Nerve Crush Model In Rats Research Articles

A spatially specified systems pharmacology therapy for axonal recovery after injury.

There are no known drugs or drug combinations that promote substantial central nervous system axonal regeneration after injury. We used systems pharmacology approaches to model pathways underlying axonal growth and identify a four-drug combination that regulates multiple subcellular processes in the cell body and axons using the optic nerve crush model in rats. We intravitreally injected agonists HU-210 (cannabinoid receptor-1) and IL-6 (interleukin 6 receptor) to stimulate retinal ganglion cells for axonal growth. We applied, in gel foam at the site of nerve injury, Taxol to stabilize growing microtubules, and activated protein C to clear the debris field since computational models predicted that this drug combination regulating two subcellular processes at the growth cone produces synergistic growth. Physiologically, drug treatment restored or preserved pattern electroretinograms and some of the animals had detectable visual evoked potentials in the brain and behavioral optokinetic responses. Morphology experiments show that the four-drug combination protects axons or promotes axonal regrowth to the optic chiasm and beyond. We conclude that spatially targeted drug treatment is therapeutically relevant and can restore limited functional recovery.

Type I Collagen-Adhesive and ROS-Scavenging Nanoreactors Enhanced Retinal Ganglion Cell Survival in an Experimental Optic Nerve Crush Model.

Traumatic optic neuropathy (TON) is a severe condition characterized by retinal ganglion cell (RGC) death, often leading to irreversible vision loss, and the death of RGCs is closely associated with oxidative stress. Unfortunately, effective treatment options for TON are lacking. To address this, catalase (CAT) is encapsulated in a tannic acid (TA)/poly(ethylenimine)-crosslinked hollow nanoreactor (CAT@PTP), which exhibited enhanced anchoring in the retina due to TA-collagen adhesion. The antioxidative activity of both CAT and TA synergistically eliminated reactive oxygen species (ROS) to save RGCs in the retina, thereby treating TON. In vitro experiments demonstrated that the nanoreactors preserve the enzymatic activity of CAT and exhibit high adhesion to type I collagen. The combination of CAT and TA-based nanoreactors enhanced ROS elimination while maintaining high biocompatibility. In an optic nerve crush rat model, CAT@PTP is effectively anchored to the retina via TA-collagen adhesion after a single vitreous injection, and RGCs are significantly preserved without adverse events. CAT@PTP exhibited a protective effect on retinal function. Given the abundance of collagen that exists in ocular tissues, these findings may contribute to the further application of this multifunctional nanoreactor in ocular diseases to improve therapeutic efficacy and reduce adverse effects.

Anti-inflammatory effect of glucagon-like Peptide-1 receptor agonist on the neurosensory retina in an acute optic nerve injury rat model

PurposeTo explore the possibility of using glucagon-like peptide-1 receptor agonist (GLP-1RA) as a new treatment for neuroinflammation, by analyzing retinal pathological changes in an optic nerve crush rat model. MethodsEight-week-old male Sprague-Dawley rats were divided into lixisenatide (LIX, n = 10), traumatic control (T-CON, n = 10), and normal control (n = 5) groups. The optic nerves of left eyes in the LIX and T-CON groups were crushed in a standardized manner. The LIX group was treated with subcutaneous injections of lixisenatide (200 μg/kg/day) for 5 days. One week after initiating treatment, quantitative polymerase chain reaction, Western blot, and immunohistochemistry analyses were performed on the retinal tissues of each group to identify inflammatory markers. ResultsThe LIX group showed significantly lower mRNA levels of interleukin 1 beta (IL-1β), tumor necrosis factor-alpha (TNF-α), thioredoxin interacting protein (TXNIP), and glial fibrillary acidic protein (GFAP) than the T-CON group. Also, the LIX group exhibited decreased TXNIP and GFAP expression compared with the T-CON group, and similar expression to the normal control group, according to Western blot analysis. Significantly increased immunohistochemistry staining of Brn3a and decreased TUNEL staining were seen in the LIX group compared with the T-CON group, indicating that lixisenatide contributes to retinal ganglion cell survival in cases of acute optic nerve injury. ConclusionsNeuroinflammation was significantly reduced in lixisenatide-treated retinas compared with untreated retinas in our acute optic nerve injury rat model. The neuroprotective effect of lixisenatide indicates that it can serve a new treatment option against clinically intractable traumatic optic neuropathy.

