Evaluation of topical application and systemic administration of rosuvastatin in preventing epidural fibrosis in rats

Postoperative Epidural Fibrosis: Challenges and Opportunities - A Review

Postoperative epidural fibrosis (EF) is still a major limitation to the success of spine surgery. Fibrotic adhesions in the epidural space, initiated via local trauma and inflammation, can induce difficult-to-treat pain and constitute the main cause of failed back surgery syndrome, which not uncommonly requires operative revision. Manifold agents and methods have been tested for EF relief in order to mitigate this longstanding health burden and its socioeconomic consequences. Although several promising strategies could be identified, few have thus far overcome the high translational hurdle, and there has been little change in standard clinical practice. Nonetheless, notable research progress in the field has put new exciting avenues on the horizon. In this review, we outline the etiology and pathogenesis of EF, portray its clinical and surgical presentation, and critically appraise current efforts and novel approaches toward enhanced prevention and treatment.

Metformin-grafted polycaprolactone nanoscaffold targeting sensory nerve controlled fibroblasts reprograming to alleviate epidural fibrosis

Epidural fibrosis (EF), associated with various biological factors, is still a major troublesome clinical problem after laminectomy. In the present study, we initially demonstrate that sensory nerves can attenuate fibrogenic progression in EF animal models via the secretion of calcitonin gene-related peptide (CGRP), suggesting a new potential therapeutic target. Further studies showed that CGRP could inhibit the reprograming activation of fibroblasts through PI3K/AKT signal pathway. We subsequently identified metformin (MET), the most widely prescribed medication for obesity-associated type 2 diabetes, as a potent stimulator of sensory neurons to release more CGRP via activating CREB signal way. We copolymerized MET with innovative polycaprolactone (PCL) nanofibers to develop a metformin-grafted PCL nanoscaffold (METG-PCLN), which could ensure stable long-term drug release and serve as favorable physical barriers. In vivo results demonstrated that local implantation of METG-PCLN could penetrate into dorsal root ganglion cells (DRGs) to promote the CGRP synthesis, thus continuously inhibit the fibroblast activation and EF progress for 8 weeks after laminectomy, significantly better than conventional drug loading method. In conclusion, this study reveals the unprecedented potential of sensory neurons to counteract EF through CGRP signaling and introduces a novel strategy employing METG-PCLN to obstruct EF by fine-tuning sensory nerve-regulated fibrogenesis.

Cinnamaldehyde has Antifibrotic Effects on Rats with Epidural Fibrosis

BACKGROUND

Laminectomy is a widely employed surgical procedure for the treatment of spinal stenosis, but it may lead to epidural fibrosis (EF) and failed back surgery syndrome. Cinnamaldehyde, a phenylpropanoid found in cinnamon, has demonstrated antioxidant and anti-inflammatory properties. In the present study, we hypothesized that topical application and systemic administration of cinnamaldehyde could be helpful in the prevention of EF in a rat laminectomy model.

METHODS

The rats were randomly assigned to control, local, and systemic Tween-80 and local and systemic cinnamaldehyde experimental groups (n = 6, per group). In the control group, just laminectomy was performed. In local treatment groups, applications were done just after the laminectomy onto dura. In systemic treatment groups, intraperitoneal administrations were performed following skin suturing. The degree of epidural fibrosis was evaluated macroscopically and histopathologically 4 weeks later.

RESULTS

Macroscopic assessment revealed decreased EF with both topical and systemic cinnamaldehyde application, whereas microscopic examination results were not significant.

CONCLUSIONS

Our findings provide the first experimental evidence of cinnamaldehyde's potential protective effects against EF.

Pharmacotherapies to prevent epidural fibrosis after laminectomy: a systematic review of in vitro and in vivo animal models

BACKGROUND CONTEXT

Excessive production of epidural fibrosis in the nerve root can be a pain source after laminectomy. Pharmacotherapy is a minimally invasive treatment option to attenuate epidural fibrosis by suppressing proliferation and activation of fibroblasts, inflammation, and angiogenesis, and inducing apoptosis.

PURPOSE

We reviewed and tabulated pharmaceuticals with their respective signaling axes implicated in reducing epidural fibrosis. Additionally, we summarized current literature for the feasibility of novel biologics and microRNA to lessen epidural fibrosis.

STUDY DESIGN/SETTING

Systematic Review.

METHODS

According to the PRISMA guidelines, we systematically reviewed the literature in October 2022. The exclusion criteria included duplicates, nonrelevant articles, and insufficient detail of drug mechanism.

