In vivo evaluation of nephrotoxicity and neurotoxicity of colistin formulated with sodium deoxycholate sulfate in a mice model.

Neurotoxicity and nephrotoxicity are the major dose-limiting factors for the clinical use of colistin against multidrug-resistant (MDR) Gram-negative bacteria. This study aimed to investigate the neurotoxic and nephrotoxic effects of colistin formulated with in-house synthesized sodium deoxycholate sulfate (SDCS) in a mouse model. Male mice C57BL/6 were randomly divided into four groups: control (saline solution), colistin (15 mg/kg/day), colistin:SDCS 1:1, and colistin:SDCS 1:2. In the colistin:SDCS treatment groups, the dosage was 15 mg/kg/day colistin equivalent; all mice were treated for 7 successive days. The thermal tolerance, body weight gain and organ weights were measured. The levels of serum blood urea nitrogen (BUN), creatinine (Cr), superoxide dismutase (SOD), and catalase (CAT) were assessed. Histopathological damages were assessed on mice organ. The colistin:SDCS formulations significantly improved thermal pain response of the mice comparable to the control group. The administration did not impair kidney function as evidence from BUN and Cr results; however, the oxidative stress biomarkers decreased in the colistin and colistin-SDCS treated mice. Several abnormalities were observed in the kidney, liver, spleen, and sciatic nerve tissues following colistin treatment, which indicated evidence of toxicity. The colistin-SDCS formulations were associated with less acute toxicity and fewer nephrotoxic and neurotoxic changes compared with the colistin alone group which indicated that SDCS attenuated colistin nephrotoxicity and neurotoxicity. This study highlights the potential application of colistin formulated with SDCS for safer clinical use against MDR Gram-negative bacteria.

Piceatannol-3'-O-ß-D-glucopyranoside attenuates colistin-induced neurotoxicity by suppressing oxidative stress via the NRF2/HO-1 pathway.

BACKGROUND: Multidrug-resistant Gram-negative bacteria are the most pressing problem in treating infectious diseases. As one of the primary drugs for multidrug-resistant Gram-negative bacteria, the neurotoxicity of colistin has become a significant challenge in clinical practice. PURPOSE: This study aimed to investigate the potential effect of piceatannol-3'-O-ß-D glucopyranoside (PG) on colistin-induced neurotoxicity and the underlying mechanism. METHODS: In vitro, nerve cell damage models were established by exposing N2a cells to 400 µM colistin for 24 h. The effects of PG on cell viability, apoptosis level, and oxidative stress level were analyzed. A western blot experiment was performed to determine the NRF2 pathway, apoptosis, and autophagy-related proteins. Mitochondrial morphology and mitochondrial membrane potential were detected after staining using laser confocal microscopy. In vivo, nerve injury mouse model was established by intracerebroventricular colistin administration. Morphological changes in brain tissues were observed using HE and Nissl staining. RESULTS: PG significantly reduced colistin-induced neuronal apoptosis levels. The apoptosis-related protein expressions were suppressed after PG intervention. Mechanistically, PG increased the levels of antioxidant factors and decreased the levels of oxidative factors, which might be related to the activation of the NRF2 pathway. In addition, PG treatment reversed the deviations in mitochondrial morphology and membrane potential. PG suppressed autophagy levels in N2a cells, possibly because PG inhibited colistin-induced apoptosis, thus reducing the level of spontaneous protective autophagy in cells. Nrf2 knockdown N2a cell models were applied to confirm that the activation of the NRF2 pathway played a vital role in PG alleviating the nerve damage caused by colistin. CONCLUSION: PG is a potential treatment option for colistin-induced neurotoxicity. It mitigated colistin-induced oxidative stress-associated injury and mitochondrial damage by activating the NRF2/HO-1 pathway, thus reducing nerve cell apoptosis.

Modulation of miR-205/ EGLN2 by rosuvastatin mitigates colistin-induced nephrotoxicity in rats: Involvement of ATF4/ CHOP and Nrf2 pathways.

