Intraperitoneal Aminoguanidine Improves Sciatic Nerve Ischemia–Reperfusion Injury in Male Sprague-Dawley Rats

Quercetin postconditioning attenuates gastrocnemius muscle ischemia/reperfusion injury in rats

Quercetin, an antioxidant derived from plants, can play a beneficial role in the protection of various tissues against ischemia-reperfusion injuries (IRI). The purpose of the present research was to investigate the protective effects of quercetin on gastrocnemius muscle ischemia-reperfusion. A total of 80 adult male Wistar rats (weights: 250-300 g) were divided into ten groups (n = 8 per group). We used silk 6.0 surgical thread to create a knit to occlude the femoral artery and vein for 3 hr. The treated groups, which comprised half of each experimental group, received intraperitoneal injections of 150 mg/kg quercetin after the ischemia. Blood flow was subsequently reestablished in the reperfusion phase. The rats were kept in reperfusion for 3, 7, 14, or 28 days after which they were killed with high doses of anesthetic drugs, and the gastrocnemius muscles were removed and fixed. Tissue processing, hematoxylin and eosin and toluidine blue staining, and immunohistochemistry were used to assess tumor necrosis factor-α (TNF-α) and nuclear factor κB (NF-κB) levels. A comparison between treated and untreated ischemic sites showed that on the third day of reperfusion, the severity of edema and NF-κB level decreased significantly; on the 7th day of reperfusion, the severity of edema and the levels of TNF-α and NF-κB decreased significantly; and on the 14th day of reperfusion, all of the parameters showed significant decreases. On the 28th day of reperfusion, there were significantly decreased levels of TNF-α and NF-κB, and decreased mast cell infiltration when compared with the untreated groups. According to the results, administration of quercetin after ischemia could significantly prevent gastrocnemius muscle IRI.

Antioxidant and neuroprotective effects of lycopene and insulin in the hippocampus of streptozotocin-induced diabetic rats

In the present study the antioxidant and neuroprotective effects of insulin and lycopene on passive avoidance memory, total antioxidant capacity (TAC), malondialdehyde activity (MDA) and prevention of apoptosis in the hippocampus streptozotocin-induced diabetic rats were examined. The rats were randomly divided to six experimental groups (n=8 per group): Non-diabetic (controls); diabetic; diabetic treated with lycopene; diabetic treated with insulin; diabetic treated with lycopene and insulin; and normal treated with lycopene. Intraperitoneal injection of single dose (60 mg/kg) streptozotocin (STZ) was used to induce the diabetes rat model. The shuttle box test was used for learning and memory assessment. Rats were then sacrificed and hippocampi tissue isolated from the two hemispheres to determine TAC and MDA. Apoptosis rate was also evaluated by terminal deoxynucleotidyl transferase dUTP nick-end labeling and acridine orange staining assays. The results indicated that lycopene and insulin, solely or in combination, prevented hippocampal neuronal cell death and improved learning and cognition by increasing TAC and decreasing MDA. Collectively, the findings presented herein suggest that insulin and lycopene co-treatment has neuroprotective effect, and ameliorates STZ-induced learning and memory impairment and apoptotic cell death in the hippocampal regions of diabetic rats.

Effects of pomegranate peel extract on histopathology, testosterone levels and sperm of testicular torsion–detorsion induced in adult Wistar rats

Background

In the present study, effects of pomegranate peel extract have been evaluated on decreasing the damage induced by testis torsion.

Methods

In this study, 30 adult Wistar rats were randomly divided into three groups of control, experimental (1) and experimental (2). Control: no ischemia, received vehicle alone, exposed to sham operation. Experimental (1): Received the vehicle alone during ischemia followed by 60 days’ reperfusion. Experimental (2): After performing ischemia reperfusion, 500 mg/kg of pomegranate peel extract has been used for 60 days. Blood samples and sperm samples were collected. Testes were harvested and stained with haematoxylin and eosin to study the structure of seminiferous tubules.