RESULTS

We obtained a total of 2,499 articles from PubMed and Embase databases. After screening the articles, 74 articles were finally selected for the systematic review and classified based on the functions of drugs and microRNAs which included inhibition of fibroblast proliferation and activation, pro-apoptosis, anti-inflammation, and antiangiogenesis. In addition, we summarized various pathways to prevent epidural fibrosis.

CONCLUSION

This study allows a comprehensive review of pharmacotherapies to prevent epidural fibrosis during laminectomy.

CLINICAL SIGNIFICANCE

We expect that our review would enable researchers and clinicians to better understand the mechanism of anti-fibrosis drugs for the clinical application of epidural fibrosis therapies.

Chronic pain after spine surgery: Insights into pathogenesis, new treatment, and preventive therapy

Chronic pain after spine surgery (CPSS) is often characterized by intractable low back pain and/or radiating leg pain, and has been reported in 8-40% of patients that received lumbar spine surgery. We conducted a literature search of PubMed, MEDLINE/OVID with a focus on studies about the etiology and treatments of CPSS and low back pain. Our aim was to provide a narrative review that would help us better understand the pathogenesis and current treatment options for CPSS. This knowledge will aid in the development of optimal strategies for managing postoperative pain symptoms and potentially curing the underlying etiologies. Firstly, we reviewed recent advances in the mechanistic study of CPSS, illustrated both structural (e.g., fibrosis and scaring) and non-structural factors (e.g., inflammation, neuronal sensitization, glial activation, psychological factor) causing CPSS, and highlighted those having not been given sufficient attention as the etiology of CPSS. Secondly, we summarized clinical evidence and therapeutic perspectives of CPSS. We also presented new insights about the treatments and etiology of CPSS, in order to raise awareness of medical staff in the identification and management of this complex painful disease. Finally, we discussed potential new targets for clinical interventions of CPSS and future perspectives of mechanistic and translational research. CPSS patients often have a mixed etiology. By reviewing recent findings, the authors advocate that clinicians shall comprehensively evaluate each case to formulate a patient-specific and multi-modal pain treatment, and importantly, consider an early intraoperative intervention that may decrease the risk or even prevent the onset of CPSS.

Translational potential statement

CPSS remains difficult to treat. This review broadens our understanding of clinical therapies and underlying mechanisms of CPSS, and provides new insights which will aid in the development of novel mechanism-based therapies for not only managing the established pain symptoms but also preventing the development of CPSS.

The Preventive Effect of Decorin on Epidural Fibrosis and Epidural Adhesions After Laminectomy

Laminectomy is commonly performed to treat degenerative spinal diseases by reducing compression on the spinal cord and nerve roots. The postoperative epidural fibrosis and epidural adhesions may result in failed back surgery syndrome, which is characterized by the symptoms of lower back pain or leg pain. There is currently no satisfactory treatment for this complication. The pathological processes of epidural fibrosis and epidural adhesions are relevant to the proliferation of fibroblasts, transdifferentiation of fibroblasts into myofibroblasts, and the excessive deposition of extracellular matrix (ECM) protein. According to reports, transforming growth factor-β1 (TGF-β1) played a vital role in the development of fibrosis by promoting aforementioned processes. Decorin, an endogenous proteoglycan and natural inhibitor of TGF-β1, has exhibited prominent anti-fibrosis activity in various scar formation and fibrosis models of many organs. However, the preventive effect of decorin on epidural fibrosis and epidural adhesions requires further investigation. Here, we investigated the therapeutic effects and potential mechanisms of decorin on epidural fibrosis and epidural adhesions. Our results indicated that decorin could significantly suppress the TGF-β1-induced proliferation, transdifferentiation, and extracellular matrix production in primary fibroblasts. Furthermore, Smad2/3 signaling pathway had been demonstrated to be involved in the preventive effect of decorin. Moreover, administration of decorin in vivo could notably inhibit epidural fibrosis and epidural adhesions after laminectomy. To date, there is no approved therapy to target TGF-β1 for the treatment of epidural fibrosis and epidural adhesions after laminectomy. Our research proved the anti-fibrosis effect of decorin, which may provide an effective and promising treatment for epidural fibrosis and epidural adhesions.

