Effect of topical application of mitomycin-C on wound healing in a postlaminectomy rat model: an experimental study

Collagen and chitosan-based biogenic sprayable gel of silver nanoparticle for advanced wound care

Silver nanoparticles have gained significant attention recently due to their unique antibacterial properties, making them promising candidates for wound care applications. This study proposes a novel approach for advanced wound care using a silver nanoparticle-impregnated biogenic spray hydrogel supplemented with collagen and chitosan. Silver nanoparticles were incorporated into the hydrogel (optimized by a QbD approach) to impart antimicrobial activity, crucial for combating wound infections and promoting faster healing. The study assessed the physical and chemical properties of the biogenic hydrogel, including its viscosity, pH, and nanoparticle dispersion characteristics. In vitro, antimicrobial efficacy against common wound pathogens and in vivo studies using chronic wound models in small animals portrayed the immense potential of the developed biogenic hydrogel in effectively reducing the bacterial load of broad-spectrum pathogens. The hydrogel exhibited excellent biocompatibility, supporting cell proliferation and tissue repair without toxic effects. It accelerated wound healing, improved collagen deposition, and enhanced tissue regeneration in the tested animals by reducing proinflammatory cytokines, ROS, and NF-kb levels. Overall, this innovative silver nanoparticle-impregnated biogenic spray hydrogel of collagen and chitosan presents a uniform spray pattern that proved efficient, showing a promising solution for advanced wound care. Its biocompatibility, safety, anti-inflammatory, antimicrobial efficacy, and wound healing properties hold great potential for improving the management of complex wounds, opening new avenues in wound care and regenerative medicine.

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.

Reconstruction of Epidural Fat to Prevent Epidural Fibrosis After Laminectomy in Rabbits

Background: Laminectomy can effectively decompress the spinal cord and expand the vertebral canal. However, the fibrosis that appears may cause adherence and recompression of the spinal cord or/and nerve root, which may cause failed back syndrome (FBS) and make the reexposure process more difficult. Reconstruction of the epidural fat may be an ideal method to achieve satisfactory results. Methods: Thirty-six New Zealand rabbits were randomly divided into three groups: control, extracellular matrix (ECM), and ECM+aMSCs groups. Saline, ECM gel, and ECM+aMSC complex were placed, respectively, at the fifth lumbar vertebrate of the rabbits. Epidural fat and fibrosis formation were detected by magnetic resonance imaging (MRI) and histologically at the 4th, 8th, and 12th weeks. Quantitative RT-PCR was used to detect the expression of interleukin 6 (IL-6) and transforming growth factor β (TGF-β). Results: MRI and Oil Red O staining revealed epidural fat formation at the 12th week in the ECM+aMSCs group. Hematoxylin and eosin staining showed that the numbers of fibroblasts in the ECM gel and ECM+aMSCs groups were less than the control group at the 4th and 8th weeks (p < 0.05). Masson's trichrome staining showed that the proportion of collagen fibers in the ECM gel and ECM+aMSCs group was lower than the control group (p < 0.05). Quantitative RT-PCR showed the expressions of TGF-β and IL-6 were lower in the ECM gel and ECM+aMSCs group than those in the control group (p < 0.05) at the 4th week, but higher at the 8th week. Conclusion: We successfully reconstructed the epidural fat with ECM gel and aMSC complex; additionally, IL-6 and TGF-β cytokines were lower at early stage after laminectomy.

Intralesional injection of mitomycin C following internal urethrotomy of de novo bulbar urethral stricture:New experience using a novel adjustable-tip needle

Objectives: To assess the efficacy of intralesional injection of mitomycin C (MMC), using a novel adjustable-tip needle, following visual internal urethrotomy (VIU) in reducing the recurrence of de novo bulbar urethral stricture disease (USD).

Patients and methods: Using closed envelopes, 50 patients diagnosed with bulbar USD of <2 cm were randomised to undergo either VIU with MMC injections (Group-A) or VIU alone (Group-B). The urethrotomy was performed under direct vision using a cold-knife and incisions were made at the 12-, 4-, and 8-o’clock positions followed by intralesional injection of 10 mL MMC (0.4 mg/mL) using a novel depth-adjusting needle. All patients were objectively evaluated pre- and postoperatively at 3, 6, and 9 months using uroflowmetry (maximum urinary flow rate), post-void residual urine volume, and retrograde urethrography.