Results

The statistical comparison between sperm count and their viability and testosterone hormone amount showed a significant difference between control and experimental (1) groups and control and experimental (2) groups. The results showed an improvement of morphological condition of seminiferous tubules.

Conclusions

Pomegranate peel extract has revealed desirable changes on the effective parameters in infertility.

Selenium Ameliorate Peripheral Nerve Ischemic-Reperfusion Injury via Decreased TNF-α

Selenium is considered as a trace element that plays antioxidant role in the body. So, the aim of this study was to evaluate the effect of selenium on ameliorating of sciatic nerve ischemia-reperfusion injury. Eighty (80) adult male Wistar rats weighing 250-300 g were used. They were divided into 10 groups (n = 8). Then, femoral vessels were obstructed by using 4/0 silk and splitknot techniques. After 3-h ischemia for all the groups, reperfusion was applied for different periods: 3, 7, 14, and 28 days. In half of each experimental group, 0.2 mg/kg selenium was injected intraperitoneally, coinciding with ischemia. After reperfusion, according to the grouping, rats were killed by using high dose of anesthetic drug and then sciatic nerve was removed and fixed. Then, tissue samples were processed and subsequently stained with hematoxylin-eosin, apoptosis, and immunohistochemistry stains. On the third day of reperfusion, the amount of TNF-α as an inflammatory marker of ischemia-reperfusion acute phase increased. On the seventh day of reperfusion, the amount of NF-кB as an apoptotic index and infiltration of mast cells increased in the tissue as a result of development of inflammation. But, on the 14th day of reperfusion, the amount of NF-кB as an apoptotic index decreased to the lowest amount. On the 28th day of reperfusion, the amount of TNF-α as an inflammatory marker decreased to its lowest level. Prescription of selenium concurrent with development of ischemia can reduce the damage caused by sciatic nerve ischemia-reperfusion.

Coenzyme Q10 protects skeletal muscle from ischemia-reperfusion through the NF-kappa B pathway

Objective:

Coenzyme Q10 (CoQ10) has antioxidant and anti-inflammatory activity. The aim of this study was to investigate the effects of CoQ10 on the inhibition of nuclear factor-kappa B (NF-κB) activation during ischemia-reperfusion (I/R) of skeletal muscle.

Methods:

For ischemia induction, the animals were anesthetized and the external iliac vessels blocked for three hours. CoQ10 or vehicle was given intraperitoneally during ischemia, just before reperfusion. Four groups received 3,7,14 and 28 days’ reperfusion, respectively, after the intraperitoneal injection of CoQ10 and four corresponding groups received vehicle only. After reperfusion, the gastrocnemius muscles were removed, fixed and stained for the analysis of edema and mast cell infiltration.

Results:

Immuno-histochemistry staining was performed for the detection of tumor necrosis factor alpha (TNF-α) and NF-κB. CoQ10-treated groups showed a significant decrease of mast cell infiltration in the gastrocnemius muscle and edema as compared with the corresponding non-treated groups. Also, CoQ10-treated groups showed a significant TNF-α and NF-κB expression decrease when compared to the corresponding non-treated controls. The results of this study showed CoQ10 administration with ischemia decreased interstitial edema, degeneration of muscle fibers and infiltration of mast cells.

Conclusions:

It seems that CoQ10 has inhibitory effects on NF-κB and TNF-α activation.

The Effect of Coumaric Acid on Ischemia-Reperfusion Injury of Sciatic Nerve in Rats

The aim of the study was to determine the effect of coumaric acid on sciatic nerve ischemia/reperfusion (SNI) injury in rats. The rats were randomly divided into four groups: control group (no medication or surgical procedure), SNI group, SNI + coumaric acid (CA) group, and SNI + methylprednisolone (MP) group. Ischemia was achieved by abdominal aorta clamping, and all animals were sacrificed 24 h after ischemia. Harvested sciatic nerve segments were investigated histopathologically and for tissue biochemistry. A significant decrease in MDA, an increase in NRF1 levels, and increase in SOD activity were observed in the groups which received coumaric acid and methylprednisolone when compared to the corresponding untreated group (p < 0.05). Ischemic fiber degeneration significantly reduced in the SNI + CA and SNI + MP groups, especially in the SNI + MP group, compared to the SNI group (p < 0.05). Beta amyloid protein expressions were significantly decreased in the SNI + CA group compared to the SNI group (p < 0.05). Our study revealed that coumaric acid treatment after ischemia/reperfusion in rat sciatic nerves reduced oxidative stress and axonal degeneration. Therefore, coumaric acid may play a role in the treatment of peripheral nerve injuries due to ischemia/reperfusion.