Although the beneficial role of microRNA has been investigated thoroughly, the reno-protective role of microRNA-205 (miR-205) against colistin-induced nephrotoxicity has not yet been tackled. Hence, our study sought to study the possible modulatory effect of rosuvastatin on miR-205 and its downstream target, Egl-9 family hypoxia-inducible factor 2 (EGLN2) to combat oxidative and endoplasmic reticulum (ER) stresses as pivotal contributors to colistin-associated renal injury. Rats were randomly divided into four groups; normal, colistin (300 000 IU/Kg/day; i.p), colistin pretreated with rosuvastatin (10 mg/kg; p.o) and colistin pretreated with rosuvastatin (20 mg/kg; p.o) for 6 successive days. Pretreatment with rosuvastatin attenuated renal injury induced by colistin and enhanced kidney function with a marked reduction in renal injury markers, neutrophil gelatinase-associated lipocalin, and kidney injury molecule-1. Besides, rosuvastatin upregulated renal miR-205 expression and suppressed gene expression of EGLN2. In addition, it downregulated ER stress-related genes (activation transcription factor 4 (ATF4) and C/EBP homologous protein (CHOP)) along with caspases 12 and 3. It also induced the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) as detected by immunohistochemical examination besides increased renal antioxidants, reduced glutathione, and superoxide dismutase. In conclusion, rosuvastatin triggered a series of protective mechanisms against colistin-induced nephrotoxicity through modulating miR-205 and EGLN2 expression. Rosuvastatin suppressed ATF4/ CHOP trajectory and activated the Nrf2 pathway to substantiate its antioxidant and anti-apoptotic capacities.

The neuroprotective effect of mesenchymal stem cells in colistin-induced neurotoxicity.

Colistin is an effective antibiotic against multidrug-resistant gram-negative bacterial infections; however, neurotoxic effects are fundamental dose-limiting factors for this treatment. Stem cell therapy is a promising method for treating neuronal diseases. Multipotent mesenchymal stromal cells (MSC) represent a promising source for regenerative medicine. Identification of neuroprotective agents that can be co-administered with colistin has the potential to allow the clinical application of this essential drug. This study was conducted to assess the potential protective effects of MSC, against colistin-induced neurotoxicity, and the possible mechanisms underlying any effect. Forty adult female albino rats were randomly classified into four equal groups; the control group, the MSC-treated group (A single dose of 1 × 106/mL MSCs through the tail vein), the colistin-treated group (36 mg/kg/d colistin was given for 7 d) and the colistin and MSC treated group (36 mg/kg/d colistin was administered for 7 d, and 1 × 106/mL MSCs). Colistin administration significantly increased GFAP, NGF, Beclin-1, IL-6, and TNF-α immunreactivity intensity. MSC administration in colistin-treated rats partially restored each of these markers. Histopathological changes in brain tissues were also alleviated by MSC co-treatment. Our study reveals a critical role of inflammation, autophagy, and apoptosis in colistin-induced neurotoxicity and showed that they were markedly ameliorated by MSC co-administration. Therefore, MSC could represent a promising agent for prevention of colistin-induced neurotoxicity.

Investigation of the nephroprotective effect of dexmedetomidine on colistin-induced nephrotoxicity in rats.