N-acetylcysteine maintains penile length and erectile function in bilateral cavernous nerve crush rat model by reducing penile fibrosis.

Penile length shortening and erectile dysfunction are common complications after radical prostatectomy. Various methods have been used to maintain erectile function, but less attention has been paid to preserving penis length. N-acetylcysteine (NAC) has the effect of antioxidation and antifibrotic, which may be beneficial to improve those postoperative complications. This study investigated the effect of NAC on maintaining the penile length and the erectile function after bilateral cavernous nerve crush (BCNC) and its underlying mechanism. Twenty-four male rats were randomly divided into three groups: control group, BCNC group, and BCNC + NAC group. NAC or equal volume of saline was daily administrated by intragastric gavage for 4 weeks. The initial and end penile lengths were measured. Intracavernosal pressure/mean arterial pressure (ICP/MAP) ratio was calculated to assess erectile function. Hematoxylin–eosin staining, Masson's trichrome staining, immunohistochemistry, and Western blot were performed to explore cellular and molecular changes of the penis. Compared to the BCNC group, the penile length, ICP/MAP ratio and smooth muscle/collagen ratio in the BCNC + NAC group were improved significantly (all P < 0.05), and the expressions of endothelial nitric oxide synthase, α-smooth muscle actin, glutathione, and glutathione peroxidase 1 were significantly increased after NAC treated (all P < 0.05), along with the decreased expressions of hypoxia-inducible factor-1α, transforming growth factor-β1, collagen I, collagen III, collagen IV, malonaldehyde, and lysine oxidase (all P < 0.05). This study demonstrated that NAC could maintain penile length and partly improve erectile function. Possible mechanism is directly and/or indirectly related to antihypoxic and antifibrosis.

Neuroprotective effect of Lovastatin on motor deficit induced by sciatic nerve crush in the rat

Following severe peripheral nerve injury (PNI), regeneration is often insufficient and functional recovery is incomplete. Any agents that limit the spread of neural tissue damage may enhance the nerve regeneration. In this regard, statins have been shown to have neuroprotective properties. We investigated the effects of Lovastatin against sciatic nerve crush injury in male Wistar Rats. Lovastatin or vehicle was given parenteraly to rats for 7 days postoperative. In Lovastatin treatment groups, a single dose of agent (2 and 5mg/kg) was administered daily. The control group was given vehicle in the same manner. The rats were subjected to crush injury in the left sciatic nerve with non-serrated clamp for 30s. Behavioral, electrophysiological and morphological alterations were evaluated during the experimental period. Results showed that Lovastatin in a dose of 5mg/kg could significantly (P < 0.05) accelerate regeneration process and functional recovery. Also results demonstrated that morphometric parameters such as mean axonal number and myelin thickness were significantly higher in Lovastatin (5mg/kg) treatment groups compared to controls (P < 0.05). These findings suggest that a short-term course treatment with Lovastatin can protect against sciatic nerve injury. Findings indicate that postoperative administration of Lovastatin led to accelerate regeneration process and motor function recovery in nerve crush model in rats. This effect might be due to the anti-inflammatory, immunomodulatory or anti-oxidative properties of Lovastatin. It is clear that more research is needed to confirm these findings.

