Boric acid reduces axonal and myelin damage in experimental sciatic nerve injury

Pre- and post-traumatic boric acid therapy prevents oxidative stress-mediated neuronal apoptosis in spinal cord injury

Objectives

In our study, the neuroprotective efficacy of pre- and post-traumatic applications of boric acid (BA) in rats with experimentally induced spinal cord injury (SCI) was investigated.

Materials and Methods

The experimental animals were divided into four groups: control group (C), SCI group (SCI), BA-treated group before SCI (BA+SCI), and BA-treated group after SCI (SCI+BA). Forty-eight hours after SCI, biochemical levels of malondialdehyde (MDA), total oxidant status (TOS), total antioxidant status (TAS), oxidative stress index (OSI), and cytochrome c (Cytc) and caspase-3 (Casp3) expressions were measured in the spinal cord tissues and were examined histologically.

Results

After SCI, oxidative stress markers, such as MDA, TOS, and OSI, and apoptosis markers Cytc and Casp3 showed an increase in levels compared to Group C. The oxidative stress markers that increased after SCI decreased with BA+SCI application, while Cytc level, one of the apoptosis markers that increased after SCI, decreased in both groups with BA application. Cell, myelin, ependymal damage, and hemorrhage levels increased after SCI compared to Group C. These histological markers increased after SCI and decreased after BA+SCI. BA was found to reduce SCI-induced oxidative stress and oxidative stress-induced apoptosis.

Conclusion

BA administered before SCI was shown to be more effective in protecting neural damage.

Investigation of the efficacy of epidermal growth factor, boric acid and their combination in cartilage injury in rats: An experimental study

OBJECTIVES

In this study, we aimed to determine the bioefficacy of epidermal growth factor (EGF), boric acid (BA), and their combination on cartilage injury in rats.

MATERIALS AND METHODS

In in vitro setting, the cytotoxic effects of BA, EGF, and their combinations using mouse fibroblast cell (L929), human bone osteosarcoma cell (Saos-2), and human adipose derived mesenchymal stem cells (hAD-MSCs) were determined by applying MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] test. In in vivo setting, 72 rats were randomly divided into four groups. A standard chondral defect was created and microfracture was performed in all groups. Group A was determined as the control group. In addition to the standard procedure, Group B received 100 ng/mL of EGF, Group C received a combination of 100 ng/mL of EGF and 10 µg/mL of BA combination, and Group D 20 µg/mL of BA.

RESULTS

The cytotoxic effect of the combinations of EGF dilutions (1, 5, 10, 25, 50, 100, 200 ng/mL) with BA (100, 300, 500 µg/mL) was observed only in the 72-h application period and in Saos-2. The cytotoxic effect of BA was reduced when combined with EGF. There was no significant difference in the histopathological scores among the groups (p=0.13).

CONCLUSION

Our study showed that EGF and low-dose BA application had a positive effect on cartilage healing in rats. Significant decreases in recovery scores were observed in the other groups. The combination of EGF and BA promoted osteoblast growth. Detection of lytic lesions in the group treated with 20 µg/mL of BA indicates that BA may have a cytotoxic effect.

An Investigation into the Protective Effects of Various Doses of Boric Acid on Liver, Kidney, and Brain Tissue Damage Caused by High Levels of Acute Alcohol Consumption