Effect of Cerebrospinal Fluid on Fibroblasts Concerning Epidural Fibrosis: An In Vitro Study

One of the most common treatments for lumbar disc herniation and other lumbar disorders is lumbar laminectomy. There may be some unwanted and serious complications with this procedure such as the “failed back surgery syndrome (FBSS)”. Epidural fibrosis (EF), mainly due to fibroblast proliferation, emerges as the main cause of failed back surgery syndrome. According to the current literature and practice techniques, different agents are being used to prevent EF formation. To date there is no single agreed upon treatment method of EF. In this study, dilutional effect of CSF, together with low potassium levels, on primary skin fibroblast cultures was studied as a possible material for EF prevention. CSF at different concentrations (0-100%) were tested to see its effect on Skin fibroblast proliferation. A wound healing assay was also performed to see the effect of CSF on wound healing. The cell proliferation goes up from 24h to 72hr in all CSF percentages from 0-75% but the proliferation was inhibited at 100% CSF. The “wound” is closed successfully in all CSF percentages between 0-75. The 100% CSF fails to completely close the wound. Adverse effects of low concentrations of potassium levels and dilutional effect of CSF may be a promising solution in the prevention of EF. Further in vivo and in vitro experiments are required to characterize its use.

Refinement of the spinal cord injury rat model and validation of its applicability as a model for memory loss and chronic pain

BACKGROUND

Laminectomy produces trauma in spinal cord injury (SCI) animal models resulting in impinging artefacts and welfare issues. Mechanizing laminectomy using a dental burr assisted (DBA) technique to reduce the impact of conventionally performed laminectomy on animal welfare without any alterations in the outcome of the model was previously demonstrated. However, further validation was necessary to establish it as an alternative in developing SCI rats as a model of chronic pain and memory loss.

NOVEL METHOD

DBA technique was employed to perform laminectomy at T10-T11 vertebrae in rats undergoing contusion SCI as a model of chronic pain and memory loss. In a 56-day study, 24 female Wistar rats (Crl: WI) were assigned randomly to four equal groups: conventionally laminectomised, DBA laminectomised, conventionally laminectomised with SCI and DBA laminectomised with SCI.

RESULTS

The study revealed DBA technique to cause less surgical bleeding (p = 0.001), lower Rat Grimace Scale (p = 0.0006); resulted in better body weight changes (p = 0.0002 on Day 7 and p = 0.0108 on Day 28) and dark phase activity (p = .0.0014 on Day 1; p = 0.0422 on Day 56). Different techniques did not differ in Basso Beattie Bresnahan score, novel object recognition, mechanical allodynia, number of surviving neurons and the area of vacuolation- indicating that the new method doesn't affect the validity of the model.

COMPARISON WITH EXISTING METHODS

In comparison with the conventional technique, motorised laminectomy can be a valid tool that evokes lesser pain and ensures higher well-being in rats modelled for chronic pain and memory loss.

CONCLUSIONS

The intended outcome from the model is not influenced by techniques whereas the DBA-technique is a refined alternative to the conventional method in achieving better welfare in SCI studies.

A novel controlled release tetrandrine-loaded PDLLA film: evaluation of drug release and anti-adhesion effects in vitro and in vivo

To investigate the drug release and anti-adhesion effects of a TET (tetrandrine)-loaded PDLLA (poly-dl-lactide) film. Detection of TET release in vitro was carried out by high-performance liquid chromatography (HPLC) every 2 days following immersion of the tetrandrine-loaded PDLLA film in simulated body fluid until the TET content of the eluate could not be detected. For the in vivo test, TET-loaded PDLLA films were implanted into animal laminectomy models and positive and blank control groups were also set up. Postoperative serum tests, and macroscopic and histological analyses at 1, 4, 8, and 12 weeks, were used to assess the effects of the film. Statistical analyses were performed by one-way ANOVA. The drug release of the tetrandrine-loaded PDLLA film in vitro showed two phases with a second release peak. Ultimately, the duration of continuous delivery was up to 66 days and the cumulative delivery rate was up to 93.18%. Scores for the proliferation of epidural scars or adhesion of the dura mater in the test group were much lower than those for the two control groups. Histological analysis revealed the test group had fewer inflammatory cells and fibroblasts, as well as fewer extracellular collagen fibers, and a lower histology score than those of the two control groups at all time points. Tetrandrine-loaded PDLLA film is a novel controlled drug release and anti-adhesion material in vitro and in vivo.

Multifunctional Supramolecular Hydrogel for Prevention of Epidural Adhesion after Laminectomy

