrolyte with a low concentration of TOT monoanion under electrochemical conditions; however, more flat-lying columnar crystals (edge-on alignment) were formed in a higher concentration electrolyte. The flat-lying crystals remained on the graphite surface even at a fully reduced potential, owing to the lack of direct π-π interactions between the molecules and the graphite electrode. In situ IR attenuated total reflectance spectroscopy analyses successfully characterized the alignment of the columnar crystals of the TOT neutral radicals and their electrochemical behaviors, including the possible origins of the irreversible redox reaction of TOT on the graphite electrode.

The recovery effect of Vitamin C on structural alterations due to Streptozotocin-Induced diabetes in rat testicular tissues

Type I Diabetes is a multisystem disease that causes alterations in carbohydrate, protein, and fat metabolisms due to hyperglycemia. It has an extensive pathology, especially the mechanism involving oxidative stress is still complex. Type I diabetes is correlated with increased formation of free radicals and decreased levels of antioxidant potential. Vitamin C (Vit C) is a powerful antioxidant that participates in antioxidant defense, protecting lipid membranes and proteins from oxidative damage by donating electrons to free radicals. The effect of type I diabetes and the recovery role of Vit C on the structure and composition of the biomolecular content of testicular tissue is still unknown. Therefore, the current study aimed to investigate the alterations in the biomolecules of rat testes due to Streptozotocin (STZ)-induced type I diabetes using Attenuated Total Reflectance (ATR)-Fourier Transform Infrared (FTIR) spectroscopy and histological staining. The results revealed that the biomolecular structure and composition of testicular tissue are highly affected due to the development of diabetes. We obtained decreased saturation levels and increased unsaturation index in the lipids indicating the presence of lipid peroxidation in the diabetic state. The elevated lipid peroxidation levels have been implicated in the pathogenesis of naturally occurring and chemically induced diabetes. On the other hand, the protein content of diabetic rat testicular tissue was shown to decrease considerably, indicating an increase in proteolysis processes. Supporting the ratio of protein structural and conformational change, protein secondary structural components were also found to alter substantially in the diabetic state. Diabetes was also shown to lead to a decrease in the content of nucleic acids compared to proteins. These diabetes-induced alterations were found to be substantially recovered with the administration of Vit C. Although different doses and administration types of Vit C have been reported in the literature, there is no consensus yet. Therefore, we used three different doses of Vit C in our study as high (100 mg/kg/day), medium (50 mg/kg/day) and low (15 mg/kg/day) doses intraperitoneally in the present study, and the medium dose was found to be the most effective in the recovery from the diabetes-induced structural damages on rat testicular tissue. Vit C may have a therapeutic effect to be used as a complementary therapy in the treatment of diabetes.

A Brief Review of FT-IR Spectroscopy Studies of Sphingolipids in Human Cells

In recent years, sphingolipids have attracted significant attention due to their pivotal role in cellular functions and physiological diseases. A valuable tool for investigating the characteristics of sphingolipids can be represented via FT-IR spectroscopy, generally recognized as a very powerful technique that provides detailed biochemical information on the examined sample with the unique properties of sensitivity and accuracy. In the present paper, some fundamental aspects of sphingolipid components of human cells are summarized, and the most relevant articles devoted to the FT-IR spectroscopic studies of sphingolipids are revised. A short description of different FT-IR experimental approaches adopted for investigating sphingolipids is also given, with details about the most commonly used data analysis procedures. The present overview of FT-IR investigations, although not exhaustive, attests to the relevant role this vibrational technique has played in giving significant insight into many aspects of this fascinating class of lipids.

Determination of the dose-dependent toxic effects of mad honey on mouse liver using ATR-FTIR spectroscopy