Results: Of all 50 patients; five missed follow-up (four in Group-A, one in Group-B), hence 45 cases were available for analysis (21 in Group-A and 24 in Group-B). The mean (SD) age of patients was 34.33 (7.2) and 37.7 (10.2) years in Group-A and Group-B, respectively (P = 0.22). The depth-adjusting needle was easy to use and all injections were successfully completed. In terms of stricture recurrence, there was significant decrease in Group-A (three patients, 14.3%) compared with Group-B; (12 patients, 50%) (P = 0.01). On multivariate Cox regression analysis, the VIU with MMC was found as a sole factor associated with marked decrease in stricture recurrence (hazard ratio 0.23, 95% confidence interval 0.06–0.93; P = 0.04). The Kaplan–Meier survival curve for recurrence-free survival showed a statistically significant difference between both groups (85.7% vs 50.0%; chi-squared = 7.079, P = 0.008).

Conclusion: The use of a novel depth-adjusting needle was easily applied and MMC injection after VIU resulted in a significantly lower recurrence of de novo bulbar USD.

Abbreviations : MMC: mitomycin C; PVR: post-voiding residual urine; Q_max: maximum urinary flow rate; RFS: recurrence-free survival; RUG: retrograde urethrography; USD: urethral stricture disease; VIU: visual internal urethrotomy

Treatment with Hyaluronic Acid and Collagen-Polyvinylpyrrolidone Improves Extracellular Matrix Assembly for Scarring after Tracheal Resection

Treatment of tracheal stenosis is occasionally performed in combination with wound healing modulators to manipulate new extracellular matrix (ECM) formation and prevent fibrosis. Hyaluronic acid (HA) and collagen-polyvinylpyrrolidone (collagen-PVP) decrease fibrosis in experimental tracheal healing. However, they have not been used clinically as their effect on ECM components, which modify tracheal scarring, has not been described. Objective. To evaluate the effect of the application of HA, collagen-PVP, a mixture of HA and collagen-PVP (HA+collagen-PVP), and mitomycin C on the expression of decorin, matrix metalloproteinase 1 (MMP1), and MMP9, as well as the type of collagen and deposits formed in the scar after resection and end-to-end anastomosis (REEA) of the cervical trachea using an experimental model. Materials and Methods. Thirty dogs underwent REEA of the cervical trachea and were treated with different wound healing modulators: group I (n = 6), control; group II (n = 6), HA; group III (n = 6), collagen-PVP; group IV (n = 6), HA+collagen-PVP; and group V (n = 6), mitomycin C. The dogs were evaluated clinically and endoscopically for 4 weeks. Subsequently, macroscopic and microscopic changes, expression of ECM proteins, and collagen deposition in tracheal scars were analysed. Results. Groups II, III, and IV showed reduced endoscopic, macroscopic, and microscopic inflammation, improved neovascularization, high decorin expression (p < 0.01, analysis of variance (ANOVA)), and moderate expression of MMP1 (p < 0.003, ANOVA) and type I and III collagen (p < 0.05, Kruskal–Wallis). Groups IV and V developed fewer collagen deposits (p < 0.001, ANOVA). Conclusion. Treatment with HA and collagen-PVP improved post-REEA healing by increasing neovascularization, stimulating the expression of decorin, and regulating the expression of MMP1, as well as type I and III collagen and their deposition.

Efficacy of mitomycin-C on anterior urethral stricture after internal urethrotomy: A systematic review and meta-analysis