Postoperative epidural adhesion remains a clinically challenging problem in spine surgery. Currently there are no effective and safe antifibrotic and antiadhesion biomaterials that have been specifically developed for this complication in clinical practice. Herein we designed and engineered an advanced antiadhesion hydrogel with multiple functionalities, including temperature-responsive gelation, self-healing, tissue adhesiveness, antioxidation, anti-inflammation, and antifibrosis. This multifunctional supramolecular hydrogel can be facilely constructed by integrating three functional modules, i.e., a thermosensitive triblock copolymer, poloxamer 407 (PX); a reactive oxygen species-eliminating and anti-inflammatory nanoparticle (TPCD NP); and an adhesion-enhancing compound, tannic acid (TA). The optimal formulation (PXNT) was hierarchically screened based on in vitro properties and in vivo activities. Therapeutically, local treatment with PXNT hydrogel effectively prevented epidural fibrosis and adhesion after laminectomy in both rats and rabbits. Of note, PXNT hydrogel showed more beneficial efficacy than different control thermosensitive hydrogels and a commercially available barrier product, Interceed. Mechanistically, PXNT hydrogel significantly attenuated local oxidative stress, inhibited inflammatory responses, and reduced fibrotic tissue formation. Moreover, treatment with PXNT hydrogel did not cause systemic adverse effects and neurological symptoms. Consequently, PXNT hydrogel is a highly promising biomaterial for preventing postlaminectomy epidural adhesion and adhesions after other surgeries.

Response surface optimization of biocompatible elastic nanovesicles loaded with rosuvastatin calcium: enhanced bioavailability and anticancer efficacy

Statins are mainly used for the treatment of hyperlipidemia, but recently, their anticancer role was extremely investigated. The goal of this study was to statistically optimize novel elastic nanovesicles containing rosuvastatin calcium to improve its transdermal permeability, bioavailability, and anticancer effect. The elastic nanovesicles were composed of Tween® 80, cetyl alcohol, and clove oil. The nanodispersions were investigated for their entrapment efficiency, particle size, zeta potential, polydispersity index, and elasticity. The optimized elastic nanovesicular dispersion is composed of 20% cetyl alcohol, 53.47% Tween 80, and 26.53% clove oil. Carboxy methylcellulose was utilized to convert the optimized elastic nanovesicular dispersion into elastic nanovesicular gels. Both the optimized dispersion and the optimized gel (containing 2% w/v carboxymethylcellulose) were subjected to in vitro release study, scanning and transmission electron microscopy, histopathological evaluation, and ex vivo permeation. The cell viability assay of the optimized gel on MCF-7 and Hela cell lines showed significant antiproliferative and potent cytotoxic effects when compared to the drug gel. Moreover, the optimized gel accomplished a significant increase in rosuvastatin bioavailability upon comparison with the drug gel. The optimized gel could be considered as a promising nanocarrier for statins transdermal delivery to increase their systemic bioavailability and anticancer effect. Graphical abstract.

Prospective application of stem cells to prevent post-operative skeletal fibrosis

Post-operative skeletal fibrosis is considered one of the major complications causing dysfunction of the skeletal system and compromising the outcomes of clinical treatment. Limited success has been achieved using current therapies; more effective therapies to reduce post-operative skeletal fibrosis are needed. Stem cells possess the ability to repair and regenerate damaged tissue. Numerous studies show that stem cells serve as a promising therapeutic approach for fibrotic diseases in tissues other than the skeletal system by inhibiting the inflammatory response and secreting favorable cytokines through activating specific signaling pathways, acting as so-called medicinal signaling cells. In this review, current therapies are summarized for post-operative skeletal fibrosis. Given that stem cells are used as a promising therapeutic approach for fibrotic diseases, little effort has been undertaken to use stem cells to prevent post-operative skeletal fibrosis. This review aims at providing useful information for the potential application of stem cells in preventing post-operative skeletal fibrosis in the near future. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1236-1245, 2019.

Inflammation by activated macrophage-like THP-1 cells increases human dura mater cell adhesion with alteration of integrin α2 β1 and matrix metalloproteinase

This study was designed to investigate (i) extracellular matrix to specify adhesive substrates to human dura mater cell (hDMC); (ii) the alteration on adhesion-related molecules in hDMC; and (iii) secreted matrix metalloproteinases (MMPs) linked with extracellular matrix remodeling after exposure to inflammation. The hDMC was cultured from human dura mater tissue, and the studies were performed with hDMC after co-culturing with macrophage like THP-1 cells (Mϕ). The adhesion of co-cultured hDMC through collagen I increased 6.4-fold and through collagen IV increased 5.0-fold compared with the adhesion of naïve cells (p < 0.001). Integrin subtype α₂ β₁ expression was increased 6.3-fold (p < 0.001) and α₁ expression was decreased 2.0-fold (p < 0.001) in the co-cultured cells compared with the naïve cells. Co-culturing induced significant increases in MMP-1 (13.9-fold, p < 0.01), MMP-3 (7.6-fold, p < 0.01), and VEGF (VEGF: 3.8-fold, p < 0.05) expression and decreases in MMP-9 (0.1-fold, p < 0.01) compared with the sum of naïve hDMC and Mϕ values. Increased hDMC adhesion under inflammatory conditions is caused by an increased cellular affinity for collagen I and IV mediated by increased hDMC levels of integrin subtype α₂ β₁ and environmental MMP-1, -3 and decreased MMP-9. Selective integrin subtype α₂ β₁ inhibition assay showed 37.8% and 35.7% reduction in adhesion of co-cultured hDMC to collagen I (p < 0.001) and IV (p = 0.057), respectively. The present study provides insight into the pathological conditions related to dura mater adhesion in inflammation. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 9999:1-11, 2019.