Acute high-dose alcohol consumption can lead to oxidative stress, which can cause harm to organs. In this study we aim to determine whether administering boric acid (BA) can protect certain organs (liver, kidney, and brain) from the damaging effects of alcohol by reducing oxidative stress. We used 50 and 100 mg/kg of BA. Thirty-two Sprague Dawley (12-14-week-old) male rats in our study were separated into four groups (n=8); control, ethanol, ethanol+50 mg/kg BA, and ethanol+100 mg/kg BA groups. Acute ethanol was given to rats by gavage at 8 g/kg. BA doses were given by gavage 30 min before ethanol administration. Alanine transaminase (ALT) and aspartate transaminase (AST) measurements were made in blood samples. The total antioxidant status (TAS), total oxidant status (TOS), OSI (oxidative stress index) (TOS/TAS), malondialdehyde (MDA) levels and superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activities were measured to determine the oxidative stress induced by high-dose acute ethanol in the liver, kidney, and brain tissue, and the antioxidant effects of BA doses. According to our biochemical results, acute high-dose ethanol increases oxidative stress in liver, kidney, and brain tissues, while BA reduces the damage in tissues with its antioxidant effect. For the histopathological examinations, hematoxylin-eosin staining was performed. As a result, we found that the effect of alcohol-induced oxidative stress on liver, kidney, and brain tissues was different, and that giving boric acid reduces the increased oxidative stress in tissues due to its antioxidant effect. It was found that 100mg/kg BA administration had a higher antioxidant effect than in the 50mg/kg group.

Crosslinkers for polysaccharides and proteins: Synthesis conditions, mechanisms, and crosslinking efficiency, a review

Polysaccharides and proteins are important macromolecules for developing hydrogels devoted to biomedical applications. Chemical hydrogels offer chemical, mechanical, and dimensional stability than physical hydrogels due to the chemical bonds among the chains mediated by crosslinkers. There are many crosslinkers to synthesize polysaccharides and proteins based on hydrogels. In this review, we revisited the crosslinking reaction mechanisms between synthetic or natural crosslinkers and polysaccharides or proteins. The selected synthetic crosslinkers were glutaraldehyde, carbodiimide, boric acid, sodium trimetaphosphate, N,N'-methylene bisacrylamide, and polycarboxylic acid, whereas the selected natural crosslinkers included transglutaminase, tyrosinase, horseradish peroxidase, laccase, sortase A, genipin, vanillin, tannic acid, and phytic acid. No less important are the reactions involving click chemistry and the macromolecular crosslinkers for polysaccharides and proteins. Literature examples of polysaccharides or proteins crosslinked by the different strategies were presented along with the corresponding highlights. The general mechanism involved in chemical crosslinking mediated by gamma and UV radiation was discussed, with particular attention to materials commonly used in digital light processing. The evaluation of crosslinking efficiency by gravimetric measurements, rheology, and spectroscopic techniques was presented. Finally, we presented the challenges and opportunities to create safe chemical hydrogels for biomedical applications.

Boric acid improves the behavioral, electrophysiological and histological parameters of cisplatin-induced peripheral neuropathy in rats

Boric acid (BA) has been used in many diseases because it increases the amount of reduced glutathione in the body and reduces oxidative damage. This study aims to investigate the effects of boric acid in cisplatin-induced neuropathy, in which oxidative stress is also effective in its pathophysiology. In this study, 8-10 weeks old, 170-190 g Wistar Albino rats were used. Each group contained seven rats (n = 35). Experimental groups consist of control, sham, neuropathy, treatment, and boric acid groups. For the neuropathy model, a single dose of cisplatin (3 mg/kg, i.p) was administered once a week for five weeks, and for the treatment group, boric acid was administered daily (100 mg/kg, intragastric) for five weeks. After drug administration, the rotarod test to evaluate motor performance, the tail-flick and hot/cold plate tests to evaluate sensory conduction states, the von Frey filament test to evaluate the mechanical allodynia, and the adhesive removal test to assess sensorimotor function were performed. The sciatic nerve's motoric conduction velocity was also assessed electrophysiologically. Oxidative stress parameters were also assessed biochemically in sciatic nerve tissue and serum. Hematoxylin and eosin staining was used to evaluate the sciatic nerve tissue histopathologically. The motor conduction velocity of the sciatic nerve, impaired by cisplatin, was increased considerably by boric acid (p < 0.05). It also reduced the latency time of the compound muscle action potential (CMAP), which was increased by cisplatin. (p < 0.05). The von Frey filament test results demonstrated increased pain sensitivity of the cisplatin group increased, and mechanical allodynia was observed. Boric acid significantly alleviated this condition (p < 0.05). In the cold plate, adhesive removal, and rotarod tests, boric acid attenuated the adverse effects of cisplatin (p < 0.05). Biochemically, BA reduced the level of MDA, which was raised by cisplatin, and significantly increased the level of SOD, which was lowered by cisplatin (p < 0.05). Histopathologically; BA reduced neuronal degeneration and vacuolization caused by cisplatin. As a consequence, it has been determined that boric acid alleviates the adverse effects of cisplatin. BA reduced the destructive effect of cisplatin by reducing oxidative stress, and this effect was verified electrophysiologically, behaviorally, and histopathologically.