Neuroprotective effect of 4-(Phenylsulfanyl)butan-2-one on optic nerve crush model in rats

This study is to investigate the effect of coral-related compound, 4-(phenylsulfanyl)butan-2-one (4-PSB-2) on optic nerves (ON) and retinal ganglion cells (RGC) in a rat model subjected to ON crush. The ONs of adult male Wistar rat (150–180 g) were crushed by a standardized method. The control eyes received a sham operation. 4-PSB-2 (5 mg/kg in 0.2 mL phosphate-buffered saline) or phosphate-buffered saline (PBS control) was immediately administered after ON crush once by subcutaneous injection. Rats were euthanized at 2 weeks after the crush injury. RGC density was counted by retrograde labeling with FluoroGold (FG) application to the superior colliculus, and visual function was assessed by flash visual evoked potentials (FVEP). TUNEL assay, immunoblotting analysis of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX2) in the retinas, and immunohistochemistry of ED1 in the ON were evaluated. Two weeks after the insult, the RGC densities in the central and mid-peripheral retinas in ON-crushed, 4-PSB-2-treated rats were significantly higher than that of the corresponding ON-crushed, PBS-treated rats FVEP measurements showed a significantly better preserved latency of the P1 wave in the ON-crushed, 4-PSB-2-treated rats than the ON-crushed, PBS treated rats. TUNEL assays showed fewer TUNEL positive cells in the ON-crushed, 4-PSB-2-treated rats. The number of ED1 positive cells was reduced at the lesion site of the optic nerve in the ON-crushed, 4-PSB-2-treated group. Furthermore, administration of 4-PSB-2 significantly attenuated ON crush insult-stimulated iNOS and COX2 expression in the retinas. These results demonstrated that 4-PSB-2 protects RGCs and helps preserve the visual function in the rat model of optic nerve crush. 4-PSB-2 may work by being anti-apoptotic and by attenuation of the inflammatory responses involving less ED1 positive cells infiltration in ON as well as suppression of iNOS/COX-2 signaling pathway in the retinas to rescue RGCs after ON crush injury.

Protection of retinal ganglion cells from optic nerve injury by human umbilical cord blood stem cells transplantation

Objective To observe the protective effect of human umbilical cord blood stem cells (hUCBSC) transplantation on retinal ganglion cells (RGC) after optic nerve injury. Method 48 adult Sprague-Dawley rats were randomly divided into group A and B, therefore 24 rats in each group. Calibrated optic nerve crush injury model was induced in the left eyes, the right eyes served as a control. Medicine was injected at seventh day after optic nerve injury. PBS was injected into the eyes of Group A rats by peribulbar injection. The hUCBSCs were injected into the eyes of Group B rats by peribulbar injection. Seven days before sacrifice, 5% fluorogold was injected into superior colliculi bilaterally. At 7, 14, 21, 28 days after labeled, retinal flat mounts were observed under fluorescence microscope and optical microscope to investigate the morphological and RGC changes in density during retinal degeneration. Results The RGC number showed a tendency to decline gradually along with increases of the time in two groups, but the trend of decrease of Group B was evidently slower than that of Group A. The RGC number of the injury eye were less than the control eye in Group A and B (t=3.24, 3.15; P<0.05). At 7, 14, 21, 28 days after labeled, the RGC number (t=4.78, 4.70, 3.98, 3.27; P<0.05) and labeled RGC rate (t=4.39, 4.21, 4.36, 5.07; P<0.05) in group B were more than those in group A. After optic nerve injury, there was karyopycnosis on ganglion cell layer of retina, thinning on each layer of retina, derangement of cell and decrease in RGC. There was different degree of the above change in different time after optic nerve injury. There were the swelling, the hemorrhage, derangement of spongiocyte and the denaturation like vacuole in the spot of optic nerve injury. Moreover, they were aggravating with increases of the time after optic nerve injury. There was no pathological changes in normal eyes. Conclusion The hUCBSC can increase the survival rate of the RGC and can rescue and(or) restore the injujed RGC after transplanted into body of optic nerve crush rat model by peribulbar injection. Key words: Optic nerve injuries; Optic nerve diseases/therapy; Cord blood stem cell transplantation

Effects of intracavernous injection of adipose-derived stem cells on cavernous nerve regeneration in a rat model.