Antifibrotic Effect of Boric Acid in Rats with Epidural Fibrosis

BACKGROUND

Epidural fibrosis is a major problem after spine surgery, with some patients having recurrent symptoms secondary to excessive formation of scar tissue resulting in neurologic compression. We used a rat laminectomy model to determine if topical application of boric acid could be helpful in the prevention of epidural fibrosis.

METHODS

Rats were randomly assigned to 2 control and 2 experimental groups (n = 8 for each group). The negative control group received no surgery, and the positive control group underwent laminectomy only. Experimental groups were classified according to the study agents applied onto the dura mater after laminectomy at the L3 level: 2.5% boric acid solution and 5% boric acid solution. The extent of epidural fibrosis was assessed 4 weeks later macroscopically and histopathologically.

RESULTS

Boric acid reduced epidural fibrosis in rats after laminectomy. The effect of 5% boric acid solution was more pronounced (P < 0.05) compared with the 2.5% solution.

CONCLUSIONS

The antifibrotic effect of boric acid solution for the prevention of epidural fibrosis suggests that boric acid should be further evaluated in future studies for the prevention of epidural fibrosis.

Effect of statins on experimental postoperative adhesion: a systematic review and meta-analysis

Adhesion is a significant concern after surgery. Many researchers studied the anti-adhesive effect of statin, of which results were inconsistent. Thus, we purposed to perform a systematic review and meta-analysis to evaluate the effect of statins on postoperative adhesion in an experimental study. A comprehensive search was conducted using MEDLINE, EMBASE, and Google Scholar to identify animal studies that investigated the postoperative anti-adhesive effect of statins applied at the surgical area. Primary outcome measure was gross adhesion score. Secondary outcomes included microscopic adhesion score and tissue plasminogen activator (t-PA) activity. Totally, 298 rats from 9 animal studies (172 rats received statin therapy and 126 rats received placebo or no treatment) were included in the final analysis. The combined results showed that gross and microscopic adhesion scores were significantly lower in the statin group in comparison to the control group (standardized mean difference [SMD] = 1.65, 95% confidence interval [CI]: 1.02 to 2.28, P_chi² < 0.001, I² = 77.9%; SMD = 1.90, 95% CI: 1.10 to 2.79, P_chi² < 0.001, I² = 84.5%, respectively). However, there was no evidence of a difference in t-PA activity (SMD = -3.43, 95% CI: -7.95 to 1.09, P_chi² < 0.001, I² = 95.5%). In conclusion, statins were effective in preventing postoperative adhesion, as assessed based on gross and microscopic adhesion scores in rats.

Mechanical barriers and transforming growth factor beta inhibitor on epidural fibrosis in a rabbit laminectomy model

Background

TGF-β has been described as a mediator of fibrosis and scarring. Several studies achieved reduction in experimental scarring through the inhibition of TGF-β. Fibroblasts have been defined as the cell population originating fibrosis, blocking fibroblast invasion may impair epidural fibrosis appearance. For this purpose, biocompatible materials used as mechanical barriers and a TGF-β inhibitor peptide were evaluated in the reduction of epidural fibrosis.

Methods

A L6 laminectomy was performed in 40 New Zealand white rabbits. Divided into four groups, each rabbit was assigned to receive either collagen sponge scaffold (CS group), gelatin-based gel (GCP group), P144® (iTGFβ group), or left untreated (control group). Four weeks after surgery, cell density, collagen content, and new bone formation of the scar area were determined by histomorphometry. Two experienced pathologists scored dura mater adhesion, scar density, and inflammatory infiltrate in a blinded manner.

Results

In all groups, laminectomy site was filled with fibrous tissue and the dura mater presented adhesions. Only GCP group presented a significant reduction in collagen content and scar density.

Conclusion

GCP treatment reduces epidural fibrosis although did not prevent dura mater adhesion completely.

Electronic supplementary material

The online version of this article (10.1186/s13018-018-0781-6) contains supplementary material, which is available to authorized users.