Background and Aim Mitomycin-C is a potent agent that plays an important role in tissue healing and scar formation. This study aims to investigate the efficacy of Mitomycin-C in treating anterior urethral stricture after internal urethrotomy. Methods Studies evaluating efficacy of mitomycin-c for anterior urethral stricture post urethrotomy were searched using Pubmed, Scopus, Sciencedirect, MEDLINE, and Cochrane Reviews as directory databases. The search was done in March 15th 2020. Terms being used in the searching process were "mitomycin-c" or "mitomycin", "urethral stricture", "urethral stenosis", "internal urethrotomy", "optical urethrotomy" and its synonyms. Every study with the design of retrospective or prospective clinical study being done in human subject was included. Study appraisal conducted in accordance to Oxford University Center for Evidence-Based Medicine. The conclusion of each study was summarized and the calculation of random effects from every study was conducted in meta-analysis. Random effects model is chosen because small number of studies and quite different. Results Three studies involving 311patients were included in this review, all of them reported less recurrence of in patients treated with mitomycin-c post urethrotomy (p<0.001). Risk ratio of all studies was 0.41 with 95% confidence interval (0.25-0.68).   Conclusion Mitomycin-C has the potential of efficacy in treating anterior urethral stricture post internal urethrotomy. Relatively few numbers of studies may impact in the strength of this review and further studies need to be done.

Efficacy of mitomycin-C on anterior urethral stricture after internal urethrotomy: A systematic review and meta-analysis

Background: Mitomycin-C is an agent that plays an important role in the tissue healing process and scar formation. This study aims to investigate the efficacy of mitomycin-C in treating anterior urethral stricture following internal urethrotomy. Methods: Studies evaluating the efficacy of mitomycin-c for anterior urethral stricture post urethrotomy were searched using PubMed, Scopus, ScienceDirect, EBSCOHost, Cochrane Reviews, and OVID as directory databases. Terms used in the searching process were "mitomycin-c" or "mitomycin", "urethral stricture", "urethral stenosis", "internal urethrotomy", "optical urethrotomy" and its synonyms. Every randomized controlled trial study conducted in human subjects was included. Study appraisals were conducted in accordance with Oxford University Center for Evidence-Based Medicine guidelines. The conclusion of each study was summarized and the calculation of fixed effect from every study was conducted in meta-analysis. Results: Included in this study were three studies involving 231 patients. All of them reported less recurrence of in patients treated with mitomycin-c post urethrotomy (p<0.001). The fixed risk ratio of all studies was 0.32 with 95% confidence interval (0.19-0.54). All studies also reported less stricture length after treatment with mitomycin-c, but there were not statistical differences between with or without treatment group. Conclusion: Mitomycin-C has efficacy in treating anterior urethral stricture after internal urethrotomy. However, the inclusion of relatively few studies may affect the strength of this review and further studies need to be done.

Efficacy of mitomycin-C on anterior urethral stricture after internal urethrotomy: A systematic review and meta-analysis

Background and Aim Mitomycin-C is a potent agent that plays an important role in tissue healing and scar formation. This study aims to investigate the efficacy of Mitomycin-C in treating anterior urethral stricture after internal urethrotomy. Methods Studies evaluating efficacy of mitomycin-c for anterior urethral stricture post urethrotomy were searched using Pubmed, Scopus, Sciencedirect, MEDLINE, and Cochrane Reviews as directory databases. The search was done in March 15th 2020. Terms being used in the searching process were "mitomycin-c" or "mitomycin", "urethral stricture", "urethral stenosis", "internal urethrotomy", "optical urethrotomy" and its synonyms. Every study with the design of retrospective or prospective clinical study being done in human subject was included. Study appraisal conducted in accordance to Oxford University Center for Evidence-Based Medicine. The conclusion of each study was summarized and the calculation of random effect from every study was conducted in meta-analysis. Random effect model is chosen because small number of studies and quite different. Results Three studies involving 311patients were included in this review, all of them reported less recurrence of in patients treated with mitomycin-c post urethrotomy (p<0.001). Risk ratio of all studies was 0.41 with 95% confidence interval (0.25-0.68).   Conclusion Mitomycin-C has the potential of efficacy in treating anterior urethral stricture post internal urethrotomy. Relatively few numbers of studies may impact in the strength of this review and further studies need to be done.