Influence of galantamine on peripheral nerve degeneration after experimental compression injury of the rat sciatic nerve

BACKGROUND

Galantamine is well-known for its neuroprotective effects and is currently used in the treatment of individuals with Alzheimer's disease. In this study, we induced experimental sciatic nerve injury (SCI) in rats to test the beneficial effects of galantamine.

METHODS

Thirty male Wistar albino rats were divided into three groups, as follows: sham, SCI + saline, and SCI + galantamine. After the administration of an intraperitoneal ketamine and xylazine mixture, which was used for anesthesia, SCI was induced by sur-gical clip compression at the midthigh region of the rats. After surgery, a single daily intraperitoneal dose of galantamine was adminis-tered for 7 days, and nerve tissue sections were obtained 1 week after injury. Histopathology studies were performed to assess neural thickness and apoptotic cell counts, and light microscopic morphological examination was used to determine a potential beneficial effect of galantamine on peripheral nerve degeneration.

RESULTS

We observed a markedly increased microvasculature, increased nerve fiber thickness, and a statistically significant increase in apoptotic cell counts distal to the level of injury in the saline group compared with the sham group. However, the increases in nerve fiber thickness and apoptotic cell counts were less in the galantamine group compared with the saline group.

CONCLUSION

In our experimental model, pharmacological intervention with galantamine demonstrated a protective effect on degeneration after peripheral nerve injury.

Surgical Procedures Required for Measurement Reduce Nerve Conduction Velocity: An In Vivo and In Vitro Comparative Study

Background: Although in vitro methods have disadvantages, they are still commonly used to measure nerve conduction velocity (NCV) in experimental studies. Therefore, this study was designed to demonstrate the effect of the surgical procedures required for in vitro methods on nerve fibers and the effect of in vivo and in vitro methods on the results of electrophysiological measurements.Methods: Rats were assigned to the in vivo (control-1, injury-1, and diabetic-1) and in vitro (control-2, injury-2, and diabetic-2) groups. The NCV and compound action potential amplitudes were measured, and the nerve fibers were histologically examined.Results: Damaged axons and myelin sheaths were observed in the control-2 group. The electrophysiological values of the in vitro groups were lower than those of the in vivo groups. Furthermore, these values were lower for the diabetic and injury groups than for the control groups.Conclusions: This study showed that the surgical procedures required for the in vitro method reduced the measured values. Owing to the previous and current disadvantages of the in vitro method, the in vivo method was more sensitive for the NCV measurement. Moreover, measurements can be performed using the current in vivo method for small nerve fibers.

Cyclophosphamide induced oxidative stress, lipid per oxidation, apoptosis and histopathological changes in rats: Protective role of boron

BACKGROUND

Cyclophosphamide (CP) is an alkylating chemotherapeutic drug used in the treatment of many types of cancer. However, as with other chemotherapeutic drugs, the use of CP is limited by the damage to healthy tissues such as testes, bladder and liver as well as cancerous tissue. Boron (B) is a trace element with many biological properties such as antioxidant, anti-apoptotic and anti-lipid per oxidation.

METHODS

This current study aims to determine protective effects of B on CP induced testicular toxicity. The rats were divided into 4 groups (control, CP, B and B plus CP groups). The testes of experimental animals were taken for histological, apoptotic markers and biochemical analysis.