Evaluation of topical Dexmedetomidine administration in postlaminectomy epidural fibrosis rat model

Epidural fibrosis is a challenging topic in spinal surgery. Numerous clinical and experimental studies have been focused on this issue to clarify problems faced in spinal procedures for the patient as well as the surgeon and find out new methodologies. Dense cytokines and growth factors which are released from inflammatory cells have been suggested to play a major role in the inception and progression of fibrosis. One of the most investigated and important actor in epidural fibrosis is assumed to be the transforming growth factor-1β (TGF-1β) formation. Studies showed that Dexmedetomidine (DEX) downregulates TGF-β pathway with its anti-inflammatory and antioxidant effects. From this point of view, for the first time in the literature we try to observe if there will be an effect of topical DEX administration over epidural fibrosis in a rat model. We hypothesized that DEX might have preventive effects on epidural fibrosis via anti-inflammatory and antioxidant effects. Twenty-four adult male Wistar albino rats were randomly assigned to three groups (Topical DEX, Spongostan, Laminectomy). A total laminectomy was performed at the L3-L5 level and then the ligamentum flavum and epidural fat tissue were cleared away from the surgical site. Histopathological assessment was performed postoperatively after 4 weeks. Our study revealed that topical DEX administration may have effects on reducing epidural fibrosis. Topical DEX administration may be helpful in preventing epidural fibrosis after laminectomy in rats through multiple anti-inflammatory and antioxidant mechanisms as well as through TGF -1β pathway.

Update on biomaterials for prevention of epidural adhesion after lumbar laminectomy

Lumbar laminectomy often results in failed back surgery syndrome. Most scholars support the three-dimensional theory of adhesion: Fibrosis surrounding the epidural tissues is based on the injured sacrospinalis behind, fibrous rings and posterior longitudinal ligaments. Approaches including using the minimally invasive technique, drugs, biomaterial and nonbiomaterial barriers to prevent the postoperative epidural adhesion were intensively investigated. Nevertheless, the results are far from satisfactory. Our review is based on various implant biomaterials that are used in clinical applications or are under study. We show the advantages and disadvantages of each method. The summary will help us to figure out ideas towards new techniques. The translational potential of this article: This review summarises recent biomaterials-related clinical and basic research that focuses on prevention of epidural adhesion after lumbar laminectomy. We also propose a novel possible translational method where a soft scaffold acts as a physical barrier in the early stage, engineered adipose tissue acts as a biobarrier in the later stage in the application of biomaterials and adipose-derived mesenchymal stem cells are used for prevention of epidural adhesion.

Intraperitoneal administration of rosuvastatin prevents postoperative peritoneal adhesions by decreasing the release of tumor necrosis factor

Objectives

The purpose of this experimental study was to demonstrate the reduction of peritoneal adhesions formation in rats after intraperitoneal administration of rosuvastatin, due to its anti-inflammatory effect.

Method

Peritoneal adhesions were induced in 120 Wistar-Bratislava rats divided into 4 groups (n=30), using a parietal and visceral (cecal) abrasion model. Group I was designated as control group; in group II, a saline solution was administered intraperitoneally; in groups III and IV, a single dose of rosuvastatin solution, 10 mg/kg and 5 mg/kg respectively, was injected intraperitoneally. The serum values of tumor necrosis factor (TNF-α) and interleukin-1 (IL-1α) were determined on day 1 and day 7 postoperatively (ELISA). Macroscopic assessment of the peritoneal adhesions was conducted on day 14.

Results

Rosuvastatin therapy induced a significant decrease of tumor necrosis factor serum levels in groups III and IV, on day 1 and day 7 (p<0.01). Intraperitoneal administration of rosuvastatin correlated with a decrease of mean interleukin-1α levels on postoperative day 1 in groups III (p=0.0013) and IV (p=0.00011), but not on day 7, where the differences were no longer statistically significant (p=0.8) The reduction of postoperative peritoneal adhesions in the experimental rat model is supported by the anti-inflammatory effect of rosuvastatin, mediated mainly by the tumor necrosis factor.

Conclusions

Rosuvastatin prevents the formation of postoperative peritoneal adhesions in rats. This effect may be linked to the inhibition of proinflammatory cytokines release in the early stages of adhesions formation. The present study suggests that rosuvastatin may be an efficient pharmacological agent in the prevention of postoperative peritoneal adhesions development, and requires further studies as it has a promising application value.

