A dose-effect relationship of Ginkgo biloba extract to nerve regeneration in a rat model

Promising therapeutic use of Baccharis trimera (less.) DC. as a natural hepatoprotective agent against hepatic lesions that are caused by multiple risk factors

ETHNOPHARMACOLOGICAL RELEVANCE

Baccharis trimera (Less.) DC is a perennial subshrub, popularly known as "carqueja," that belongs to the Asteraceae family. Ethnobotanical studies indicate that this species is used for the treatment of diabetes and digestive and liver diseases. However, studies that sought to validate its popular use were conducted using ethanolic extracts of the plant, which does not reflect the ethnomedicinal use of this species in humans.

AIM OF THE STUDY

Non-alcoholic fatty liver disease (NAFLD) is characterized by triglyceride accumulation in the liver that can progress to cirrhosis and hepatocellular carcinoma. Because of the severity of this disease, less toxic and more effective therapeutic agents need to be developed. B. trimera may be a promising therapeutic alternative, but its activity against multiple risk factors for liver disease (e.g., smoking, dyslipidemia, and diabetes mellitus) has not been studied. The present study investigated the effects of an ethnomedicinal form of a B. trimera preparation in a rat model of NAFLD that is associated with multiple risk factors.

MATERIAL AND METHODS

Phytochemical analysis of the ethanolic soluble fraction of B. trimera extract was performed using ultra-performance liquid chromatography coupled to high-resolution mass spectrometry. Streptozotocin was used to induce diabetes in male Wistar rats. The rats received a 0.5% cholesterol-enriched diet and were exposed to cigarette smoke (9 cigarettes/day, 5 days/week, for 4 weeks). In the last 2 weeks, the animals were orally treated with vehicle (negative control group), B. trimera extract (30, 100, and 300 mg/kg), or insulin + simvastatin. One group of rats that was not exposed to these risk factors was also evaluated. Blood was collected for glucose, alanine aminotransferase (ALT), and aspartate aminotransferase (AST) analysis. The liver and feces were collected for lipid quantification. The liver was additionally processed for histopathological analysis.

RESULTS

The model successfully induced NAFLD and increased levels of glucose, AST, and ALT in the negative control group. Treatment with the B. trimera extract (30 and 100 mg/kg) and insulin + simvastatin decreased hepatic and fecal lipids. In contrast to insulin + simvastatin treatment, all three doses of B. trimera effectively reduced AST and ALT levels.

CONCLUSION

B. trimera may be promising as a hepatoprotective agent against hepatic lesions that are caused by multiple risk factors.

Neurotherapeutic effects of Ginkgo biloba extract and its terpene trilactone, ginkgolide B, on sciatic crush injury model: A new evidence

Ginkgo biloba leaves extract (GBE) was subjected to neuroprotective-guided fractionation to produce eleven fractions with different polarities and constituents. The intermediate polar fraction was shown to be terpene trilactones-enriched fraction (TEGBE). Out of this fraction, pure ginkgolide B (G-B) was further purified and identified based on its spectral data. The effects of GBE and TEGBE were evaluated in comparison to that of G-B in the crush sciatic nerve injury rat model. To evaluate the neuroprotective effects, sixty Wistar male rats were randomly allocated into 6 groups: naive, sham, crush + normal saline, and three treatment groups; crush + GBE, crush + TEGBE, and crush + G-B. Treatments were given one hour following injury, and once daily for 14 days. Neurobehavioral tests, histomorphological examinations, and immunohistochemical analysis of the sciatic nerve and the spinal cord were performed at weeks 3 and 6 post-injury. GBE, TEGBE and G-B were shown to enhance the functional and sensory behavioral parameters and to protect the histological and the ultrastructural elements in the sciatic nerve. Additionally, all treatments prevented spinal cord neurons from further deterioration. It was shown that G-B has the most significant potential effects among all treatments with values that were nearly comparable to those of sham and naive groups.

Mast cells improve functional recovery of transected peripheral nerve: A novel preliminary study

BACKGROUND

Employment of regenerative properties of cells at the service of nerve repair has been initiated during recent decades. Effects of local transplantation of bone marrow-derived mast cells on peripheral nerve regeneration were studied using a rat sciatic nerve transection model.

MATERIALS AND METHODS

A 10-mm sciatic nerve defect was bridged using a conduit chitosan-based hybrid conduit filled with BMMCs in BMMC group. In positive control group (Pos), the conduit was filled with phosphate-buffered saline alone. The regenerated nerve fibers were studied within 12 weeks after surgery. In sham-operated group, the sciatic nerve was only exposed and manipulated. In negative control (Neg) a 10-mm sciatic nerve defect was created and the nerve stumps were sutured to the adjacent muscles. The regenerated nerve fibers were studied functionally, biomechanically, histologically and immunohiscochemically.

RESULTS

Functional and biomechanical studies confirmed faster recovery of regenerated axons in BMMCs transplanted animals compared to Pos group (p<0.05). Morphometric indices of the regenerated fibers showed that the number and diameter of the myelinated fibers were significantly higher in BMMCs transplanted animals than in Pos group (p<0.05). In immunohistochemistry, location of reactions to S-100 in BMMCs transplanted animals was clearly more positive than that in Pos group.

CONCLUSIONS

BMMCs transplantation could be considered as a readily accessible source of cells that could improve functional recovery of transected sciatic nerve.