Artesunate inhibits fibroblasts proliferation and reduces surgery-induced epidural fibrosis via the autophagy-mediated p53/p21waf1/cip1 pathway

Fibroblast proliferation is considered to be a major cause in the process of epidural fibrosis formation. Autophagy is a tightly-regulated catabolic process in charge of degrading intracellular components. Although autophagy has been associated with fibrosis of different tissues, the effect of autophagy on epidural fibrosis is still unknown. The aim of this study was to investigate the function and mechanism of autophagy induced by Artesunate (ART), a classical antimalarial agent extracted from the Chinese medicinal herb. In vitro, the effect of ART on inducing fibroblast autophagy was evaluated via LC3 immunofluorescent staining, Transmission Electron Microscopy (TEM) and western blotting analysis. Moreover, the effect of ART on inhibiting fibroblast proliferation was investigated by CCK-8 assay, EdU incorporation assay, flow cytometry and western blotting analysis. Results indicated that ART could induce autophagy and inhibit proliferation in fibroblasts. The inhibitory effect of ART on fibroblast proliferation was associated with the upregulation of p53 and p21^waf1/cip1 proteins. Intriguingly, 3-MA, a classical autophagy inhibitor, attenuated ART-induced p53/p21^waf1/cip1 pathway activation and fibroblast proliferation inhibition. In vivo, the effect of ART on reducing epidural fibrosis was detected by histological macroscopic assessment, hydroxyproline content analysis, histological and immunohistochemical staining. The results revealed that ART had significant suppressive effects on epidural fibrosis following laminectomy in rats. In conclusion, this research demonstrated that ART could inhibit fibroblast proliferation and reduce epidural fibrosis formation after laminectomy, and the potential mechanism might through autophagy cascade-mediated p53/p21^waf1/cip1 pathway. It might provide a novel reagent for reducing epidural fibrosis after spinal laminectomy surgery.

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.

Effect of Mitomycin - C and Triamcinolone on Preventing Urethral Strictures

Urethral stricture is a common disease with high recurrence rate. Several manipulations were defined to prevent the recurrence but the results were disappointing. This study aimed to evaluate the efficacy of triamcinolone and mitomycin-C on urethral stricture formation and their effect on inhibition of urethral fibrosis. A total of 24 New Zealand rabbits were divided into 3 groups. Urethras of rabbits were traumatized with pediatric resectoscope. Resection area was irrigated with 10mL saline, swapped with a cotton wool soaked with 0.5mg/mL MMC and injected by 40mg triamcinolone in groups 1, 2 and 3 respectively. Retrograde urethrogram was performed at 28^th day of procedure and the urethra was removed for histopathologic evaluation. There were significant differences in urethral diameters and in lumen reduction rate between the control and study groups (p<0.001). Compared to control group, all treatment groups showed mild fibrosis, less collagen bundle irregularity, and lower numbers of fibroblasts (p=0.003). The Tunnel assay showed that the number of apoptotic cells in the submucosal connective tissue was quantitatively higher in control groups (p=0.034). In the view of efficacy and safety, MMC and triamcinolone have the potential to replace the use of stents, clean intermittent catheterization, or long term catheters following internal urethrotomy. There were no statistically significant differences between two agents in terms of preventing urethral stricture formation in the present study. Mitomycin C and triamcinolone decreased the recurrence rates of urethral stricture.

Effects of Pirfenidone and Collagen-Polyvinylpyrrolidone on Macroscopic and Microscopic Changes, TGF-β1 Expression, and Collagen Deposition in an Experimental Model of Tracheal Wound Healing

Tracheal stenosis (TS) is a fibrosis originated by prolonged inflammation and increased transforming growth factor beta 1 (TGF-β1) expression and collagen deposition (CD) in the tracheal wound. Several wound-healing modulators (WHMs) have been used to modulate the tracheal healing process and prevent TS, but they have failed, justifying the need to evaluate alternative WHM. The pirfenidone (PFD) and collagen-polyvinylpyrrolidone (Collagen-PVP) decrease inflammation and fibrosis. This study assessed the effect of PFD administration and Collagen-PVP topical application on macroscopic and microscopic changes, TGF-β1 expression, and CD in an experimental model of tracheal wound healing. Forty Wistar rats underwent cervical tracheoplasty, were divided into 4 groups (n = 10), and were treated with different WHM: group I, saline solution (SS); group II, Collagen-PVP; group III, mitomycin C (MMC); and group IV, 40 mg/kg PFD. Four weeks after surgery, the macroscopic and microscopic changes, in situ TGF-β1 expression, and CD in posttracheoplasty scars were evaluated. The animals treated with Collagen-PVP and PFD developed less inflammation and fibrosis than animals in the other study groups (p < 0.05, Kruskal-Wallis) and, moreover, showed lower TGF-β1 expression and CD than animals in group I (p < 0.05, ANOVA and Tukey's test). In conclusion, PFD and Collagen-PVP decrease inflammation, fibrosis, TGFβ-1 expression, and CD in the posttracheoplasty rats' scar.