Diadenosine tetraphosphate (Ap4A) inhibits ATP-induced excitotoxicity: a neuroprotective strategy for traumatic spinal cord injury treatment

Reducing cell death during the secondary injury is a major priority in the development of a cure for traumatic spinal cord injury (SCI). One of the earliest processes that follow SCI is the excitotoxicity resulting from the massive release of excitotoxicity mediators, including ATP, which induce an excessive and/or prolonged activation of their receptors and a deregulation of the calcium homeostasis. Diadenosine tetraphosphate (Ap4A) is an endogenous purinergic agonist, present in both extracellular and intracellular fluids, with promising cytoprotective effects in different diseases including neurodegenerative processes. In a search for efficient neuroprotective strategies for SCI, we have tested the capability of Ap4A to reduce the excitotoxic death mediated by the ATP-induced deregulation of calcium homeostasis and its consequences on tissue preservation and functional recovery in a mouse model of moderate contusive SCI. Our analyses with the murine neural cell line Neuro2a demonstrate that treatment with Ap4A reduces ATP-dependent excitotoxic death by both lowering the intracellular calcium response and decreasing the expression of specific purinergic receptors. Follow-up analyses in a mouse model of contusive SCI showed that acute administration of Ap4A following SCI reduces tissue damage and improves motor function recovery. These results suggest that Ap4A cytoprotection results from a decrease of the purinergic tone preventing the effects of a massive release of ATP after SCI, probably together with a direct induction of anti-apoptotic and pro-survival pathways via activation of P2Y2 proposed in previous studies. In conclusion, Ap4A may be a good candidate for an SCI therapy, particularly to reduce excitotoxicity in combination with other modulators and/or inhibitors of the excitotoxic process that are being tested.

Is the use of hemostatic matrix (Floseal) and alkylene oxide copolymer (Ostene) safe in spinal laminectomies? Peridural fibrosis assessment

Objective

Failed Back Syndrome (FBS) is unacceptable relief of pain or recurrence of symptoms in patients after spinal surgery, such as laminectomy. One possible cause of FBS is peridural fibrosis (PF). PF is the overproduction of scar tissue adjacent to the dura mater. Bleeding can cause PF after laminectomy. Ostene is an alkylene oxide copolymer material used to stop bleeding from bony surfaces. Floseal is a gelatin thrombin matrix sealant used to assist fibrin formation and to promote coagulation.

Methods

Total of 32 female Sprague–Dawley rats were evenly allotted to 4 experimental groups: laminectomy only, laminectomy + Ostene (Baxter International, Inc., Deerfield, IL, USA), laminectomy + Floseal (Baxter International, Inc., Deerfield, IL, USA), and laminectomy + Adcon-L (aap Implantate AG, Berlin, Germany). After performing total laminectomy, agents were placed over dura mater. Spinal column of test subjects was harvested 6 weeks after laminectomy. Histopathological examination of samples was based on Masson's trichrome and hematoxylin and eosin staining. PF observed in the groups was graded using system previously described by He et al. Statistically significant p value was defined as p < 0.005.

Results

Present study revealed that Adcon-L, Ostene, and Floseal groups had reduced PF compared with laminectomy only group (p = 0.001). Comparison of Ostene and Floseal groups with Adcon-L group yielded no significant difference.

Conclusion

Reoperation as result of FBS has greater risk and often has poor outcome; surgeons must take precautions to avoid FBS, such as careful selection of appropriate patient and operation technique. Ostene and Floseal may be applied and left in the operation field safely during laminectomy to reduce occurrence of PF after procedure.

Salvianolic acid B reduced the formation of epidural fibrosis in an experimental rat model

Background

Salvianolic acid B (Sal B) was newly reported to be able to attenuate fibrosis in the animal model. The aim of the present study was to investigate the effect of the intragastric application of Sal B on the prevention of epidural fibrosis (EF).

Methods

Forty healthy adult male Wistar rats were divided into four treatment groups (n = 10 per group): (1) 10 mg/kg Sal B, (2) 30 mg/kg Sal B, (3) 50 mg/kg Sal B and (4) Saline (vehicle treatment, control group). All animals underwent a laminectomy at the lumbar 1–2 (L 1–2) level. After intragastric treatment, all rats were sacrificed at post-operative week 8. The extent of the epidural scar, the regeneration of the vasculature and the expression levels of vascular endothelial growth factor (VEGF) were analysed.

Results

The animals’ recovery was uneventful during the experimental period. The extent of the epidural scar, the regeneration of the vasculature and the expression levels of VEGF suggested better outcomes in the Sal B-treated groups. Sal B exerted the ability to prevent the formation of an epidural scar and vascularization at the laminectomy sites. The effects of Sal B were dose-dependent, with the 50 mg/kg Sal B group showing the best outcomes compared with the other groups.

Conclusions

Post-operative intragastric application of Sal B can prevent the formation of epidural scarring. Sal B exerted these effects in a dose-dependent manner, and 50 mg/kg dose was shown to be the best effect in the present study. The results of this study reveal that Sal B could be a potential therapy for EF and valuable for further research.

