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The peripheral nervous system can encounter alterations due to exposure to some of the most commonly used anticancer drugs (platinum drugs, taxanes, vinca alkaloids, proteasome inhibitors, thalidomide), the so-called chemotherapy-induced peripheral neurotoxicity (CIPN). CIPN can be long-lasting or even permanent, and it is detrimental for the quality of life of cancer survivors, being associated with persistent disturbances such as sensory loss and neuropathic pain at limb extremities due to a mostly sensory axonal polyneuropathy/neuronopathy. In the state of the art, there is no efficacious preventive/curative treatment for this condition. Among the reasons for this unmet clinical and scientific need, there is an uncomplete knowledge of the pathogenetic mechanisms. Ion channels and transporters are pivotal elements in both the central and peripheral nervous system, and there is a growing body of literature suggesting that they might play a role in CIPN development. In this review, we first describe the biophysical properties of these targets and then report existing data for the involvement of ion channels and transporters in CIPN, thus paving the way for new approaches/druggable targets to cure and/or prevent CIPN.

Peripheral neurotoxicity is a dose-limiting adverse reaction of primary frontline chemotherapeutic agents, including vincristine. Neuropathy can be so disabling that patients drop out of potentially curative therapy, negatively impacting cancer prognosis. The hallmark of vincristine neurotoxicity is axonopathy, yet its underpinning mechanisms remain uncertain. We developed a comprehensive drug discovery platform to identify neuroprotective agents against vincristine-induced neurotoxicity. Among the hits identified, SIN-1-an active metabolite of molsidomine-prevents vincristine-induced axonopathy in both motor and sensory neurons without compromising vincristine anticancer efficacy. Mechanistically, we found that SIN-1's neuroprotective effect is mediated by activating soluble guanylyl cyclase. We modeled vincristine-induced peripheral neurotoxicity in rats to determine molsidomine therapeutic potential in vivo. Vincristine administration induced severe nerve damage and mechanical hypersensitivity that were attenuated by concomitant treatment with molsidomine. This study provides evidence of the neuroprotective properties of molsidomine and warrants further investigations of this drug as a therapy for vincristine-induced peripheral neurotoxicity.

Paclitaxel-induced peripheral neurotoxicity (PIPN) is a potentially dose-limiting side effect in anticancer chemotherapy. Several animal models of PIPN exist, but their results are sometimes difficult to be translated into the clinical setting. We compared 2 widely used PIPN models characterized by marked differences in their methodologies. Female C57BL/6JOlaHsd mice were used, and they received only paclitaxel vehicle (n = 38) or paclitaxel via intravenous injection (n = 19, 70 mg/kg) once a week for 4 weeks (Study 1) or intraperitoneally (n = 19, 10 mg/kg) every 2 days for 7 times (Study 2). At the end of treatment and in the follow-up, mice underwent behavioral and neurophysiological assessments of PIPN. At the same time points, some mice were killed and dorsal root ganglia, skin, and sciatic and caudal nerve samples underwent pathological examination. Serum neurofilament light levels were also measured. The differences in the neurotoxicity parameters were analyzed using a nonparametric Mann-Whitney test, with significance level set at P < 0.05. Study 1 showed significant and consistent behavioral, neurophysiological, pathological, and serological changes induced by paclitaxel administration at the end of treatment, and most of these changes were still evident in the follow-up period. By contrast, study 2 evidenced only a transient small fiber neuropathy, associated with neuropathic pain. Our comparative study clearly distinguished a PIPN model recapitulating all the clinical features of the human condition and a model showing only small fiber neuropathy with neuropathic pain induced by paclitaxel.