Pentoxifylline Inhibits Epidural Fibrosis in Post-Laminectomy Rats

BACKGROUND

The aim of this experimental study was to investigate the effectiveness of intramuscular pentoxifylline in the prevention of postoperative fibrosis.

MATERIAL/METHODS

We divided 16 adult Wistar albino rats into 2 equal groups: treatment and control. Both groups underwent L1 vertebral total laminectomy to expose the dura. The intramuscular treatment group received pentoxifylline. Four weeks later, epidural fibrosis was studied in both groups using electron microscopy, light microscopy, histology, biochemistry, and macroscopy.

RESULTS

The evaluation of epidural fibrosis in the 2 groups according to macroscopic (p<0.01) assessment and light microscopy revealed that epidural scar tissue formation was lower in the treatment group compared to the control group (p<0.001) and the number of fibroblasts was also decreased significantly in the pentoxifylline-treated group (p<0.05). More immature fibers were demonstrated in the treatment group by electron microscopy in comparison with the control group. In biochemical analysis, a statistically significant decrease was detected in hydroxyproline, which indicates fibrosis and myeloperoxidase activity, and shows an inflammatory response (P<0.001).

CONCLUSIONS

Systemic pentoxifylline application prevents postoperative epidural fibrosis and adhesions with various mechanisms. Our study is the first to present evidence of experimental epidural fibrosis prevention with pentoxifylline.

The effects of ankaferd blood stopper and microporous polysaccharide hemospheres on epidural fibrosis in rat laminectomy model

PURPOSE

To investigate whether topically administered hemostatic agents ankaferd blood stopper and microporous polysaccharide hemospheres can decrease epidural fibrosis after laminectomy in rats.

METHODS

Eighteen adult male Sprague-Dawley rats were equally and randomly divided into three groups. In the treatment groups, ankaferd blood stopper and microporous polysaccharide hemospheres topically administrated upon duramater surface after laminectomy. Fibroblast count, epidural fibrosis and arachnoidal involvement were evaluated and graded histopathologically.

RESULTS

Our data revealed that the count of fibroblasts, the grading of epidural fibrosis and arachnoideal involvement in the rats treated with microporous polysaccharide hemospheres were significantly less than the control group. Although the arachnoideal involvement in ankaferd blood stopper group were significantly less than the control group, there were no statistical differences when comparing the grading of epidural fibrosis and the fibroblasts count between the treatment groups and the control group.

CONCLUSION

The ankaferd blood stopper and microporous polysaccharide hemospheres reduced epidural fibrosis and arachnoideal involvement after laminectomy in rats.

Postoperative Pain after Endodontic Treatment of Asymptomatic Teeth Using Rotary Instruments: A Randomized Clinical Trial

INTRODUCTION

The aim of the present study was to compare the effect of two different rotary instruments on postoperative pain in teeth with asymptomatic irreversible pulpitis.

METHODS AND MATERIALS

A total of 78 mandibular first and second molars were divided into two groups (n=39) and their root canal preparation was carried out with either RaCe or ProTaper rotary instruments. All the subjects underwent one-visit root canal treatment and the severity of postoperative pain was evaluated using visual analog scale (VAS) at 4-, 12-, 24-, 48- and 72-h and 1-week intervals. In addition, the need for taking analgesics was recorded. Data were analyzed with the repeated-measures ANOVA and the Mann-Whitney U test was used for two-by-two comparison. Statistical significance was set at 0.05.

RESULTS

Comparison of mean pain severity between the two groups at various postoperative intervals did not reveal any significant differences (P=0.10). The difference in amount of analgesics taken by each groups was not statistically significant (P=0.25).

CONCLUSION

There were no significant differences in the postoperative pain reported between the two groups; which indicates the clinical acceptability of both systems.

Effects of rapamycin on reduction of peridural fibrosis: an experimental study

Background

Peridural fibrosis (PF) is a normal complication after lumbar surgery. It is a challenge for both surgeons and patients. Rapamycin (RPM), a novel antibiotic with anti-proliferative and immunosuppressive properties, has been shown to be effective in preventing uncontrolled scar proliferation diseases. The object of the present research was to investigate the effects of RPM on inhibiting PF in vitro and in vivo.