The Effects of Rifampin, Povidone-Iodine and Hydrogen Peroxide on the Formation of Epidural Fibrosis in the Experimental Epidural Fibrosis Model

The aim of the study was to determine the effect of direct application of rifampin, povidone-iodine, and hydrogen peroxide on the formation of epidural fibrosis in rats. Forty-eight adult male Wistar albino rats were equally and randomly divided into four groups (laminectomy, topical rifampin, topical povidone-iodine, and topical hydrogen peroxide). Laminectomy was performed at the T12 level in all rats. Four weeks later, the extent of epidural fibrosis was assessed both macroscopically and histopathologically. ANOVA test was used for the evaluation of dural thickness. Kruskal-Wallis test was used for the pathology and macroscopic evaluation. Chi-square test was used for evaluation of the arachnoid involvement. p value <0.05 was accepted as statistically significant. Our data revealed that topical application of both povidone-iodine and hydrogen peroxide were effective in reducing epidural fibrosis formation. The results of our study provide the experimental evidence of the preventive effects of topical application of povidone-iodine and hydrogen peroxide over epidural fibrosis.

The Topical Application of Rosuvastatin in Preventing Knee Intra-Articular Adhesion in Rats

BACKGROUND Intra-articular adhesion is one of the common complications of post knee surgery and injury. The formation of joint adhesion can lead to serious dysfunction. Rosuvastatin (ROS) is a new 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor, with multiple biological effects. In our study, the object was to evaluate the effectiveness of ROS in the prevention of post-operative knee adhesion in rats. MATERIAL AND METHODS Femoral condyle exposing surgery was performed on 45 healthy Sprague Dawley rats. Gelatin sponges soaked with 20 mg/kg of ROS, 10 mg/kg of ROS, or saline were used to cover the surgical site. The post-operative knee joints were fixed in a flexed position with micro Kirschner wires for four weeks. ROS effectiveness for treating intra-articular adhesion was determined with visual score evaluation, hydroxyproline content, histological analyses, immunohistochemistry, and inflammatory and vascular endothelial growth factors expression. RESULTS The animals' recovery was stable after surgery. The hydroxyproline content, visual score, and inflammatory vascular growth factors expression levels suggested that, compared with the control group, the ROS treatment groups showed better outcomes. ROS prevented joint adhesion formation, collagen deposition, and vascularization at the surgical site, and also inhibited inflammatory activity post-operatively. Compared with the 10 mg/kg ROS group, the 20 mg/kg ROS group showed significantly better outcomes. CONCLUSIONS The local application of ROS reduced intra-articular adhesion formation, collagen deposition, and vascularization at the surgical site, and inhibited inflammatory activity post-operatively. These results suggested optimal concentration of ROS to be 20 mg/kg.

Effects of hemostatic polysaccharide agent on epidural fibrosis formation after lumbar laminectomy in rats

BACKGROUND CONTEXT

Epidural fibrosis is a common adverse outcome of spinal surgery that can compress the dural sac and nerve root. Local hemostatic agents have many indications in numerous types of spinal surgery. As these agents may behave as foreign bodies, inducing inflammation and delaying regeneration, they could enhance the risk of epidural fibrosis.

PURPOSE

We evaluated the effects of hemostatic polysaccharide on epidural fibrosis development in laminectomized rats.

STUDY DESIGN

This is a randomized controlled trial.

OUTCOME MEASURES

One month after surgery, tissues were histopathologically examined. Spinal tissue surrounding the laminectomy site was cut with a microtome and stained with hematoxylin and eosin and Masson trichrome. Slides were evaluated by a pathologist in a blinded fashion. The extent of epidural fibrosis, fibroblast cell density, cartilage, and bone regeneration was evaluated.

METHODS

Rats were randomly assigned to receive sham surgery, laminectomy, or laminectomy with hemostatic polysaccharide (seven rats per group). Sham surgery that consisted of a skin incision was performed without laminectomy. Laminectomy was performed at the L1 and L2 vertebrae. In the experimental group, the polysaccharide hemostatic material, HaemoCer was placed in the laminectomy area.

RESULTS

The proportion of rats with epidural fibrosis in laminectomized mice (both with and without hemostatic material) was higher than in sham-operated rats (p<.01). There was no difference in fibrosis between the two groups of laminectomized rats (p>.05).

CONCLUSIONS

Our study indicates that hemostatic polysaccharide does not enhance epidural fibrosis following laminectomy in rodents, suggesting that absorbable polysaccharides may be appropriate for use in hemostasis during spinal surgery.