Alpha-lipoic acid reduces peridural fibrosis after laminectomy of lumbar vertebrae in rabbits

Impact of sorafenib on epidural fibrosis: An immunohistochemical study

AIM

To determine if sorafenib, an antineoplastic agent, could prevent the development of spinal epidural fibrosis (EF).

METHODS

The study used CD105 and osteopontin antibodies in an immunohistochemical approach to quantify EF that occurred as a consequence of laminectomy in rats. Wistar albino rats (n = 16) were divided into two groups: control (L1-2 level laminectomy only) and sorafenib treatment (L1-2 level laminectomy + topical sorafenib). The animals were euthanatized after 6 wk, and the EF tissues were examined for histopathological changes after immunohistochemical staining. The EF grades were assigned to the tissues, and the treatment and control groups were compared.

RESULTS

The EF thickness, inflammatory cell density, and arachnoid adherences determined by light microscopy were significantly higher in the control group compared to the sorafenib-treated group. Based on fibrosis scores, the extent of EF in the treatment group was significantly lower than in the controls. Immunohistochemical staining for CD105 to identify microvessels revealed that the EF grades based on vessel count were significantly lower in the treatment group. Staining for osteopontin did not show any significant differences between the groups in terms of the extent of EF. The staging of EF based on vascular counts observed after immunohistochemical staining for CD105, but not for osteopontin, was compatible with conventional staging methods. Neither toxic effects on tissues nor systemic side effects were observed with the use of sorafenib.

CONCLUSION

Local administration of sorafenib significantly reduced post-laminectomy EF. Decreased neovascularization in spinal tissue may be due to the sorafenib-induced inhibition of vascular endothelial growth factor.

The Influence of α-Lipoic Acid and Garlic Administration on Biomarkers of Oxidative Stress and Inflammation in Rabbits Exposed to Oxidized Nutrition Oils

We hypothesized that addition of substances with antioxidant activity could decrease the concentrations of biomarkers of oxidative stress and inflammatory process, thus inhibiting nonalcoholic steatohepatitis development. We investigated the influence of α-lipoic acid (ALA) and garlic administration on the development of adverse changes in rabbit liver and serum under oxidative stress conditions induced with HFD from oxidized oils. We determined 8-hydroxy-2′-deoxyguanosine (8OHdG) and malondialdehyde (MDA) in liver homogenates, total oxidant status (TOS), lipid peroxides (LOO) and tumor necrosis factor alpha (TNFα) in blood serum, and TNFα and IL-1α genes expression in liver. The results indicate that the intake of dietary ALA and garlic was significantly associated with decreases of 8OHdG and MDA levels in rabbits' liver tissue as well as TOS and LOO levels in rabbits' serum. Similarly, TNFα and IL-1α gene expressions were suppressed due to ALA and garlic supplementation. The histopathological analysis confirmed that HFD results in liver disorder leading to steatosis. This adverse effect of HFD was ameliorated by the supplementation of ALA and garlic. The obtained results indicate a beneficial effect of ALA and garlic administration by reducing the oxidative stress intensity and the levels of some proinflammatory cytokines in rabbits fed HFD.

Interrater Reliability of the Postoperative Epidural Fibrosis Classification: A Histopathologic Study in the Rat Model

Study Design

Agreement study.

Purpose

To validate the interrater reliability of the histopathological classification of the post-laminectomy epidural fibrosis in an animal model.

Overview of Literature

Epidural fibrosis is a common cause of failed back surgery syndrome. Many animal experiments have been developed to investigate the prevention of epidural fibrosis. One of the common outcome measurements is the epidural fibrous adherence grading, but the classification has not yet been validated.

Methods

Five identical sets of histopathological digital files of L5-L6 laminectomized adult Sprague-Dawley rats, representing various degrees of postoperative epidural fibrous adherence were randomized and evaluated by five independent assessors masked to the study processes. Epidural fibrosis was rated as grade 0 (no fibrosis), grade 1 (thin fibrous band), grade 2 (continuous fibrous adherence for less than two-thirds of the laminectomy area), or grade 3 (large fibrotic tissue for more than two-thirds of the laminectomy area). A statistical analysis was performed.