Background and Aims: Chemotherapy-induced peripheral neurotoxicity (CIPN) is one of the most common dose-limiting side effects of paclitaxel (PTX) treatment. Many age-related changes have been hypothesized to underlie susceptibility to damage or impaired regeneration/repair after nerve injury. The results of these studies, however, are inconclusive and other potential biomarkers of nerve impairment need to be investigated. Methods: Twenty-four young (2 months) and 24 adult (9 months) Wistar male rats were randomized to either PTX treatment (10 mg/kg i.v. once/week for 4 weeks) or vehicle administration. Neurophysiological and behavioral tests were performed at baseline, after 4 weeks of treatment and 2-week follow-up. Skin biopsies and nerve specimens collected from sacrificed animals were examined for intraepidermal nerve fiber (IENF) density assessment and nerve morphology/morphometry. Blood and liver samples were collected for targeted metabolomics analysis. Results: At the end of treatment, the neurophysiological studies revealed a reduction in sensory nerve action potential amplitude (p <.05) in the caudal nerve of young PTX-animals, and in both the digital and caudal nerve of adult PTX-animals (p <.05). A significant decrease in the mechanical threshold was observed only in young PTX-animals (p <.001), but not in adult PTX-ones. Nevertheless, both young and adult PTX-rats had reduced IENF density (p < .0001), which persisted at the end of follow-up period. Targeted metabolomics analysis showed significant differences in the plasma metabolite profiles between PTX-animals developing peripheral neuropathy and age-matched controls, with triglycerides, diglycerides, acylcarnitines, carnosine, long chain ceramides, sphingolipids, and bile acids playing a major role in the response to PTX administration. Interpretation Our study identifies for the first time multiple related metabolic axes involved in PTX-induced peripheral neurotoxicity, and suggests age

Background and Aims: Chemotherapy-induced peripheral neurotoxicity (CIPN) is a common and long-lasting adverse event of several anticancer compounds, for which treatment has not yet been developed. To fill this gap, preclinical studies are warranted, exploiting highly translational outcome measure(s) to transfer data from bench to bedside. Nerve excitability testing (NET) enables to test in vivo axonal properties and can be used to monitor early changes leading to axonal damage. Methods: We tested NET use in two different CIPN rat models: oxaliplatin (OHP) and paclitaxel (PTX). Animals (female) were chronically treated with either PTX or OHP and compared to respective control animals. NET was performed as soon as the first injection was administered. At the end of the treatment, CIPN onset was verified via a multimodal and robust approach: nerve conduction studies, nerve morphometry, behavioural tests and intraepidermal nerve fibre density. Results: NET showed the typical pattern of axonal hyperexcitability in the 72 h following the first OHP administration, whereas it showed precocious signs of axonal damage in PTX animals. At the end of the month of treatment, OHP animals showed a pattern compatible with a mild axonal sensory polyneuropathy. Instead, PTX cohort was characterised by a rather severe sensory axonal polyneuropathy with minor signs of motor involvement. Interpretation: NET after the first administration demonstrated the ongoing OHP-related channelopathy, whereas in PTX cohort it showed precocious signs of axonal damage. Therefore, NET could be suggested as an early surrogate marker in clinical trials, to detect precocious changes leading to axonal damage.

Oxaliplatin (OHP)-induced peripheral neurotoxicity (OIPN), one of the major dose-limiting side effects of colorectal cancer treatment, is characterized by both acute and chronic syndromes. Acute exposure to low dose OHP on dorsal root ganglion (DRG) neurons is able to induce an increase in intracellular calcium and proton concentration, thus influencing ion channels activity and neuronal excitability. The Na+/H+ exchanger isoform-1 (NHE1) is a plasma membrane protein that plays a pivotal role in intracellular pH (pHi) homeostasis in many cell types, including nociceptors. Here we show that OHP has early effects on NHE1 activity in cultured mouse DRG neurons: the mean rate of pHi recovery was strongly reduced compared to vehicle-treated controls, reaching levels similar to those obtained in the presence of cariporide (Car), a specific NHE1 antagonist. The effect of OHP on NHE1 activity was sensitive to FK506, a specific calcineurin (CaN) inhibitor. Lastly, molecular analyses revealed transcriptional downregulation of NHE1 both in vitro, in mouse primary DRG neurons, and in vivo, in an OIPN rat model. Altogether, these data suggest that OHP-induced intracellular acidification of DRG neurons largely depends on CaN-mediated NHE1 inhibition, revealing new mechanisms that OHP could exert to alter neuronal excitability, and providing novel druggable targets.