Material/Methods

In vitro, the fibroblasts collected and isolated from the rat tail skin were cultured with/without RPM and cell counting was performed. In vivo, the double-blinded study was conducted in 60 healthy Wistar rats divided randomly into 3 groups: 1) RPM treatment group; 2) Vehicle treatment group; 3) Control group. Rats underwent a L1-L2 level laminectomy with a satisfactory anesthetization. Four weeks post-operatively, the Rydell score, histological analysis, hydroxyproline content, vimentin expressional level, and inflammatory cytokines expressional levels were assessed.

Results

In vitro, RPM showed ability to prevent fibroblast proliferation. In vivo, the laminectomy was well tolerated by all rats, which were killed 4 weeks post-operatively. The Rydell score, histological evaluation, hydroxyproline content, vimentin expression level, and inflammatory activity showed the positive effect of RPM in preventing peridural adhesion, inhibiting fibrotic formation and collagen synthesis, and down-regulating inflammation.

Conclusions

In the present primary study, RPM showed good efficacy in preventing the proliferation of fibroblasts. RPM can prevent rat peridural adhesion through inhibiting collagen synthesis, fibroblasts proliferation, and inflammatory activity.

Study on salvianolic acid B in the reduction of epidural fibrosis in laminectomy rats

Background

Epidural fibrosis (EF) is a common complication after laminectomy. Salvianolic acid B (Sal B) is a major bioactive component of a traditional Chinese medical agent, Salvia miltiorrhiza, which has shown anti-inflammatory, anti-fibrotic and anti-proliferative properties. The object of this study was to investigate the effect of Sal B on the prevention of epidural fibrosis in laminectomy rats.

Methods

A controlled double-blinded study was conducted in sixty healthy adult Wistar rats that underwent laminectomy at the L1-L2 levels. The rats were randomly divided into 3 groups of 20: (1) Sal B treatment group; (2) Vehicle group; (3) Sham group (laminectomy without treatment). All rats were sacrificed 4 weeks post-operatively. The extent of epidural fibrosis, fibroblast proliferation and the expression of vascular endothelial growth factor (VEGF) and inflammatory factors were analyzed.

Results

The recovery of all rats was uneventful. In the laminectomy sites treated with Sal B, the dura mater showed no adhesion. Collagen deposition was significantly lower in the Sal B group than the other two groups. In addition, both fibroblast and inflammatory cell counting in the laminectomy sites treated with Sal B showed better grades than the other two groups. The expression of VEGF and inflammatory factors in operative sites also suggested better results in the Sal B group than the other two groups.

Conclusions

Sal B inhibits fibroblast proliferation, blood vessel regeneration, and inflammatory factor expression. Thus, Sal B is able to prevent epidural scar adhesion in post-laminectomy rats.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2474-15-337) contains supplementary material, which is available to authorized users.

Potential risk of mitomycin C at high concentrations on peripheral nerve structure

Although the local application of mitomycin C may prevent epidural adhesion after laminectomy, mitomycin C can induce neurotoxicity in optic and acoustic nerves at high concentrations. To determine the safe concentration range for mitomycin C, cotton pads soaked with mitomycin C at different concentrations (0.1, 0.3, 0.5, and 0.7 mg/mL) were immediately applied for 5 minutes to the operation area of rats that had undergone laminectomy at L₁. Rat sciatic nerves, instead of dorsal nerves, were used in this study. The results showed that mitomycin C at 0.1-0.5 mg/mL did not damage the structure and function of the sciatic nerve, while at 0.7 mg/mL, mitomycin C significantly reduced the thickness of the sciatic nerve myelin sheath compared with lower concentrations, though no functional change was found. These experimental findings indicate that the local application of mitomycin C at low concentrations is safe to prevent scar adhesion following laminectomy, but that mitomycin C at high concentrations (> 0.7 mg/mL) has potential safety risks to peripheral nerve structures.