ACKGROUND: There are very few studies in the literature focusing on whether dexmedetomidine exerts a protective effect on colistin nephrotoxicity. Our study aims to investigate the nephroprotective effect of dexmedetomidine in an experimental model of nephrotoxicity in rats. METHODS: The control group was administered saline (SF) intraperitoneally twice a day. The colistin group received an intraperitoneal (ip) injection of 10 mg/kg of colistin twice a day. The DX10 group received 10 mg/kg of colistin 20 minutes after the intraperitoneal injection of 10 mcg/kg of dexmedetomidine. The DX20 group received 10 mg/kg of colistin 20 minutes after the intraperitoneal injection of 20 mcg/kg of dexmedetomidine. Applications were continued for 7 days, twice a day. All rats were sacrificed on the 8th day after blood and kidney tissue samples were taken. BUN, Creatine, KIM-1 and Endothelin-1 were studied in blood samples. RESULTS: There was a significant difference in the median values of Urea, BUN and Creatine between the groups (p<0.001, p<0.001, p<0.001, respectively). There was a significant difference in the median values of KIM-1 and Endothelin-1 between the groups (p=0.009, p=0.001, respectively). A significant difference was observed between the histopathological scores of the groups (p<0.001). CONCLUSION: Dexmedetomidine significantly decreased the elevated levels of BUN, Creatinine, KIM-1, and Endothelin-1 induced by colistin. Dexmedetomidine, at both doses, histopathologically prevented apoptosis and reduced the number of necrotic cells in the kidneys. Dexmedetomidine provides renoprotective effects, therefore it is a valuable sedation agent for clinicians working in intensive care units (Tab. 2, Fig. 4, Ref. 19). Text in PDF www.elis.sk Keywords: rat, colistin, nephrotoxicity, dexmedetomidine.

Efficacy of stem cell-based therapies for colistin-induced nephrotoxicity.

The increase in infections with multidrug resistant bacteria has forced to return to the use of colistin, antibiotic with known nephrotoxicity. Mesenchymal stem cells (MSCs) are being extensively investigated for their potential in regenerative medicine. This study aimed to investigate the possible protective mechanisms of the MSCs against kidney injury induced by colistin. Forty adult female albino rats were randomly classified into 4 equal groups; the control group, the MSC-treated group (a single dose of 1 ×106 /ml MSCs through the tail vein), the colistin-treated group (36 mg/kg/day colistin was given for 7 days), and the both colistin and MSC group (36 mg/kg/day colistin and 1 ×106 /ml MSCs). Main outcome measures were histopathological alterations, kidney malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT) and immunohistological autophagy evaluation. MSC repressed the progression of colistin-induced kidney injury as evidenced by the improvement of histopathological alterations and the substantial increase MDA, and decrease SOD and CAT in serum levels. Moreover, MSC resulted in a profound reduction in oxidative stress as manifested by decreased MDA and increased SOD in serum. Notably, MSC suppressed colistin-induced autophagy; it reduced renal levels of Beclin-1, P62 and LC3A/B. Furthermore, MSC decreased renal levels of eNOS. Lastly, MSC efficiently decreased expression of the TUNEL positive cell number. MSC confers protection against colistin-induced kidney injury by alleviating oxidative stress, nitric oxide synthase besides modulating reducing autophagy and apoptosis.

Colistin-induced pulmonary toxicity involves the activation of NOX4/TGF-ß/mtROS pathway and the inhibition of Akt/mTOR pathway.

Colistin therapy can cause pulmonary toxicity, however, our understanding of the underlying molecular mechanism remains incomplete. This study aimed to investigate the molecular mechanism of colistin-induced pulmonary toxicity in vitro and in vivo. Our results showed that intraperitoneal colistin treatment significantly increased the expression of TGF-ß and NOX4 protein and mRNA, then triggers oxidative stress, mitochondrial dysfunction, and apoptosis in the lung tissue of mice and A549 cells. Moreover, colistin treatment significantly increased levels of mitochondrial ROS (mtROS) and autophagy flux in A549 cells. Inhibition of NOX4 protected A549 cells against colistin-induced mtROS and apoptosis. Colistin treatment also down-regulated the expression of p-Akt and p-mTOR proteins (all P < 0.05 or 0.01) in lung tissues of mice or A549 cells. Inhibition of autophagy or Akt pathways by chloroquine (CQ), 3-Methyladenine (3-MA) or LY294002 promoted colistin-induced mitochondrial damage, and caspase-dependent cellular apoptosis. Whereas, activation of autophagy by rapamycin pretreatment of A549 cells partly abolished colistin-induced cytotoxicity, mitochondrial dysfunction, and apoptosis. This is first study to show that colistin-induced pulmonary toxicity involves the activation of TGF-ß/NOX4/mtROS pathway and the inhibition of Akt/mTOR pathway in lung tissues of mice and highlights the key protective role of autophagy activation.