Peripheral Neuropathies (PN) are common conditions whose treatment is still lacking in most cases. Animal models are crucial, but experimental procedures should be refined in some cases. We performed a detailed characterization of the ventral caudal nerve to contribute to a more effective assessment of axonal damage in future PN studies. PN was induced via weekly systemic injection of a neurotoxic drug (paclitaxel); we compared the control and PN-affected rats, performing serial neurophysiological evaluations of the caudal nerve for its entire length. On the same nerve portions, we performed light microscopy and ultrastructural pathological observations to assess the severity of damage and verify the integrity of the surrounding structures. Neurophysiological and morphological analyses confirmed that a severe axonopathy had ensued in the PN group, with a length-dependent modality, matching morphological observations. The site of neurophysiological recording (e.g., distance from the base of the tail) was critical for achieving useful data. A flexible experimental paradigm should be considered in animal studies investigating axonal PN, particularly if the expected severity is relevant; the mid-portion of the tail might be the most appropriate site: there damage might be remarkable but neither as extreme as at the tip of the tail nor as mild as at the base of the tail.

Glioblastoma is the most common and aggressive brain tumor, associated with poor prognosis and survival, representing a challenging medical issue for neurooncologists. Dysregulation of histone-modifying enzymes (HDACs) is commonly identified in many tumors and has been linked to cancer proliferation, changes in metabolism, and drug resistance. These findings led to the development of HDAC inhibitors, which are limited by their narrow therapeutic index. In this work, we provide the proof of concept for a delivery system that can improve the in vivo half-life and increase the brain delivery of Givinostat, a pan-HDAC inhibitor. Here, 150-nm-sized liposomes composed of cholesterol and sphingomyelin with or without surface decoration with mApoE peptide, inhibited human glioblastoma cell growth in 2D and 3D models by inducing a time-and dose-dependent reduction in cell viability, reduction in the receptors involved in cholesterol metabolism (from −25% to −75% of protein levels), and reduction in HDAC activity (−25% within 30 min). In addition, liposome-Givinostat formulations showed a 2.5-fold increase in the drug half-life in the bloodstream and a 6-fold increase in the amount of drug entering the brain in healthy mice, without any signs of overt toxicity. These features make liposomes loaded with Givinostat valuable as potential candidates for glioblastoma therapy.

Pharmacogenomics is a powerful tool to predict individual response to treatment, in order to personalize therapy, and it has been explored extensively in oncology practice. Not only efficacy on the malignant disease has been investigated but also the possibility to predict adverse effects due to drug administration. Chemotherapy-induced peripheral neurotoxicity (CIPN) is one of those. This potentially severe and long-lasting/permanent side effect of commonly administered anticancer drugs can severely impair quality of life (QoL) in a large cohort of long survival patients. So far, a pharmacogenomics-based approach in CIPN regard has been quite delusive, making a methodological improvement warranted in this field of interest: even the most refined genetic analysis cannot be effective if not applied correctly. Here we try to devise why it is so, suggesting how THE "bench-side" (pharmacogenomics) might benefit from and should cooperate with THE "bed-side" (clinimetrics), in order to make genetic profiling effective if applied to CIPN.

The onset of chemotherapy-induced peripheral neurotoxicity (CIPN) is a leading cause of the dose reduction or discontinuation of cancer treatment due to sensory symptoms. Paclitaxel (PTX) can cause painful peripheral neuropathy, with a negative impact on cancer survivors’ quality of life. While recent studies have shown that neuroinflammation is involved in PTX-induced peripheral neurotoxicity (PIPN), the pathophysiology of this disabling side effect remains largely unclear and no effective therapies are available. Therefore, here we investigated the effects of human intravenous immunoglobulin (IVIg) on a PIPN rat model. PTX-treated rats showed mechanical allodynia and neurophysiological alterations consistent with a severe sensory axonal polyneuropathy. In addition, morphological evaluation showed a reduction of intra-epidermal nerve fiber (IENF) density and evidenced axonopathy with macrophage infiltration, which was more prominent in the distal segment of caudal nerves. Three weeks after the last PTX injection, mechanical allodynia was still present in PTX-treated rats, while the full recovery in the group of animals co-treated with IVIg was observed. At the pathological level, this behavioral result was paralleled by prevention of the reduction in IENF density induced by PTX in IVIg co-treated rats. These results suggest that the immunomodulating effect of IVIg co-treatment can alleviate PIPN neurotoxic manifestations, probably through a partial reduction of neuroinflammation.