The aim of this study was to investigate effects of intracavernous injection of adipose-derived stem cells (ADSCs) on cavernous nerve (CN) regeneration and functional status in a nerve-crush rat model. Thirty Sprague-Dawley male rats were randomly divided into three equal groups: one group underwent sham operation, while two groups underwent bilateral CN crush. Crush-injury group was treated at the time of injury with intracavernous injection of ADSCs, or injured control group with no further intervention. Erectile function was assessed by CN electrostimulation after 3 months. Penile tissue and crushed nerves were collected for histology. Three months after surgery, in the group that underwent bilateral nerve crushing with no further intervention, the functional evaluation showed a lower mean maximal intracavernous pressure (ICP) and maximal ICP per mean arterial pressure (MAP) with CN stimulation than those in the sham group. In the group with an immediate intracavernous injection of ADSCs, the mean maximal ICP and maximal ICP/MAP were significantly higher than those in the injured control group. Histologically, the group with the intracavernous injection of ADSCs had more myelinated axons of CNs and more NADPH-diaphorase-positive nerve fibers than the injured control group but fewer than the sham group. Intracavernous injection of ADSCs treatment had beneficial effects on the smooth muscle/collagen ratio in the corpus cavernosum. These results show that the intracavernous injection of ADSCs to the site of CN-crush injury facilitates nerve regeneration and recovery of erectile function. Our research indicates that penile injection of ADSCs can improve recovery of erectile function in a rat model of neurogenic ED.

Effect of ginkgo biloba extract on recovery after facial nerve crush injury in the rat

Background and objectiveMany pharmacological agents have shown successful results in experimental crush injury of the peripheral nerve. To date, therapeutic effect of ginkgo biloba extract (GBE) on the peripheral nerve crush injury of rats has been rarely reported, moreover, neuroprotective effect on the facial nerve crush injury has not been reported. Materials and methodsProspective functional recovery, using a vibrissae movement and electrophysiological analysis of recovery 4 weeks after the facial nerve crush in adult rats, and comparison with randomized intraperitoneal injection of either GBE or control phosphate buffered saline. ResultsRelative to the control group (26 days post operation), administration of GBE significantly accelerated the recovery of vibrissae orientation to 11.7 days post the operation. A significant functional recovery was observed by postoperative 2nd week in the experimental group. The recovery of threshold and conduction velocity, postoperative 4th week in the experimental group, showed statistically significant difference compared to that of the control group. ConclusionFrom this result, intraperitoneal injection of GBE has been found effective in promoting the regeneration of the nerve in an experimental facial nerve crush rat model. Further studies, including morphological and molecular analyses, are necessary to clarify the mechanisms of GBE on the facial nerve crush.