Delineation of the molecular mechanisms underlying Colistin-mediated toxicity using metabolomic and transcriptomic analyses.

The mechanisms underlying colistin-induced toxicity are not fully understood. This study used untargeted metabolomics and transcriptomics to elucidate the molecular processes occurring in the liver and kidney of rats after treatment with colistin methanesulfonate (CMS). Rats were treated with 50 mg/kg CMS (high-dose), 25 mg/kg CMS (low-dose), or vehicle control, either as a single dose or once daily for 1 or 4 weeks. We found that metabolic alterations were dose- and treatment duration-dependent in the kidney, whereas mild changes were noted in the liver. Metabolic profiles in the high-dose, low-dose, and control groups of both tissues could be classified using partial least-squares discriminant analysis. Metabolic alterations were associated with the citric acid cycle and related processes, disrupted balance between pro-oxidants and antioxidants, inflammatory responses, and amino acid and nucleic acid metabolism. Gene expression profiles further showed that high-dose treatment was associated with disrupted metabolism, oxidative stress, and proinflammatory signals in the kidney. The expression levels of genes related to the cell cycle, DNA replication, and programmed cell death were also predominantly upregulated. These findings suggested that high-dose treatment was associated with a dramatic increase in cellular kidney injury, while only minor effects were observed in the low-dose group. Almost no significant gene expression was changed in the liver, even with high-dose CMS. In conclusion, untargeted metabolomics and transcriptomics provided better insights into the biological mechanisms underlying colistin-induced nephrotoxicity.

Role of silymarin (Silybum marianum) in the prevention of colistin-induced acute nephrotoxicity in rats.

Silymarin (Silybum marianum) has some protective effects against drug toxicity (cisplatin, acetaminophen, adriamycin, gentamicin etc.). Colistin is a strong antimicrobial, which is frequently used in the treatment of resistant gram-negative bacterial infections in recent years although it has nephrotoxic potential. This study was aimed to determine the role of silymarin against colistin-induced acute nephrotoxicity (CIN). Rats were randomly divided into four groups. The control group was treated with tap water whereas groups 2 and 3 received silymarin (orally, 100 mg/kg/day) and colistin (intraperitoneally, 750.000 IU/kg/day) for seven days, respectively. Group 4 received both 750,000 IU/kg/day colistin and 100 mg/kg/day silymarin for seven days. After euthanasia, histopathological and biochemical examinations were completed for the kidney tissue specimens and blood samples. All parameters of the control and silymarin groups were similar. Severe weight loss was seen in the groups receiving colistin (groups 3 and 4). Silymarin significantly increased glutathione peroxidase and superoxide dismutase levels when administered with colistin in group 4 only. Acute tubular injury, tubular necrosis, meduller congestion, interstitial inflammation and apoptotic indices of colistin group were significantly higher than the control group. The administration of colistin with silymarin (group 4) was able to make some improvements in tubular necrosis and significant increase in antioxidant capacity. Silymarin increased antioxidant enzyme activity only when used in combination with colistin. The effects of silymarin may become more pronounced when used at higher doses or with a longer duration of treatment and may prevent nephrotoxicity.

METTL3-mediated M6A methylation modification is involved in colistin-induced nephrotoxicity through apoptosis mediated by Keap1/Nrf2 signaling pathway.