Mad honey (MH) is obtained from Rhododendron plants, which are extensively grown in some regions of the world such as Europe, North America, Tropical Asia and Turkey. Although it has been known that MH induces adverse effects in the body due to grayanotoxin (GTX) in it, it is widely used for some medical purposes by the public. In this study, the effects of MH (25, 50 and 75 mg/kg) and GTX-III (0.01 mg/kg), which is the pure form of the most toxic type of the GTXs in MH, were investigated on the mouse liver at molecular level via Attenuated Total Reflection-Fourier Transform Infrared (ATR-FTIR) spectroscopy. The results showed that 25 and 50 mg/kg of MH didn't cause any significant alterations in the liver tissue except a decrease in the glycogen amount. However, significant differences were observed between 75 mg/kg MH and GTX-III treated groups and control group. For example, the amounts of saturated lipids, nucleic acids and proteins increased in the 75 mg/kg MH and GTX-III treated groups. A decrease in the ratios of unsaturated/saturated lipid, CH₂/lipid and carbonyl/lipid and an increase in the ratio of CH₃/lipid were observed after the administration of 75 mg/kg MH and GTX-III, all of which may be a consequence of lipid peroxidation. Moreover, 75 mg/kg MH and GTX-III caused a decrease in the membrane order, an increase in the membrane fluidity and some important changes on the secondary structure of proteins indicating protein denaturation. In addition, Hierarchical Cluster Analysis (HCA) and Principal Component Analysis (PCA) confirmed these findings. These results revealed that MH induces significant dose-dependent toxic effects in the structure and function of the liver tissue. This study also showed that ATR-FTIR spectroscopy provides a rapid and sensitive monitoring of the changes induced by a toxic compound on biological tissues at molecular level.

Structural effects of simvastatin on liver rat [corrected] tissue: Fourier transform infrared and Raman microspectroscopic studies

Simvastatin is one of the most frequently prescribed statins because of its efficacy in the treatment of hypercholesterolemia, reducing cardiovascular risk and related mortality. Determination of its side effects on different tissues is mandatory to improve safe use of this drug. In the present study, the effects of simvastatin on molecular composition and structure of healthy rat livers were investigated by Fourier transform infrared and Raman imaging. Simvastatin-treated groups received 50 mg/kg/day simvastatin for 30 days. The ratio of the area and/or intensity of the bands assigned to lipids, proteins, and nucleic acids were calculated to get information about the drug-induced changes in tissues. Loss of unsaturation, accumulation of end products of lipid peroxidation, and alterations in lipid-to-protein ratio were observed in the treated group. Protein secondary structure studies revealed significant decrease in α-helix and increase in random coil, while native β-sheet decreases and aggregated β-sheet increases in treated group implying simvastatin-induced protein denaturation. Moreover, groups were successfully discriminated using principal component analysis. Consequently, high-dose simvastatin treatment induces hepatic lipid peroxidation and changes in molecular content and protein secondary structure, implying the risk of liver disorders in drug therapy.

Ionizing radiation induces structural and functional damage on the molecules of rat brain homogenate membranes: a Fourier transform infrared (FT-IR) spectroscopic study

Humans can be exposed to ionizing radiation, due to various reasons, whose structural effects on biological membranes are not well defined. The current study aims to understand the ionizing radiation-induced structural and functional alterations in biomolecules of brain membranes using Fourier transform infrared (FT-IR) spectroscopy using rat animal models. For this purpose, 1000 cGy of ionizing radiation was specifically directed to the head of Sprague Dawley rats. The rats were decapitated after 24 h. The results revealed that the lipid-to-protein ratio decreased and that irradiation caused lipid peroxidation and increases in the amounts of olefinic =CH, carbonyl, and methylene groups of lipids. In addition, ionizing radiation induced a decrease in membrane fluidity, disordering of membrane lipids, strengthening of the hydrogen bonding of the phosphate groups of lipid head-groups, and weakening in the hydrogen bonding of the interfacial carbonyl groups of lipids. Radiation further caused significant decrements in the α-helix and turns, and significant increments in the β-sheet and random coil contents in the protein structure. Hierarchical cluster analyses, performed in the whole region (3030-1000 cm(-1)), lipid (3030-2800 cm(-1)), and protein (1700-1600 cm(-1)) regions separately, successfully differentiated the control and irradiated groups of rat brain membranes and showed that proteins in the membranes are affected more than lipids from the damages induced with ionizing radiation. As a result, the current study showed that FT-IR spectroscopy can be used successfully as a novel method to monitor radiation-induced alterations on biological membranes.