Neurotoxicity is the most debilitating non-haematological adverse effect of paclitaxel (PTX) in cancer patients. Symptoms are typical of a sensory peripheral neuropathy and the incidence and degree are dependent on the cumulative dose. The symptoms include paraesthesia, disaesthesia, tingling, and numbness. Moreover, many patients develop allodynia and hyperalgesia, experiencing a severe neuropathic pain (NP). NP can originate from a peripheral sensitization then transmitted to upper centers in the central nervous system where it can determine structural and functional changes (altered neuronal discharge patterns). Preliminary evidences in other NP models showed an abundant microvascular neoangiogenesis in the primary somatosensory cortex, specifically on the hindlimb projection. The aim of this work is to investigate the microstructural vascular anomalies both in the central somatosensory pathway and peripheral (dorsal root ganglia, DRG) compartments in rats exposed to chronic PTX treatment. We treated 24 rats with PTX 10 mg/kg once a week for 4 weeks to induce a painful peripheral neuropathy. Animals were tested for neurophysiological abnormalities and behavioral NP before and after treatment. Then animals were sacrificed and perfused with fixative and/or indian-ink before collecting samples. Samples have been analyzed at synchrotron radiation resources by X-ray Phase-Contrast Tomography (XPCT) Imaging (Diamond, Didcot, UK and ESRF, Grenoble, France). Volume rendering allowed for a detailed visualization of vasculature at the sub micrometric scale. Quantitative and morphological analyses of micro-vascular structures with comparative comparisons between control and NP rats. Histochemical and histological evaluations have been performed to validate the results obtained by XPCT. A significant increased number of vessels has been found in NP samples, suggesting a neoangiogenesis at the capillary level in NP condition. The effect was larger (about +173%) on central sta

Dorsal root ganglia (DRG) sensitive neurons represent the connection between the peripheral sensorial receptors and the central nervous system. These neurons are enwrapped individually by the satellite glial cells (SCGs) from which they receive metabolic support. Together, neuron and SCGs, become a functional unit that, in absence of the blood brain barrier, is easily exposed to external stress and damage insults. This intimate connection/relationship, both morphological and functional, can be partially pictured and studied following traditional slicing 2D histopathological techniques. Indeed, morphological cellular and subcellular alterations and changes in protein expression and/or distribution can be observed using classical techniques. However, a whole-3D approach avoids the serial sectioning required for quantitative results plus is able to show the cyto-architecture of the organ and a more complete picture of the anatomical relationship between cell populations close to physiological conditions. Here we use a 3D imaging technique to show the cyto-architecture of the DRG after “colouring” by immunofluorescence the different DRG cell populations and to assess alterations in DRG of neuropathic rats. CGRP, IB4 and MAP2 markers were useful to study the different neuronal populations. The IB4-MAP2 combination was able to label all neurons while the CGRP-IB4 couple could not but still both settings showed a small subpopulation of neurons where the proteins were co-expressed. Moreover, GFAP, ATF3 and connexin 43 were used as markers of damage in the DRG from neuropathic animals.

Neurotoxicity is the most debilitating non-haematological adverse effect of paclitaxel (PTX) in cancer patients that report typical symptoms of a dose cumulative sensory peripheral neuropathy with paraesthesia, disaesthesia, tingling, and numbness. Many patients develop allodynia and hyperalgesia, experiencing neuropathic pain (NP). NP can originate from a peripheral sensitization then transmitted to the central nervous system where it can determine structural and functional changes. An abundant microvascular angiogenesis was described in the primary somatosensory cortex, specifically on the hindlimb projection of rats with NP of other origin. In this work, we investigated the microstructural vascular anomalies in the central somatosensory pathway and peripheral compartments (dorsal root ganglia, DRG) in rats exposed to chronic PTX treatment. Twenty-four rats were chronically treated with PTX 10 mg/kg to induce a painful peripheral neuropathy. Animals were tested for neurophysiological abnormalities and behavioral NP and finally perfused with fixative and/or indian ink before collecting samples. Samples have been analyzed at synchrotron radiation resources by X-ray Phase-Contrast Tomography (XPCT) Imaging (Diamond, Didcot, UK and ESRF, Grenoble, France). Volume rendering allowed a detailed visualization of vasculature at the sub micrometric scale. We performed a quantitative and morphological analysis of micro-vascular structures in PNS and CSN of control and NP rats. Histochemical and histological evaluations validated the results obtained by XPCT. A significant increased number of vessels has been found in NP samples, suggesting an angiogenesis at the capillary level in NP condition. The effect was larger (about +173%) in somatosensory cortex, still relevant in lumbar spinal cord and noticeable in related DRG. Specific analyses indicated that neo-formed vessels were smaller than 15 micron. Moreover, a significant decrement of the number of capillary branch points