Evaluation of a partial optic nerve crush model in rats

This study was performed to determine whether a partial optic nerve crush (PONC) model in rats is effective and reliable for the study of optic nerve protection and regeneration. Bilateral superior colliculus (SC) retrograde 1,1′-dioctadecyl-3,3,3′,3′-tetramethylindocarbocyanine perchlorate (DiI) labeling of retinal ganglion cells (RGCs; n=3) and unilateral SC retrograde labeling of RGCs (n=3) were performed in adult Sprague-Dawley (SD) rats and the results were compared with the bilateral and unilateral SC retrograde-labeled RGCs. Another 40 adult SD rats, three days after bilateral SC retrograde DiI labeling of RGCs underwent crushing with a non-invasive vascular clip (40 gram power) 1 mm behind the right optic nerve head for 5, 10 and 30 sec (n=10 each), and a sham-operated control group (n=10) was used as a control. The retinas of all 40 rats were flattened by four radial cuts, mounted vitreal side-up on gelatin-coated slides, and the number of labeled RGCs was counted in four distinct regions per retinal quadrant at three different eccentricities of 1/6, 3/6 and 5/6 of the retinal radius three days later. Bilateral SC retrograde DiI injection labeled the majority of normal RGCs, while unilateral SC injections only labeled a small part of the RGCs; the majority of RGCs were not labeled. In the mild crush (5 sec) injury group, the bilateral SC retrograde DiI injection labeled the majority of RGCs. The RGC densities at 1/6, 3/6 and 5/6 of the retinal radius showed no significant difference compared with the RGC densities at the corresponding region of the retinal radius in the sham-operated control group (P=0.734, 0.461, 0.273, respectively). In the moderate crush injury (10 sec) group, the number of labeled RGCs was significantly lower compared to that of the sham-operated control group, and the RGC densities at 1/6, 3/6, 5/6 of the retinal radius were significantly lower compared to the RGC densities at the corresponding retinal radius in the sham-operated control group (P<0.001). In the severe crush injury (30 sec) group the number of labeled RGCs was significantly decreased, and the labeled RGCs were not observed in the region at 5/6 of the retinal radius. The RGC densities at 1/6 and 3/6 of the retinal radius were significantly lower compared to the RGC densities at the corresponding retinal radius region in the sham-operated control group (P<0.001). Compared with the mild and severe optic nerve crush injury models, the moderate crush injury model is more suitable for the study of optic nerve damage and regeneration.

Neuroprotective mechanisms of human umbilical cord blood stem cells to retinal ganglion cells in a partial optic nerve crush rat model

Background Optic nerve injury lead to apoptosis of retinal ganglion cells ( RGCs ), and its mechanism of apoptosis is endoplasmic reticulum stress (ERS). So, decreasing of ERS may protect the injury of RGCs. Objective The present study was to investigate the mechanisms of endoplasmic reticulum stress(ERS) and the protective effects of human umbilical cord blood stem cells on partial optic nerve crush injury. Methods The optical nerves were crushed with a 40 g clip by holding for 60 seconds to establish the partial optical nerve injury model in the left eyes of 102 SPF SD rats,and 10 μl of mRNA and 10 μl of nerve growth factor were injected into the vitreous immediately after the establishment of the model. The morphological changes of retinal ganglion cells(RGCs) were examined under the light microscope after 3,7,14,21 and 28 days and the RGCs number was calculated. The apoptosis rates of RGCs were detected by the TUNEL technique after 3, 12,24,45,72 hours and 1 week. The expression levels of GRP78 mRNA and CHOP mRNA were detected by reverse transcription polymerase chain reation (RT-PCR). This procedure followed the Regulations for the Administration of Affair Concerning Experimental Animals by Hunan Provincial Science and Technology Committee.Results The number of RGCs was significantly decreased with the prolongation of time of optical nerve injury in the model injury group,whereas the number of RGCs in the human cord blood cells group was reduced at a slower rate( Ftime =20. 100,P =0. 007 ). At various time points after the injection of human cord blood cells, the survival of RGCs was evidently increased in comparison with the model group(P＜0. 01 ). The apoptosis rate of RGCs was considerably elevated with injury time prolongation both in the model group and human cord blood cells group,but no apoptosis was seen from 3-24 hours after operation,and only a small amount of apoptotic cells were found in the human cord blood cells group from 48 hours through 1 week than in the model group(P＜0. 01 ). In the human cord blood cells group,GRP78 mRNA level was significantly higher and the CHOP mRNA level was significantly lower than those in the injury group at identical time points(P＜0. 01 ). Conclusions In the rat optic nerve partial crush model,ERS induces the apoptosis of RGCs. Human umbilical cord blood stem cells can protect RGCs from ERS injury by inhibiting apoptosis. Key words: Human umbilical cord blood stem cell; Endoplasmic reticulum stress; GRP78; CHOP; Optic nerve/crush