Colistin is a cationic polypeptide antibiotic. Despite its nephrotoxicity, it is still widely used as a last-line antibiotic against infection worldwide with the emergence of multi-drug resistant Gram-negative bacilli. N-methyladenosine (m6A) methylation-mediated degradation of RNA is essential for kidney development. However, m6A methylation impacts not only RNA stability, but also other RNA metabolism processes. How RNA decay affects the nephrotoxicity of colistin is largely unknown. Therefore, in this study, we verified that colistin could induce mouse kidney apoptosis through some apoptotic indicators, and confirmed the relationship between methylation and apoptosis through the detection of m6A methylation, thus elucidating the potential mechanism of colistin nephrotoxicity. The results showed that the renal tubule dilation and tubular structure were observed in the colistin group, and the oxidative stress index and ATPase activities were significantly different from those in the control group. Under electron microscope, the kidney in colistin group showed typical apoptotic morphological changes such as nuclear pyknosis, chromatin edge aggregation, and intact nuclear membrane, accompanied by significant changes in apoptosis-related genes. The level of m6A in the colistin group was significantly decreased, accompanied by downregulation of METTL3 mRNA and protein levels, and METTL3 was significantly correlated with apoptotic gene proteins. Data from this study suggested that m6A methylation was involved in oxidative stress-mediated apoptosis in the mechanism of colistin nephrotoxicity.

Determination of the retinal toxicity of intravitreal colistin in rabbit eyes.

PURPOSE: To determine the possible adverse effects and safe dose range of intravitreal colistin, an antibiotic, after its intravitreal application. METHODS: Twenty eyes of 20 adult male and female New Zealand white rabbits were selected. Various concentrations of colistin were prepared. In each rabbit, 0.1 mL of colistin solution or saline solution was injected intravitreally into the right eye. Electroretinographic recordings were taken before and 2 weeks after injection. Histopathological examination was made using a light microscope following enucleation and fixation procedures. In histopathologic cross-sections, the differences between drug-injected eyes and control eyes were evaluated. RESULTS: Electroretinographic examination showed a decrease of 30% as a significant value in the a and b wave amplitudes of the rabbits that injected 400 µg/0.1 ml and higher concentrations. Histological examination revealed histiocytic infiltration, histiocytic vacuoles, inflammation, and retinal degeneration in rabbit eyes given 400 µg/0.1 ml, 800 µg/0.1 ml, and 1.6 mg/0.1 ml concentrations of colistin. CONCLUSION: Based on our findings, the safe concentration of colistin is 0.2 mg/0.1 ml. Administration of 0.4 mg/0.1 ml was associated with cataract development, electrophysiological depression, and pathological changes in retinal layers.

Toxicologic effect and transcriptome analysis for short-term orally dosed enrofloxacin combined with two veterinary antimicrobials on rat liver.

Presently, toxicological assessment of multiple veterinary antimicrobials has not been performed on mammals. In this study, we assessed the short-term toxicity of enrofloxacin (E) combined with colistin (C) and quinocetone (Q). Young male rats were orally dosed drug mixtures and single drugs in 14 consecutive days, each at the dose of 20, 80, and 400 mg/(kg·BW) for environmental toxicologic study. The results showed that at the high dose treatment, the combination of E + C+Q significantly decreased body intake, lymphocytes count on rats; significantly increased the values of Alanine aminotransferase (ALT), Glutamic oxaloacetic transaminase (AST) and, cholinesterase (CHE); it also got the severest histopathological changes, where sinusoidal congestion and a large number of black particles in sinusoids were observed. This means E + C+Q in the high dose groups was able to cause significant damage to the liver. Other combinations or doses did not induce significant liver damage. Transcriptome analysis was then performed on rats in high dose group for further research. For E + C and E + Q, an amount of 375 and 480 differently expressed genes were filtered out, revealing their possible underlying effect on genomes. For E + C+Q, a weighted gene co-expression network analysis was performed and 96 hub genes were identified to reveal the specific effect induced by this combination. This study indicates that joint toxicity should be taken into consideration when involving the risk assessment of these antimicrobials.

Effect of taxifolin/dapagliflozin combination on colistin-induced nephrotoxicity in rats.