Tang-Tong-Fang Confers Protection against Experimental Diabetic Peripheral Neuropathy by Reducing Inflammation

Tang-tong-fang (TTF) is a Chinese herbal formula that has been shown to be beneficial in diabetic peripheral neuropathy (DPN), a common complication secondary to diabetic microvascular injury. However, the underlying mechanism of protection in nerve ischemia provided by TTF is still unclear. We hypothesized that TTF alleviates DPN via inhibition of ICAM-1 expression. Therefore, we tested the effect of TTF in a previously established DPN model, in which nerve injury was induced by ischemia/reperfusion in streptozotocin-induced diabetic rats. We found that the conduction velocity and amplitude of action potentials of sciatic nerve conduction were reduced in the DPN model group but were rescued by TTF treatment. In addition, TTF treatment also attenuated the effect of DPN on other parameters including histology and ultrastructural changes, expression of ICAM-1, MPO, and TNF-α in rat sciatic nerves, and plasma sICAM-1 and MPO levels. Together, our data suggest that TTF treatment may alleviate DPN via ICAM-1 inhibition.

Selenium effect on ischemia-reperfusion injury of gastrocnemius muscle in adult rats

Selenium is a trace element that has antioxidant and neuroprotective effects. The aim of this study is to investigate the effects of selenium in reducing ischemia-reperfusion injury of the gastrocnemius muscle. In this experimental study, 80 adult male Wistar rats weighing 250-300 g were divided into ten groups (N = 8 per group). Group 1 is control group (without ischemia-reperfusion). Group 2 received 0.2 mg/kg selenium. Group 3 received ischemia + 3 d reperfusion + 0.2 mg/kg selenium, group 4 received ischemia + 3 d reperfusion + 0.2 mg/kg placebo, group 5 received ischemia + 7 d reperfusion + 0.2 mg/kg selenium, group 6 received ischemia + 7 d reperfusion + 0.2 mg/kg placebo, group 7 received ischemia + 14 d reperfusion + 0.2 mg/kg selenium, group 8 received ischemia + 14 d reperfusion + 0.2 mg/kg placebo, group 9 received ischemia + 28 d reperfusion + 0.2 mg/kg selenium and group 10 received ischemia + 3 d reperfusion + 0.2 mg/kg placebo. External iliac artery blocked for 3 h. After reperfusion, rats killed and gastrocnemius muscle removed, fixed, and tissue processing performed. Samples stained with hematoxylin-eosin for edema evaluation, toluidine blue for mast cell infiltration evaluation and immunohistochemistry for detection TNF-alpha and NF-kappa B proteins. Comparison of mast cell infiltration, edema of the interstitial fluid on the tissue, expression of TNF-alpha protein, and expression of NF-kappa B protein in the groups that received selenium with corresponding placebo group showed that selenium can reduce edema, mast cell infiltration, and TNF-alpha expression and inactivated NF-kappa B. The use of selenium simultaneously with creating ischemia can reduce ischemia-reperfusion injury of the gastrocnemius muscle.