Effect of Ginkgo biloba Extract (EGb-761) on Recovery of Erectile Dysfunction in Bilateral Cavernous Nerve Injury Rat Model

OBJECTIVE

To investigate whether the therapeutic effect of Ginkgo biloba extract (GBE) in a rat model can improve erectile dysfunction after bilateral cavernous nerve injury.

METHODS

Forty-three male Sprague-Dawley rats underwent cavernous nerve crush injury and were randomized into 4 groups, including: vehicle only, high-dose GBE, medium-dose GBE, and low-dose GBE. Eight animals underwent sham operation. Four weeks later, erectile function was assessed by cavernous nerve electrostimulation, and penile tissue was collected for histologic analysis.

RESULTS

Significant recovery of erectile function was observed in the high-dose GBE group in a dose-dependent manner as compared with the vehicle-only group (P <.001). The high-dose GBE group had a significant increase in neurofilament-1 expression (P <.001), preservation of neural nitric oxide synthase nerve fibers of the dorsal penile nerve (P <.05), and increased smooth muscle cell content (P <.001) compared with the vehicle-only group. In addition, high-dose GBE markedly augments the smooth muscle-to-collagen ratio (P <.05) and reduces the apoptotic index.

CONCLUSION

Administration of GBE increases neuron survival and preserves the neural nitric oxide synthase nerve fiber and contents of the corpus cavernosum after bilateral cavernous nerve injury. These implications indicate the beneficial effects of GBE use in the repair of the cavernous nerve and recovery of erectile function after radical prostatectomy.

Ginkgo biloba extract (EGb 761) promotes peripheral nerve regeneration and neovascularization after acellular nerve allografts in a rat model

This study aimed to investigate whether or not ginkgo biloba extract (EGb 761) enhances peripheral nerve regeneration and vascularization after repair using acellular nerve allografts (ANA). Seventy-two Sprague-Dawley rats were randomly divided into three experimental groups: a unilateral 15-mm sciatic nerve defect was created and repaired with an autologous graft (autograft group); the same defect was repaired with an 18 mm ANA with an i.p. injection of normal saline for 10 days (saline group); and in the final group, the same defect was repaired with an 18 mm ANA with an i.p. injection of EGb 761 for 10 days (EGb 761 group). Axon outgrowth and vascularization were evaluated by immunocytochemistry 14 days post-implantation. The expression of genes associated with angiogenesis was analyzed by real-time polymerase chain reaction (PCR) seven days post-implantation. Compared with the saline group, rats in the EGb 761 group significantly increased the number of myelinated fibers and the average diameter of the nerves within the graft. There is no significant difference between the EGb 761 group and the autograft group. The expression of CD34 and NF200 was significantly higher in the EGb 761 group than in the saline group. Additionally, EGb 761 treatment increased the expression of several angiogenesis-related genes, including Vegf, SOX18, Prom 1, and IL-6. In conclusion, ANA repair with EGb 761 treatment demonstrates effects on peripheral nerve regeneration and vascularization that are equal to those of autologous graft repair, and that are superior to ANA repair alone.

Effect of topical dexamethasone in reducing dysfunction after facial nerve crush injury in the rat

OBJECTIVE

To date, the effect of topical steroid after a crush injury to rat facial nerve has rarely been reported on. The aim of this study was to investigate the effects of topical dexamethasone on recovery after a crush injury to the rat facial nerve, by functional, electrophysiological, and morphological evaluation.

MATERIALS AND METHODS

We investigated the effects of topical dexamethasone on recovery after a crush injury to rat facial nerve by functional, electrophysiological and morphological evaluation.

RESULTS

The functional recovery using vibrissae movement was significantly high scores in the experimental group than control group at two and three weeks post-crush. The recovery of the threshold of muscle action potential was significantly lowered in the experimental group compared to the control (p<0.05). However, there was no statistical significance in the nerve conduction velocity. The dexamethasone treatment groups showed a larger axon diameter and thicker myelin sheath than the control group.

CONCLUSION

From our results, topical dexamethasone accelerates recovery of the crush-injured facial nerve.

Valproic acid protection against the brachial plexus root avulsion-induced death of motoneurons in rats

In this study, the role of valproic acid (VPA) in protecting motoneuron after brachial plexus root avulsion was investigated in adult rats. Sixty rats were used in this study, and underwent the brachial plexus root avulsion injury, which was created by using a micro-hemostat forceps to pull out brachial plexus root from the intervertebral foramen. The animals were divided into two groups, VPA group administered with VPA dissolved in drinking water (300 mg/kg) daily, and control group had drinking water every day. The spinal cords (C5-T1) were harvested at day 1, 2, 3, 7, 14, and 28 for immunohistochemistry analysis, TUNEL staining, Nissl staining, and electron microscopy, respectively. The results showed that with VPA administration, the survival of motoneurons was promoted and the cell apoptosis was inhibited. The number of c-Jun and Bcl-2 positive motoneurons was increased immediately after avulsion both in control and VPA group, however, the percent of c-Jun positive motoneurons was decreased and the percent of Bcl-2 positive motoneurons was increased by VPA treatment significantly. Our results indicated that motoneurons were protected by VPA against cell death induced by brachial plexus root avulsion through c-Jun inhibition and Bcl-2 induction.

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

BACKGROUND AND OBJECTIVE

Many 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 METHODS

Prospective 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.

RESULTS

Relative 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.

CONCLUSION

From 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.