Neuroprotective effect of epigallocatechin-3-gallate on retinal ganglion cells in optic nerve crush rat model

Objective To investigate the neuroprotective effect of epigallocatechin-gallate (EGCG),the major catechin found in green tea, in an optic nerve crush (ONC) rat model. Methods Seventy-two Wistar rats were divided randomly into four groups: normal control, sham-operation+ EGCG, ONC+vehicle, and ONC+ EGCG groups. Animals were treated intraperitoneally and orally with either vehicle (normal saline) or EGCG (25 mg/kg, injected daily for up to five days, and orally 2 mg/kg daily afterwards). Two days after the first injection, an ONC injury using a micro optic nerve clipper was performed at approximately 2 mm from the optic nerve head for 60 seconds. Fluorogold was injected into bilateral superior colliculi five days before sacrifice and fluorescent gold labeled retinal ganglion cells (RGC)were counted under fluorescence microscopy on days seven, 14 and 28 after optic nerve crush. Meanwhile,the expression of neurofilament triplet L (NF-L) was measured by immunohistochemistry and Western blotting. Results In the ONC + vehicle group, a progressive loss of RGC was observed;however,compared with the ONC+vehicle group, RGC density was significantly higher on day seven (t=3. 216, P=0. 009), day 14 (t=2. 609, P=0. 026) and day 28 (t=2. 792, P=0. 019) , and a significant increase of theNF-L protein expression has been observed on days seven, 14 and 28 after optic nerve crush in the ONC+EGCG group. Conclusions EGCG has a protective effect to the bodies and axons of the RGC after optic nerve crush. Key words: Optic nerve injuries; Callic acid /therapeutic use; Retinal ganglion cells; Animal experimentation

Neuroprotective effects of Epigallocatechin-3-gallate (EGCG) in optic nerve crush model in rats

Epigallocatechin-3-gallate (EGCG), the major catechin found in green tea, is a powerful antioxidant and has anti-inflammatory with neuroprotective potential. This study aims to investigate the neuroprotective effects of EGCG in an optic nerve crush (ONC) model in rats. Seventy-two Wistar rats were randomly divided into four groups: normal control (group A), sham operation + EGCG (group B), ONC + vehicle (group C), and ONC + EGCG (group D). The rats were treated intraperitoneally and orally with either vehicle or EGCG (25 mg/kg, injected daily for 5 days and 2 mg/kg orally daily afterwards). Two days after the first injection, an ONC injury was performed by using a micro optic nerve clipper with 40 g power at approximately 2 mm from the optic nerve head for 60 s. Fluorogold was injected into the bilateral superior colliculi 5 days before sacrifice and fluorescent gold-labelled retinal ganglion cells (RGCs) were counted under fluorescence microscopy on days 7, 14 and 28 after ONC. The expression of Neurofilament triplet L (NF-L) was measured via immunohistochemical and Western blotting analysis. In group C, a progressive loss of RGCs was observed after ONC. In contrast, the density of RGCs was significantly higher in group D ( p = 0.009, independent samples t-test) on day 7 after ONC, and statistical differences were obtained on days 14 and 28 ( p = 0.026 and p = 0.019, respectively, independent samples t-test). The results of immunohistochemical and Western blotting analysis showed significantly higher NF-L protein expression in group D in comparison with group C on days 7, 14 and 28 after ONC. These findings suggest that there are protective effects of EGCG on RGCs after ONC, indicating EGCG might be a potential therapeutic agent for optic nerve diseases.