Vitamin A deficiency induces structural and functional alterations in the molecular constituents of the rat hippocampus

To date, no structural study has been carried out on the effects of vitamin A deficiency (VAD) on hippocampal macromolecules. Therefore, in the present study, the effect of dietary VAD on the structure, content and function of rat hippocampal molecules was investigated using Fourier transform IF spectroscopy. Male Wistar rats were randomly divided into three groups: an experimental group maintained on a vitamin A-deficient liquid diet (VAD,n7); a control group maintained on a vitamin A-supplemented liquid diet (CON,n9); a pure control group maintained on standard solid laboratory chow (PC,n7). The PC group was included in the study to ensure that the usage of liquid diet did not influence the outcomes of VAD. Both the CON and PC groups were successfully discriminated from the VAD group by principal component analysis and hierarchical cluster analysis. The spectral analysis indicated a significant decrease in the contents of saturated and unsaturated lipids, cholesteryl esters, TAG and nucleic acids in the VAD group when compared with the CON group (P≤ 0·05). In addition, a significant decrease in membrane fluidity and a significant increase in lipid order (e.g. acyl chain flexibility) were observed in the VAD group (P≤ 0·001). The results of the artificial neural network analysis revealed a significant decrease in the α-helix structure content and a significant increase in the turn and random coil structure contents, indicating protein denaturation, in the VAD group when compared with the CON and PC groups (P≤ 0·05). Dietary exclusion of vitamin A for 3 months apparently had an adverse impact on compositional, structural and dynamical parameters. These changes can be due to increased oxidative stress, confirming the antioxidant protection provided by vitamin A when used as a dietary supplement at low-to-moderate doses.

Screening of chemopreventive effect of naringenin-loaded nanoparticles in DMBA-induced hamster buccal pouch carcinogenesis by FT-IR spectroscopy

The aim of the present study is to investigate the chemopreventive effects of the prepared naringenin-loaded nanoparticles (NARNPs) relative to efficacy of free naringenin (NAR) in modifying the functional, structural, and compositional changes at the molecular level during 7, 12-dimethylbenz[a]anthracene (DMBA)-induced hamster buccal pouch (HBP) carcinogenesis by Fourier transform infrared (FT-IR) spectroscopy. The results revealed that a significant increase in the amount of proteins and nucleic acid contents and a decrease in the amount of lipids and glycogen contents are observed in DMBA-induced tumor tissues. In addition, in tumor tissues a decrease in lipid order and a significant increase in membrane dynamics were noticed. Further, the composition and secondary structure of proteins were found to be altered, which indicates some important structural alterations in the existing proteins and/or the expression of new types of proteins occurring under the tumor transformation. Furthermore, oral administration of free NAR and NARNPs significantly increased lipids and their order as well as increased the glycogen contents and decreased the levels of proteins and nucleic acid contents. On a comparative basis, NARNPs were found to have a more potent antitumor effect than free NAR in completely preventing the formation of squamous cell carcinoma and in improving the biochemical constituents to a normal range in DMBA-induced HBP carcinogenesis. The present study further shows a great potential of FT-IR spectroscopy as a complimentary tool for the screening of various anticancer drugs and follow-up, which may allow faster response to critical problems arising during treatment.

Macromolecular Changes in Nilotinib Resistant K562 Cells; an In vitro Study by Fourier Transform Infrared Spectroscopy

Nilotinib is a second generation tyrosine kinase inhibitor which is used in both first and second line treatment of chronic myeloid leukemia (CML). In the present work, the effects of nilotinib resistance on K562 cells were investigated at the molecular level using Fourier transform infrared (FT-IR) spectroscopy. Human K562 CML cells were exposed to step-wise increasing concentrations of nilotinib, and sub-clones of K562 cells resistant to 50 nM nilotinib were generated and referred to as K562/NIL-50 cells. Antiproliferative effects of nilotinib were determined by XTT cell proliferation assay. Changes in macromolecules in parental and resistant cells were studied by FT-IR spectroscopy. Nilotinib resistance caused significant changes which indicated increases in the level of glycogen and membrane/lipid order. The amount of unsaturated lipids increased in the nilotinib resistant cells indicating lipid peroxidation. The total amount of lipids did not change significantly but the relative proportion of cholesterol and triglycerides altered considerably. Moreover, the transcriptional status decreased but metabolic turn-over increased as revealed by the FT-IR spectra. In addition, changes in the proteome and structural changes in both proteins and the nucleus were observed in the K562/NIL-50 cells. Protein secondary structural analyses revealed that alpha helix structure and random coil structure decreased, however, anti-parallel beta sheet structure, beta sheet structure and turns structure increased. These results indicate that the FT-IR technique provides a method for analyzing drug resistance related structural changes in leukemia and other cancer types.