Effect of aminoguanidine on sciatic functional index, oxidative stress, and rate of apoptosis in an experimental rat model of ischemia-reperfusion injury

This study was conducted to investigate the potential protective effects of aminoguanidine (AG) on sciatic functional index (SFI), oxidative stress status, and apoptosis index using a rat model of experimental sciatic nerve ischemia-reperfusion injury (I/R). Treatment groups received 150 mg AG/kg body mass, 24 h after the induction of ischemia. After reperfusion for 2, 4, 7, 14, and 28 days, we evaluated measured SFI, plasma antioxidant enzymes, total antioxidant capacity (TAC), malondialdehyde (MDA), and index of apoptosis. SFI was significantly improved on the 7th and 14th day of reperfusion in the AG-treated groups. AG treatment resulted in the significant reduction of MDA levels on the 7th and 14th day of reperfusion. TAC was only increased after 7 days of reperfusion compared with the untreated group. SOD activity was decreased in both the untreated and AG-treated groups by comparison with the control, but did not show a significant change. GPx activity decreased only after 7 days of reperfusion. The maximal rate of apoptosis occurred on the 7th day of reperfusion. Treatment with AG significantly reduced this enhancement. AG exhibits positive effects against sciatic nerve I/R injury, possibly in part because of the protective effects of AG against apoptosis and I/R-induced oxidative stress.

The protective effects of insulin and natural honey against hippocampal cell death in streptozotocin-induced diabetic rats

We investigated the effects of insulin and honey as antioxidants to prevent the hippocampal cell death in streptozotocin-induced diabetic rats. We selected sixty Wister rats (5 groups of 12 animals each), including the control group (C), and four diabetic groups (control (D) and 3 groups treated with insulin (I), honey (H), and insulin plus honey (I + H)). Diabetes was induced by streptozotocin injection (IP, 60 mg/kg). Six weeks after the induction of diabetes, the group I received insulin (3-4 U/kg/day, SC), group H received honey (5 mg/kg/day, IP), and group I + H received a combination of the above at the same dose. Groups C and D received normal saline. Two weeks after treatment, rats were sacrificed and the hippocampus was extracted. Neuronal cell death in the hippocampal region was examined using trypan blue assay, "H & E" staining, and TUNEL assay. Cell viability assessment showed significantly lower number of living cells in group D than in group C. Besides, the mean number of living cells was significantly higher in group I, H, and I + H compared to group D. Therefore, it can be concluded that the treatment of the diabetic rats with insulin, honey, and a combination of insulin and honey can prevent neuronal cell death in different hippocampal areas of the studied samples.

Comparison of the effects of subcutaneous anterior transposition and in situ decompression on the histologic and electrophysiologic properties of the ulnar nerve: an experimental study in a rabbit model

PURPOSE

Although anterior transposition of the ulnar nerve is a commonly performed procedure for treatment of cubital tunnel syndrome, there are concerns that surgical mobilization puts blood supply to the nerve at risk. The purpose of this study was to compare the effects of subcutaneous anterior transposition (SAT) and in situ decompression (ISD) on the ulnar nerve's histologic and electrophysiologic properties in a rabbit model.

METHODS

We assigned 30 male, young adult New Zealand white rabbits to 1 of 3 groups (each group, n = 10). The extensive dissection-SAT group underwent complete neurolysis of the right ulnar nerve from brachial plexus to wrist and a subsequent SAT, the ISD group underwent ISD with 4-cm-long exposure of the ulnar nerve, and the SAT group underwent SAT with 4-cm-long circumferential neurolysis of the ulnar nerve. We killed the animals 7 days after the operation. We assessed electrophysiologic changes by finding the percentage of compound motor action potential of the surgical limb compared with the contralateral limb, and histologic changes by ischemic fiber degeneration.

RESULTS

The extensive dissection-SAT group showed a significantly lower percentage of compound motor action potential and higher grade of ischemic fiber degeneration than the ISD and SAT groups. On the other hand, the percentage of compound motor action potential and the grade of ischemic fiber degeneration were similar between the latter 2 groups without a statistically significant difference.

CONCLUSIONS

This study demonstrated that surgical mobilization of the ulnar nerve during SAT has an effect similar to ISD on the nerve's histologic and electrophysiologic properties at the 7th postoperative day in a rabbit model.

CLINICAL RELEVANCE

In a rabbit model, ISD and SAT appear to affect histologic and electrophysiologic findings of the ulnar nerve equally at postoperative day 7, which suggests that they would have the same relative safety in a clinical setting.