RESULTS

The damage to some seminifer tubules, loss of typical appearance, thinning of seminifer epithelium and relative enlargement of the tubule lumen were watched in testis of the group that administrated CP. Moreover, Bcl-2, TAC and GSH levels decreased while TOC, OSI, MDA, Bax and Caspase-3 levels increased. On the other hand, pretreatment limited to B in the B plus CP group, testicular tissue improved. In addition, Bcl-2, GSH, TAC levels increased, Bax, MDA, TOC, OSI and caspase-3 levels decreased.

CONCLUSION

B significantly reduced testicular lipid per-oxidation and strengthened antioxidant defenses. Our results showed that pre-treatment B can protect rat testis against CP-induced testicular damage owing to its anti-lipid per oxidation, anti-oxidant and anti-apoptotic properties.

Bioactive Glasses and Glass/Polymer Composites for Neuroregeneration: Should We Be Hopeful?

Bioactive glasses (BGs) have been identified as highly versatile materials in tissue engineering applications; apart from being used for bone repair for many years, they have recently shown promise for the regeneration of peripheral nerves as well. They can be formulated in different shapes and forms (micro-/nanoparticles, micro-/nanofibers, and tubes), thus potentially meeting the diverse requirements for neuroregeneration. Mechanical and biological improvements in three-dimensional (3D) polymeric scaffolds could be easily provided by adding BGs to their composition. Various types of silicate, borate, and phosphate BGs have been examined for use in neuroregeneration. In general, BGs show good compatibility with the nervous system compartments both in vitro and in vivo. Functionalization and surface modification plus doping with therapeutic ions make BGs even more effective in peripheral nerve regeneration. Moreover, the combination of BGs with conductive polymers is suggested to improve neural cell functions at injured sites. Taking advantage of BGs combined with novel technologies in tissue engineering, like 3D printing, can open new horizons in reconstructive approaches for the nervous system. Although there are great potential opportunities in BG-based therapies for peripheral nerve regeneration, more research should still be performed to carefully assess the pros and cons of BGs in neuroregeneration strategies.

Effects of boric acid feeding on the oxidative stress parameters in testes, sperm parameters and DNA damage in mice

This study was aimed to determine the effects of boric acid on oxidative stress, testicular tissue and spermatozoon DNA. Experiments were performed with Swiss Albino mice divided equally into two groups based on the tratment period: one for 4 and the other for 6-week duration. These groups were further divided into subgroups as Control and those administered daily at oral doses of 115 mg/kg, 250 mg/kg and 450 mg/kg of boric acid. Then, testicular tissue were examined postmortem and analyzed using ex-vivo biochemical tools for oxidative stress, spermatozoon membrane integrity, sperm motility and live cell rate (%). In both 4 and 6-week groups, v. seminalis weight, membrane integrity, motility, live cells and GSH levels exhibited a decreasing trent compared to the controls. In addition, 6-week group had a decrease in SOD level. MDA level was higher in controls in both 4 and 6-week groups. Spermatozoon DNA was intact in the 4-week group, but damaged in the 6-week group, and the degree of the damage dependent on the administered dose. Boric acid induces oxidative stress in testicular tissue, and its long-term application (only 6 weeks) caused damage in spermatozoon DNA.

Regeneration of nerve crush injury using adipose-derived stem cells: A multimodal comparison

Introduction: To restore full function following nerve crush injuries is critical but challenging. In an attempt to develop a viable therapy, we evaluated the effect of rat adipose‐derived stem cells (rASC) in 2 different settings of a sciatic crush injury model. Methods: In the first group, after 14 days of nerve crush injury, rASCs were injected distal to the lesion under ultrasound guidance. In the other group, alleviation of compression through clip removal (CR) was combined with epineural injection of rASCs. Gait analyses, MRI, gastrocnemius muscle weight ratio (MWR), and histomorphometry were performed for outcome analysis. Results: CR combined with rASC injection resulted in less muscle atrophy, as evidenced by MWR. These findings are further supported by better functional and anatomical outcomes. Discussion: Animals treated with CR and epineural stem cell injection showed enhanced anatomical and functional recovery. Muscle Nerve58: 566–572, 2018

Effects of boron-containing compounds on immune responses: review and patenting trends

INTRODUCTION

Boron-containing compounds induce effects on immune responses. Such effects are interesting to the biomedical field for the development of therapeutic tools to modulate the immune system.