Chemotherapy-induced peripheral neurotoxicity represents one of the most relevant dose-limiting side effects that can affect cancer patients treated with the common antineoplastic agents. Since the severity of neurotoxicity often leads to dose reduction or early cessation of chemotherapy, the investigation of molecular mechanisms underlying chemotherapy-induced peripheral neurotoxicity is an urgent clinical need in order to better understand its physiopathology and find effective strategies for neuroprotection. Several in vivo preclinical models of chemotherapy-induced peripheral neurotoxicity have been developed but a great variability in mouse strain, dose, route of administration of the drug, treatment schedule and assessment of neurotoxicity is observed between the different published studies making difficult the comparison and interpretation of their results. In many of these studies only behavioural tests are used as outcome measures, while possible neurophysiological and neuropathological changes are not evaluated. In this study, focused on experimental oxaliplatin-induced peripheral neurotoxicity, we reproduced and compared four mouse models with very different drug dose (low or high dose-intensity) and treatment schedules (short or long-term treatment), selected from the literature. Using a multimodal assessment based on behavioural, neurophysiological and neuropathological methods, we evidenced remarkable differences in the results obtained in the selected animal models. This work suggests the importance of a multimodal approach including extensive pathological investigation to confirm the behavioural results.

Chemotherapy-Induced Peripheral Neurotoxicity (CIPN) is a severe and long-lasting side effect of anticancer therapy, which can severely impair patients’ quality of life. It is a sensory and length-dependent neuropathy, which predominantly affects large myelinated fibers. Easy and reliable monitoring of CIPN in patients is still an unmet clinical need. Since increasing clinical evidence supports the potential use of neurofilament light chain (NfL) as a biomarker of axonal injury, in this study we measured serum NfL levels in animals chronically treated with cisplatin (CDDP) and paclitaxel (PTX), two antineoplastic drugs with different neuronal targets. Wistar rats were treated with CDDP (2 mg/kg i.p. twice/week for 4 weeks) or PTX (10 mg/kg i.v. once/week for 4 weeks). Repeated serum NfL quantification was obtained using the Single Molecule Array (Simoa) technology. The onset and progression of peripheral neurotoxicity were evaluated through neurophysiology, morphological assessments and intraepidermal nerve fibers density quantification. Our results showed that serum NfL measurements correlated with the severity of axonal damage. In fact, both treatments induced serum NfL increase, but higher levels were evidenced in PTX-treated animals, compared with CDDP-treated rats, affected by a milder neurotoxicity. Notably, also the timing of the NfL level increase was associated with the severity of morphological and functional alterations of axonal structure. Therefore, NfL could be a useful biomarker for axonal damage in order to follow the onset and severity of axonal degeneration and possibly limit the occurrence of serious PNS disease.

Oxaliplatin (OHP) Induced Peripheral Neurotoxicity (OIPN) is one of the dose-limiting toxicities of the drug and these adverse effects limit cancer therapy with L-OHP, used for colorectal cancer treatment. Acute neurotoxicity consists of symptoms that are the hallmarks of a transient axonal hyperexcitability; chronic neurotoxicity has a clinical picture compatible with a length-dependent sensory neuropathy. Acute OIPN pathogenesis has been linked to sodium voltage-operated channels (Na + VOC) dysfunction and it has been advocated as a possible predisposing factor to chronic neurotoxicity. We tested if topiramate (TPM), a well-known Na + VOC modulator, was able to modify acute as well as chronic OIPN. The project was divided into two parts. In Experiment 1 we tested by means of Nerve Excitability Testing (NET) a cohort of female Wistar rats to assess TPM effects after a single OHP administration (5 mg/kg, iv). In Experiment 2 we assessed TPM effects after chronic OHP treatment (5 mg/kg, 2qw4ws, iv) using NET, nerve conduction studies (NCS), behavioral tests and neuropathology (caudal nerve morphometry and morphology and Intraepidermal Nerve Fiber [IENF] density). In Experiment 1 TPM was able to prevent OHP effects on Na + VOC: OHP treatment induced a highly significant reduction of the sensory nerve's threshold, during the superexcitability period (p-value = 0.008), whereas TPM co-administration prevented this effect. In Experiment 2 we verified that TPM was able to prevent not only acute phenomena, but also to completely prevent chronic OIPN. This latter observation was supported by a multimodal approach: in fact, only OHP group showed altered findings compared to CTRL group at a neurophysiological (proximal caudal nerve sensory nerve action potential [SNAP] amplitude, p-value = 0.001; distal caudal nerve SNAP amplitude, p-value<0.001, distal caudal nerve sensory conduction velocity, p-value = 0.04), behavioral (mechanical threshold, p-value 0.003) and neuropatho