An experimental novel study: hyperbaric oxygen treatment on reduction of epidural fibrosis via down-regulation of collagen deposition, IL-6, and TGF-β1

OBJECTIVE

To investigate the effect of hyperbaric oxygen treatment (HBO) on prevention of epidural fibrosis in laminectomy rats.

METHODS

A controlled, double-blinded study was performed in sixty healthy adult Wistar rats, mean weight 250 g. L1-L2 levels laminectomy were performed. Randomly, all rats were divided into three groups, with 20 in each group: (1) short-term HBO treatment group; (2) long-term HBO treatment (LHBO) group; and (3) Sham group (laminectomy without treatment). Four weeks post-operation, all rats were killed. The Rydell classification, hydroxyproline content, vimentin cells density, capillary density, and inflammatory factors expression were evaluated.

RESULTS

The histological evaluation showed less epidural scar adhesions in LHBO group than other two groups. The hydroxyproline content, Rydell score, vimentin cells density, capillary density, and inflammatory factors expression all suggested better results in LHBO group than other two groups.

CONCLUSION

It was concluded that HBO treatment might be beneficial in inhibiting collagen deposition and inflammatory activity and prevent epidural scar adhesion in laminectomy rat and, therefore, shows potential for clinical use.

The role of hybrid chitosan membranes on scarring process following lumbar surgery: post-laminectomy experimental model

OBJECTIVES

Post-operative scarring process on lumbar surgery is object of several studies mainly because of the epidural fibrosis formation. Hybrid chitosan have shown promising effect on fibrosis prevention. The aim of this study was to determine the influence of chitosan-silane membrane on the lumbar surgery scarring process. These membranes have improved mechanical strength which makes them suitable to maintain a predefined shape.

METHODS

A two level lumbar laminectomy was performed in 14 New Zealand male rabbits. Laminectomy sites were randomly selected for biomaterial or control. Chitosan membranes were prepared and care was taken in order to make it adapted to the bone defect dimensions covering the totality of the defect including the bone margins. Histological analysis was performed by haematoxylin/eosin and by Masson's trichrome staining four weeks after laminectomy.

RESULTS

Microscope observations revealed the presence of a well-organized regenerating tissue, integrated in the surrounding vertebral bone tissue with a regular and all-site interface on the chitosan sites, in clear contrast with the presence of a disorganized regenerating tissue with aspects consistent with the persistence of a chronic inflammatory condition, on control sites.

DISCUSSION

The results of this study clearly demonstrated that hybrid chitosan had an organizing effect on post-operative scarring process. The presence of the hybrid chitosan membrane resulted on a well-organized tissue integrated in the surrounding vertebral bone tissue with signs of regenerative bone tissue in continuity with native bone. This can be a major feature on the dynamics of epidural fibrosis formation.

Investigation of efficacy of mitomycin-C, sodium hyaluronate and human amniotic fluid in preventing epidural fibrosis and adhesion using a rat laminectomy model

Study Design

A retrospective study.

Purpose

The aim of this study was to evalute the effects of mitomycin-C, sodium hyaluronate and human amniotic fluid on preventing spinal epidural fibrosis.

Overview of Literature

The role of scar tissue in pain formation is not exactly known, but it is reported that scar tissue causes adhesions between anatomic structures. Intensive fibrotic tissue compresses on anatomic structures and increases the sensitivity of the nerve root for recurrent herniation and lateral spinal stenosis via limiting movements of the root. Also, neuronal atrophy and axonal degeneration occur under scar tissue.

Methods

The study design included 4 groups of rats: group 1 was the control group, groups 2, 3, and 4 receieved antifibrotic agents, mitomycin-C (group 2), sodium hyaluronate (group 3), and human amniotic fluid (group 4). Midline incision for all animals were done on L5 for total laminectomy. Four weeks after the surgery, the rats were sacrificed and specimens were stained with hematoxylin-eosin and photos of the slides were taken for quantitive assesment of the scar tissue.

Results

There was no significant scar tissue in the experimental animals of groups 2, 3, and 4. It was found that there was no significant difference between drug groups, but there was a statistically significant difference between the drug groups and the control group.

Conclusions

This experimental study shows that implantation of mitomycin-C, sodium hyaluronate and human amniotic fluid reduces epidural fibrosis and adhesions after spinal laminectomy in rat models. Further studies in humans are needed to determine the complications of the agents researched.