AREAS COVERED

The scope of BCC use to modify immune responses is expanding, mainly with regard to inflammatory diseases. The information was organized to demonstrate the breadth of reported effects. BCCs act as modulators of innate and adaptive immunity, with the former including regulation of cluster differentiation and cytokine production. In addition, BCCs exert effects on inflammation induced by infectious and noninfectious agents, and there are also reports regarding their effects on mechanisms involving hypersensitivity and transplants. Finally, the authors discuss the beneficial effects of BCCs on pathologies involving various targets and mechanisms.

EXPERT OPINION

Some BCCs are currently used as drugs in humans. The mechanisms by which these BCCs modulate immune responses, as well as the required structure-activity relationship for each observed mechanism of action, should be clarified. The former will allow for the development of improved immunomodulatory drugs with extensive applications in medicine. Patenting trends involve claims concerning the synthesis and actions of identified molecules with a defined profile regarding cytokines, cell differentiation, proliferation, and antibody production.

Turning Fear of Boron Toxicity into Boron-containing Drug Design

BACKGROUND

Despite the historical employment of boron-containing compounds (BCCs) with medicinal purposes, the reported cases of BCC toxicity in humans during the twentieth-century drived us towards a "boron-withdrawal" period. Fortunately, the use of boric acid for specific purposes remains, and the discovery of natural BCCs with biological action attractive for therapeutic purposes as well as the introduction of some new BCCs for clinical use has reactivated the interest in studying the properties of these BCCs.

METHODS

We carried out a structured search of bibliographic databases for scientific peerreviewed research literature regarding boron toxicity and linked that information to that of BCCs in drug design and development. A deductive qualitative content analysis methodology was applied to analyse the interventions and findings of the included studies using a theoretical outline.

RESULTS

This review recapitulates the following on a timeline: the boron uses in medicine, the data known about the toxicological profiles of some BCCs, the pharmacological properties of some BCCs that are employed in cancer and infectious disease therapies, and the known properties of BCCs recently introduced into clinical assays as well as the identification of their structure-activity relationships for toxicity and therapeutic use. Then, we discuss the use of new approaches taking advantage of some toxicological data to identify potent and efficient BCCs for prevention and therapy while limiting their toxic effects.

CONCLUSION

Data for boron toxicity can be strategically used for boron-containing drug design.

The effect of acute dissociation on the electrophysiological properties of rat dorsal root ganglion neurons

The acutely dissociated neurons from the dorsal root ganglia (DRGs) are extensively used. The effects of acute dissociation on the properties of these neurons are, however, not clear. In this study, the action potentials (APs) were recorded from both acutely dissociated and in vivo identified DRG neurons with patch clamp and sharp electrode recording techniques, respectively. We found that acute dissociation slowed both the depolarizing and repolarizing rate of APs, and elongated the AP duration (APD). The lower recording temperature presented in the acutely dissociated neurons contributed to about 10% of these differences. The major contributor of these differences was possibly modulation of the mRNA expression especially those of the ion channels, as suggested by our observation that acute dissociation significantly reduced the mRNA abundance of Nav1.6-1.9. In conclusion, acute dissociation altered the electrophysiological properties of the DRG neurons; the disrupted gene-expression pattern may contribute to this effect.

Analysis of transcriptome sequencing of sciatic nerves in Sprague-Dawley rats of different ages