Colistin is an antimicrobial agent that is used in resistant gram-negative infections. Its most common dose-limiting adverse effect is nephrotoxicity. The objective of our study was to explore the possible effects of each of taxifolin and dapagliflozin alone and in combination on colistin-induced nephrotoxicity in rats. Sixty male rats were randomized into six groups: Control; colistin; colistin + taxifolin; colistin + dapagliflozin; colistin + carboxymethyl cellulose (CMC) and colistin + taxifolin + dapagliflozin. Dapagliflozin, taxifolin, and CMC were given daily for 7 days, 4 hours before colistin injection. Kidney weight/body weight ratio and renal function tests were determined. Renal tissue nerve growth factor-ß (NGF-ß), transforming growth factor beta 1 (TGF-ß1), proinflammatory cytokines, nuclear factor (erythroid-derived 2)-like 2 (Nrf2), toll-like receptor 4 (TLR4), nuclear factor kappa B (NF-κB) p65, signal transducer and activator of transcription 3 (STAT3), oxidative stress parameters, beclin-1 and c-Jun NH2-terminal kinase (JNK) activities were measured. Kidneys were examined histopathologically and immunohistochemically. Taxifolin and/or dapagliflozin induced significant improvement in the renal functions and oxidative stress parameters with significant increase in tissue Nrf2, STAT3 and NGF-ß accompanied with significant decrease in kidney weight/body weight ratio, tissue proinflammatory cytokines, TGF-ß1, NF-κB (p65), TLR4, beclin-1 and JNK activities and improved the histopathological picture when compared to rats treated with colistin alone. This improvement was significant with taxifolin/dapagliflozin combination compared to rats treated with each of these agents alone. So, we concluded that the combined use of taxifolin and dapagliflozin may confer a therapeutic tool for attenuation of colistin-induced nephrotoxicity.

Tobramycin and Colistin display anti-inflammatory properties in CuFi-1 cystic fibrosis cell line.

Current cystic fibrosis (CF) treatment strategies are primarily focused on oral/inhaled anti-inflammatories and antibiotics, resulting in a considerable treatment burden for CF patients. Therefore, combination treatments consisting of anti-inflammatories with antibiotics could reduce the CF treatment burden. However, there is an imperative need to understand the potential drug-drug interactions of these combination treatments to determine their efficacy. Thus, this study aimed to determine the interactions of the anti-inflammatory agent Ibuprofen with each of the CF-approved inhaled antibiotics (Tobramycin, Colistin and its prodrug colistimethate sodium/Tadim) and anti-bacterial and anti-inflammatory efficacy. Chemical interactions of the Ibuprofen:antibiotic combinations were elucidated using High-Resolution Mass-Spectrometry (HRMS) and 1H NMR. HRMS showed pairing of Ibuprofen and Tobramycin, further confirmed by 1H NMR whilst no pairing was observed for either Ibuprofen:Colistin or Ibuprofen:Tadim combinations. The anti-bacterial activity of the combinations against Pseudomonas aeruginosa showed that neither paired nor non-paired Ibuprofen:antibiotic therapies altered the anti-bacterial activity. The anti-inflammatory efficacy of the combination therapies was next determined at two different concentrations (Low and High) using in vitro models of NuLi-1 (healthy) and CuFi-1 (CF) cell lines. Differential response in the anti-inflammatory efficacy of Ibuprofen:Tobramycin combination was observed between the two concentrations due to changes in the structural conformation of the paired Ibuprofen:Tobramycin complex at High concentration, confirmed by 1H NMR. In contrast, the non-pairing of the Ibuprofen:Colistin and Ibuprofen:Tadim combinations showed a significant decrease in IL-8 secretion at both the concentrations. Importantly, all antibiotics alone showed anti-inflammatory properties, highlighting the inherent anti-inflammatory properties of these antibiotics.

Antibiotic Cross-linked Micelles with Reduced Toxicity for Multidrug-Resistant Bacterial Sepsis Treatment.