Design and Application of a New Rat‐Specific Vacuum Erectile Device for Penile Rehabilitation Research

Radical prostatectomy has a potential negative impact on penile health. The vacuum erection device (VED) has been used to promote the recovery of penile function and to maintain penile length. However, there is skepticism in the urological community due to its elusive mechanisms in penile rehabilitation. To design a rat-specific VED and assess its application and safety. Based on rat penile measurement and the principle of human VED, the rat-specific VED was designed, and the application for rats was evaluated. The vacuum pressure of the rat-specific VED was measured. The VED application on rat penis and its side effects were studied. The rat-specific VED is a safe and applicable device to study the mechanism of VED in penile rehabilitation. The newly designed rat-specific VED is a good simulator of the human VED. The application of this device on bilateral cavernous nerve crush rat model will be used to study the mechanisms of the VED in the penile rehabilitation.

Neuroprotective effects of tempol on retinal ganglion cells in a partial optic nerve crush rat model with and without iron load

Iron overload can contribute to oxidative stress in many tissues. We studied the effects of pretreatment with iron dextran on RGC loss in a calibrated partial optic nerve crush (PONC) model in rats, along with the protection offered by tempol (4-hydroxy-2,2,6,6-tetramethylpiperidinyl-1-oxyl, a membrane-permeable superoxide dismutase mimetic and free-radical scavenger), in the same experimental paradigm. A total of 40 rats in 6 groups of 5–8 animals each underwent PONC in one eye and sham crush in the other. Animals were pretreated with a single iron dextran load 24 h prior to PONC, and treated with tempol 6 h before and then once daily after PONC. Control animals were treated with PBS. RGC were retrogradely labeled with a fluorescent marker; all data are expressed in percent of the RGC count in the respective sham-treated eye. Immunohistochemistry was performed to visualize 3-nitrotyrosine, a marker of nitroxidative stress. PONC without iron pretreatment resulted in the survival of only 31.4% of labeled RGC after 7 days. Even fewer RGC (12.7%) survived after PONC with iron pretreatment. However, tempol in doses of 20 mg/kg of body weight (BW) significantly attenuated this effect when given as described above; in the group without iron pretreatment the number of surviving RGC doubled from 31.4% to 62.1%. In the group with iron pretreatment the survival rate of RGC increased even more pronouncedly, from 12.7% without tempol to 46.2% with tempol. Tempol in doses of 1 mg/kg BW and 5 mg/kg BW showed no significant rescue of RGC. Immunostaining showed nitrotyrosine-positive RGCs in PONC but not in sham-treated eyes and an increase in positive cells after iron load. Tempol treatment reduced nitrotyrosine staining in both the iron and non-iron groups. Our results demonstrate that PONC results in significantly greater RGC damage when iron pretreatment is performed, and that the compound tempol may provide additional protection for RGC in cases of neuronal damage both with and without prior iron treatment.

The effect of platelet-rich plasma on cavernous nerve regeneration in a rat model

The aim of this study was to investigate the effect of platelet-rich plasma (PRP) on cavernous nerve (CN) regeneration and functional status in a nerve-crush rat model. Twenty-four Sprague-Dawley male rats were randomly divided into three equal groups: eight had a sham operation, eight underwent bilateral nerve crushing with no further intervention and eight underwent bilateral nerve crushing with an immediate application of PRP on the site of injury. Erectile function was assessed by CN electrostimulation at 3 months and nerve regeneration was assessed by toluidine blue staining of CN and nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase staining of penile tissue. Three months after surgery, in the group that underwent bilateral nerve crushing with no further intervention, the functional evaluation showed a lower mean maximal intracavernous pressure (ICP) and maximal ICP per mean arterial pressure (MAP) with CN stimulation than those in the sham group. In the group with an immediate application of PRP, the mean maximal ICP and maximal ICP/MAP were significantly higher than those in the injured control group. Histologically, the group with the application of PRP had more myelinated axons of CNs and more NADPH-diaphorase-positive nerve fibres than the injured control group but fewer than the sham group. These results show that the application of PRP to the site of CN-crush injury facilitates nerve regeneration and recovery of erectile function. Our research indicates that clinical application of PRP has potential repairing effect on CN and peripheral nerves.