La tossicità dei farmaci antitumorali rappresenta una delle principali limitazioni nella pratica clinica. Tra gli effetti collaterali dei farmaci chemioterapici, la neurotossicità periferica è uno dei più invalidanti per i pazienti malati di cancro. Oxaliplatino (OHP), un composto ampiamente usato per il trattamento del carcinoma del colon-retto metastatico, è uno dei farmaci antineoplastici più neurotossici. I pazienti possono sviluppare due forme clinicamente distinte di neuropatia periferica: una forma acuta aggravata dal freddo ed una neuropatia sensoriale distale cronica. A causa della mancanza di efficaci terapie farmacologiche in grado di prevenire e/o alleviare i sintomi neuropatici, la riduzione o l'interruzione della dose di OHP è spesso necessaria. Nonostante approfondite ricerche, la patogenesi della neurotossicità periferica indotta da OHP (OIPN) è ancora in gran parte sconosciuta. In letteratura sono descritti numerosi studi preclinici in vivo, diversi tra loro per la schedula di trattamento con OHP utilizzata, tuttavia la caratterizzazione della neurotossicità periferica è limitata. Infatti, per verificare l'insorgenza della OINP, oltre alla valutazione del dolore neuropatico, dovrebbero essere effettuate analisi neurofisiologiche ed istopatologiche. La disfunzione mitocondriale è stata recentemente suggerita come possibile meccanismo coinvolto nell'insorgenza della neurotossicità periferica indotta dai farmaci chemioterapici. Il primo obiettivo di questo lavoro è stato confrontare tre modelli murini di OIPN pubblicati con il modello murino di OIPN attualmente in uso nel nostro laboratorio, mediante una valutazione multimodale. Inoltre, dato il potenziale ruolo dello stress ossidativo nella patogenesi della neuropatia periferica, è stata analizzata la possibilità che il trattamento con OHP potesse indurre stress ossidativo e disfunzione mitocondriale. I risultati di questo studio indicano che una singola dose di OHP 5 mg/kg somministra, The toxicity of anticancer drugs represents one of the major limitation in their clinical use. Among the side effects of chemotherapy, peripheral neurotoxicity is one of the most disabling for cancer patients. Oxaliplatin (OHP) is one of the most neurotoxic antineoplastic drug widely used for the treatment of metastatic colorectal cancer. Patients undergoing OHP-regimen experience two clinically distinct forms of peripheral neuropathy: an acute cold-enhanced form and a chronic distal sensory neuropathy. Due to the lack of effective pharmacological therapies in preventing and/or alleviating neuropathic symptoms, OHP dose reduction or interruption is often mandatory. Despite extensive investigation, the pathogenesis of OHP-induced peripheral neurotoxicity (OIPN) is still largely unknown. In literature several preclinical in vivo studies, different from each other in schedules of OHP treatment, are described but the characterization of peripheral neurotoxicity is limited. In fact, to verify the OINP onset, in addition to the evaluation of neuropathic pain, neurophysiological and histopathological analyses should be assessed. Mitochondrial dysfunction has recently been suggested as putative mechanisms possibly involved in the onset and development of chemotherapy-induced peripheral neurotoxicity. Mitochondrial dysfunction and associated oxidative stress may result in chronic neuronal energy impairment leading to neuropathic symptoms. The first aim of this study was to compare OIPN mouse models reported in three published studies with OIPN mouse model currently used in our laboratory, using a multimodal assessment. Moreover, given the potential role of oxidative stress in the pathogenesis of peripheral neuropathy, the possibility that OHP treatment could induce oxidative stress and eventually mitochondrial dysfunctions has also been analysed. Taken together, the results of this study indicate that a single dose of OHP 5 mg/kg administrated in tail vein is able to reprodu