One potential approach to address the rising threat of antibiotic resistance is through novel formulations of established drugs. We designed antibiotic cross-linked micelles (ABC-micelles) by cross-linking the Pluronic F127 block copolymers with an antibiotic itself, via a novel one-pot synthesis in aqueous solution. ABC-micelles enhanced antibiotic encapsulation while also reducing systemic toxicity in mice. Using colistin, a hydrophilic, potent ″last-resort" antibiotic, ABC-micelle encapsulation yield was 80%, with good storage stability. ABC-micelles exhibited an improved safety profile, with a maximum tolerated dose of over 100 mg/kg colistin in mice, at least 16 times higher than the free drug. Colistin-induced nephrotoxicity and neurotoxicity were reduced in ABC-micelles by 10-50-fold. Despite reduced toxicity, ABC-micelles preserved bactericidal activity, and the clinically relevant combination of colistin and rifampicin (co-loaded in the micelles) showed a synergistic antimicrobial effect against antibiotic-resistant strains of Escherichia coli, Pseudomonas aeruginosa, and Acinetobacter baumannii. In a mouse model of sepsis, colistin ABC-micelles showed equivalent efficacy as free colistin but with a substantially higher therapeutic index. Microscopic single-cell imaging of bacteria revealed that ABC-micelles could kill bacteria in a more rapid manner with distinct cell membrane disruption, possibly reflecting a different antimicrobial mechanism from free colistin. This work shows the potential of drug cross-linked micelles as a new class of biomaterials formed from existing antibiotics and represents a new and generalized approach for formulating amine-containing drugs.

Alpha-lipoic acid alleviates colistin nephrotoxicity in rats.

Colistin methanesulfonate (CMS), a clinical form of colistin, is widely used as a last-line treatment for multidrug-resistant (MDR) gram-negative bacterial infections in critically ill patients presenting a considerably high mortality rate. However, nephrotoxicity is considered to be a critical adverse effect that limits CMS's clinical use. Alpha-lipoic acid (ALA) is a strong antioxidant that is effective in preventing nephrotoxicity in many models. The aim of this study was to investigate ALA's ability to protect against nephrotoxicity induced by colistin in rats. Male Wistar albino rats were randomly divided into four groups. Group 1 was the control group (Control; n = 6), in which isotonic saline was administered to the rats. Group 2 was the ALA group (ALA; n = 6) in which rats received 100 mg/kg ALA. Groups 3 was the CMS (CMS; n = 7) in which 450.000 IU/kg/day of CMS was administered to the rats. Groups 4 was the CMS + ALA group (n = 6), in which rats were injected with 100 mg/kg of ALA 30 min before administration of CMS. All injections were performed intraperitoneally at 1, 4, 7, and 10 days. Urine was collected by using a metabolic cage for 24 h after each administration. The rats were euthanized under ether anesthesia after 24 h of the last administration. Blood and kidney samples then were collected for histological and biochemical analysis. ALA pretreatment could reverse the effects of colistin-induced nephrotoxicity, partly through its suppressing effect on Nox4 and caspase-3, which in turn results in its antioxidant and antiapoptotic effect. Therefore, ALA may be an effective strategy for the management of colistin nephrotoxicity.

The effects of hesperidin on colistin-induced reproductive damage, autophagy, and apoptosis by reducing oxidative stress.

This study has been conducted to investigate the effect of hesperidin on colistin-induced reproductive damage in male rats. Twenty-four adult male Sprague Dawley rats were used as animal material. They were divided into four groups: control group, received physiological saline for 7 days by oral gavage; hesperidin group, received 300 mg/kg day hesperidin for 7 days; colistin group, received 73 mg/kg (total dose) colistin during 7 days; and colistin + hesperidin group, received 300 mg/kg day hesperidin following the colistin treatment. At the end of the study, routine spermatological parameters and biochemical evaluations were assayed. Also, apoptosis and autophagy biomarkers in testes were evaluated. Colistin increased oxidative stress, apoptosis and autophagy expression levels in testis. Hesperidin supplementation significantly decreased the oxidative stress levels in the testes of the colistin + hesperidin group when compared to the colistin group. The highest apoptosis and autophagy expression levels were detected in the colistin group. These values were statistically lower in the colistin + hesperidin group when compared to the colistin group. Colistin treatment decreased the percentage of sperm motility and increased sperm abnormality. Hesperidin supplementation mitigated significantly mentioned side effects compared to the colistin group. In conclusion, hesperidin supplementation can be a good strategy to mitigate colistin-induced testicular toxicity.