An Analysis of Time-Dependent Changes of Neurotrophic Factors (BDNF, CNTF) in Traumatic Facial Nerve Injury of a Nerve-Cut and Nerve-Crush Model in Rats

To investigate neurotrophic changes in the injured facial nerve in rats. Time-dependent follow-up of brain-derived neurotrophic factor (BDNF) and ciliary neurotrophic factor (CNTF) concentrations in a standardized nerve-cut and nerve-crush trauma model could present valuable information about estimation of the extent of the injury. Ninety Wistar rats were grouped into permanent (transection: nerve-cut) and transient (compression: nerve-crush) nerve injury and analyzed for neurotrophic changes at Week 1 and after 1, 3, and 6 months. Ten undissected rats served as controls. Permanent injury was accomplished with a 5-mm transection. To model transient injury, the facial nerve was pressed by vascular clamps for 40 minutes. Rat BDNF and CNTF enzyme-linked immunosorbent assay kits were used to perform histochemical analysis of blood samples. Measurements were compared with variance analysis and Student's t tests. BDNF levels in nerve-injured preparations from both groups at consecutive intervals were not significant from those of controls, except for transient increases in the first week. When BDNF levels in nerve-cut and nerve-crush groups were compared at each interval separately, differences were insignificant (p > 0.05). CNTF levels at consecutive intervals were significant from that of control rats in both groups. When CN0054F levels in nerve-cut and nerve-crush groups were compared at each interval separately, differences were significant (p = 0.023, p = 0.001, p = 0.043, and p = 0.023). Elevated levels of BDNF in the first week after nerve injury do not differentiate the severity of the facial nerve injury. However, diminished CNTF levels in the nerve-crush group were significant when compared with that of nerve-cut group. This finding suggests the possibility that CNTF levels can distinguish whether the facial nerve is interrupted after trauma. Further experimental studies should investigate the indicative role of CNTF levels as a marker of nerve disruption in the clinical setting.

POLY(ADENOSINE DIPHOSPHATE-RIBOSE) POLYMERASE INHIBITION PRESERVES ERECTILE FUNCTION IN RATS AFTER CAVERNOUS NERVE INJURY

We investigated the involvement of poly(adenosine diphosphate-ribose) (PAR) polymerase (PARP) activation in the development of erectile dysfunction and the therapeutic benefit of the potent PARP inhibitor INO-1001 (Inotek Pharmaceuticals Corp., Beverly, Massachusetts) in a bilateral cavernous nerve crush injury (BCNCI) model in rats. Sprague-Dawley rats were divided into 3 groups, namely sham treated, BCNCI plus vehicle and BCNCI plus the PARP inhibitor INO-1001. One week after surgical intervention all groups underwent in vivo cavernous nerve stimulation. PAR activation, nitrotyrosine and inducible nitric oxide synthase were evaluated by immunohistochemistry and serum levels of INO-1001 were measured by high performance liquid chromatography. Penile tissues were analyzed for levels of malondialdehyde and myeloperoxidase. Data sets were statistically compared in all groups. Neurogenic mediated erectile responses were evaluated. Mean intracavernous pressure (ICP), the ICP-to-blood-pressure ratio and total ICP were significantly decreased in BCNCI plus vehicle rats. These values were not statistically different between the sham and PARP inhibitor treated groups. There was a marked decrease in PAR staining in the treatment group. There was a substantial increase in malondialdehyde tissue levels but not myeloperoxidase in response to BCNCI, which was unchanged with PARP inhibitor treatment. There was a marked increase in tyrosine nitration in the treatment group. Up-regulation of nitric oxide synthase and increased tyrosine nitration were not observed in the penile tissues of the treatment group. These data demonstrate that BCNCI in a rat model causes increased PARP activation, resulting in severe erectile dysfunction. Treatment with the PARP inhibitor INO-1001 decreases the degree of nitrosative stress, prevents PARP activation and provides significant cavernous neuroprotection, which in turn preserves erectile function.