An aging-induced decrease in Schwann cell viability can affect regeneration following peripheral nerve injury in mammals. It is therefore necessary to investigate possible age-related changes in gene expression that may affect the biological function of peripheral nerves. Ten 1-week-old and ten 12-month-old healthy male Sprague-Dawley rats were divided into young (1 week old) and adult (12 months old) groups according to their ages. mRNA expression in the sciatic nerve was compared between young and adult rats using next-generation sequencing (NGS) and bioinformatics (n = 4/group). The 18 groups of differentially expressed mRNA (DEmRNAs) were also tested by quantitative reverse transcription polymerase chain reaction (n = 6/group). Results revealed that (1) compared with young rats, adult rats had 3608 groups of DEmRNAs. Of these, 2684 were groups of upregulated genes, and 924 were groups of downregulated genes. Their functions mainly involved cell viability, proliferation, differentiation, regeneration, and myelination. (2) The gene with the most obvious increase of all DEmRNAs in adult rats was Thrsp (log₂ FC = 9.01, P < 0.05), and the gene with the most obvious reduction was Col2a1 (log₂FC = –8.89, P < 0.05). (3) Gene Ontology analysis showed that DEmRNAs were mainly concentrated in oligosaccharide binding, nucleotide-binding oligomerization domain containing one signaling pathway, and peptide-transporting ATPase activity. (4) Analysis using the Kyoto Encyclopedia of Genes and Genomes showed that, with increased age, DEmRNAs were mainly enriched in steroid biosynthesis, Staphylococcus aureus infection, and graft-versus-host disease. (5) Spearman's correlation coefficient method for evaluating NGS accuracy showed that the NGS results and quantitative reverse transcription polymerase chain reaction results were positively correlated (r_s = 0.74, P < 0.05). These findings confirm a difference in sciatic nerve gene expression between adult and young rats, suggesting that, in peripheral nerves, cells and the microenvironment change with age, thus influencing the function and repair of peripheral nerves.

The antioxidant and antiapoptotic effect of boric acid on hepatoxicity in chronic alcohol-fed rats

The harmful use of alcohol is a worldwide problem involving all ages. This study aims to investigate chronic alcohol exposure related hepatotoxicity on the rat liver and possible hepatoprotective effects of boric acid. Rats were separated into 4 different groups: control, ethanol, ethanol+boric acid, and boric acid. We measured (i) malondialdehyde (MDA), total sialic acid (TSA), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) levels, which are known to be the markers of alcohol damage; and also (ii) caspase-3, tumor necrosis factor-alpha (TNF-α), and the terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) as the markers of apoptosis. In the ethanol group, MDA, TSA, and TNF-α levels increased whereas SOD and CAT levels decreased compared with the control group. Ethanol+boric acid group MDA, TSA, caspase-3, and TNF-α levels decreased whereas SOD and CAT levels increased compared with the ethanol group. Using histopathological evaluation of light microscope images, immunohistochemical caspase-3 and TNF-α activity in the ethanol+boric acid group were shown to be decreased compared with that in the ethanol group. Our results revealed that ethanol is capable of triggering oxidative stress and apoptosis in the rat liver. We propose that boric acid is an effective compound in protecting the rat liver against ethanol.

Establishing a reliable gait evaluation method for rodent studies

BACKGROUND

CatWalk is one of the most popular tools for evaluating gait recovery in preclinical research, however, there is currently no consensus on which of the many gait parameters captured by CatWalk can reliably model recovery. There are conflicting interpretations of results, along with many common but seldom reported problems such as heel walking and poor compliance.

NEW METHOD

We developed a systematic manual classification method that overcomes common problems such as heel walking and poor compliance. By correcting automation errors and removing inconsistent gait cycles, we isolated stretches of recordings that are more reliable for analysis. Recovery outcome was also assessed by quantitative histomorphometric analysis of myelinated axons.

RESULTS

While 40-60% of runs were erroneously classified without manual intervention, we corrected all errors with our new method, and showed that Stand Time, Duty Cycle, and Swing Speed are able to track significant differences over time and between experimental groups (all p<0.05). The usability of print area and intensity parameters requires further validation beyond the capabilities of CatWalk.

COMPARISON WITH EXISTING METHOD(S)

There is currently no strategy that addresses problems such as heel walking and poor compliance, and therefore no standard set of parameters that researchers can rely on to report their findings.

CONCLUSION

Manual classification is a crucial step to generate reliable CatWalk data, and Stand Time, Duty Cycle, and Swing Speed are suitable parameters for evaluating gait recovery. Static parameters such as print area and intensity should be used with extreme caution.