Exposure to colistin impairs skin keratinocytes and lateral-line hair cells in zebrafish embryos.

Environmental contamination by antibiotics has become a global issue. Colistin, a cationic antimicrobial polypeptide, has been widely used in human/veterinary medicine, and growth promotion in aquaculture. However, no study has been conducted to test the toxic effects of colistin on aquatic animals. In this study, we examined the effects of colistin on zebrafish embryos. Zebrafish embryos were incubated in different concentrations (0, 0.01, 0.1, 1, 2, 3, and 10 µM) of colistin for 96 h. Colistin increased the mortality rate in a dose-dependent manner (LC50 was 3.0 µM or 3.5 mg L-1), but it did not change the hatching rate, heart rate, body length, eye size, or yolk size of embryos. However, colistin impaired keratinocytes and lateral-line hair cells in the skin of embryos. Colistin (at concentrations ≥0.1 µM) decreased the number of FM1-43-labeled hair cells and reduced the mechanotransduction-mediated Ca2+ influx at hair bundles, suggesting that sublethal concentrations of colistin can impair lateral line function. To investigate the lethal injury, morphological changes were sequentially observed in post-hatched embryos subjected to lethal concentrations of colistin. We found that skin keratinocytes were severely damaged and detached after exposure, leading to hypotonic swelling of the yolk sac, loss of ion contents, cell lysis, and eventual death. This study revealed that acute colistin exposure can impair skin cells and pose a threat to fish survival.

Effect of Lipid Emulsion on the Improvement of Renal Damage in Colistin- Induced Nephrotoxicity.

BACKGROUND: Colistin utilization has gradually increased worldwide with the rising of multidrug-resistant (MDR) gram-negative bacilli despite its nephrotoxicity. Lipid emulsion (LE) is widely used for the toxic overdose treatment of various drugs. OBJECTIVE: The aim of the present study is to evaluate the effect of lipid emulsion on the improvement of renal damage in colistin-induced nephrotoxicity with an experimental Sprague Dawley rat model. METHODS: Twenty-four male Sprague Dawley rats were initially assigned to 2 random groups. Sixteen rats were given a single dose of 20 mg/kg colistin, and eight rats received no medication (control group). Sixteen rats that were administered colistin were sub-divided into 2 groups. Group 1/LE rats (n = 8) were given 20 ml/kg solution of lipid emulsion, and group 2/S rats (n = 8) were given 20 ml/kg/day (i.p.) of 0.9% NaCl saline; both were administered for 10 days. Then tubular injury was evaluated histopathologically. Serum levels of blood urea nitrogen (BUN), Kidney Injury Molecule-1 (KIM-1), and creatinine were measured. Besides, malondialdehyde (MDA) levels were determined in tissue samples for the assessment of lipid peroxidation. RESULTS: The mean percent of tubular epithelial cell injury and tubular dilatation was found significantly higher in group 2/S than in control and group 1/LE (p < 0.0001 and < 0.001; respectively). KIM-1 and MDA levels were also statistically higher in group 2/S than in control and group 1/LE. (p < 0.0001 and < 0.0001; respectively). Additionally, serum BUN and creatinine levels of group 2/S were significantly greater than control and group 1/LE (p < 0.0001 and < 0.0001; respectively). CONCLUSION: In this present study, we determined that colistin-induced proximal tubular damage was decreased histopathologically and serologically by the effect of lipid emulsion. Thus, our findings may guide future studies on the clinical use of colistin, particularly in MDR positive intensive care infections.