Results

Four hundred slides were independently evaluated by each assessor. The percent agreement and intraclass correlation coefficient (ICC) between each pair of assessors varied from 73.5% to 81.3% and from 0.81 to 0.86, respectively. The overall ICC was 0.83 (95% confidence interval, 0.81-0.86).

Conclusions

The postoperative epidural fibrosis classification showed almost perfect agreement among the assessors. This classification can be used in research involving the histopathology of postoperative epidural fibrosis; for example, for the development of preventions of postoperative epidural fibrosis or treatment in an animal model.

α-Lipoic acid prolongs survival and attenuates acute kidney injury in a rat model of sepsis

Acute kidney injury is a frequent and serious complication in patients with severe sepsis. α-Lipoic acid (ALA), a naturally occurring dithiol compound, has been shown to possess anti-inflammatory and anti-oxidative properties. In the present study we investigated whether ALA could attenuate acute kidney injury and improve survival in a rat model of sepsis. Rats were subjected to caecal ligation and puncture (CLP) to induce sepsis. α-Lipoic acid (200 mg/kg) was administered by oral gavage either immediately (early treatment) or 12 h after the surgical procedure (delayed treatment). Both early and delayed ALA treatment effectively prolonged survival, improved pathological damage in kidney tissues and reduced serum blood urea nitrogen and creatinine levels in CLP-induced septic rats. Furthermore, early treatment with ALA markedly inhibited the release of tumour necrosis factor-α, interleukin (IL)-6 and IL-1β into the serum and reduced mRNA and protein expression of inducible nitric oxide synthase and high mobility group box 1 in kidney tissues from CLP-induced rats. Finally, CLP-induced nuclear factor-κB activation in kidney tissues was significantly suppressed by early ALA treatment. Together, the results indicate that ALA is able to reduce mortality and attenuate acute kidney injury associated with sepsis, possibly by anti-inflammatory actions. α-Lipoic acid may be a promising novel agent for the treatment of conditions associated with septic shock.

Reduction of conjunctival fibrosis after trabeculectomy using topical α-lipoic acid in rabbit eyes

PURPOSE

To evaluate the efficacy of α-lipoic acid (ALA) in reducing scarring after trabeculectomy.

MATERIALS AND METHODS

Eighteen adult New Zealand white rabbits underwent trabeculectomy. During trabeculectomy, thin sponges were placed between the sclera and Tenon's capsule for 3 minutes, saline solution, mitomycin-C (MMC) and ALA was applied to the control group (CG) (n=6 eyes), MMC group (MMCG) (n=6 eyes), and ALA group (ALAG) (n=6 eyes), respectively. After surgery, topical saline and ALA was applied for 28 days to the control and ALAGs, respectively. Filtrating bleb patency was evaluated by using 0.1% trepan blue. Hematoxylin and eosin and Masson trichrome staining for toxicity, total cellularity, and collagen organization; α-smooth muscle actin immunohistochemistry staining performed for myofibroblast phenotype identification.

RESULTS

Clinical evaluation showed that all 6 blebs (100%) of the CG had failed, whereas there were only 2 failures (33%) in the ALAG and no failures in the MMCG on day 28. Histologic evaluation showed significantly lower inflammatory cell infiltration in the ALAGs and CGs than the MMCG. Toxicity change was more significant in the MMCG than the control and ALAGs. Collagen was better organized in the ALAG than control and MMCGs. In immunohistochemistry evaluation, ALA significantly reduced the population of cells expressing α-smooth muscle action.

CONCLUSIONS

ΑLA prevents and/or reduces fibrosis by inhibition of inflammation pathways, revascularization, and accumulation of extracellular matrix. It can be used as an agent for delaying tissue regeneration and for providing a more functional-permanent fistula.

α-Lipoic acid inhibits Helicobacter pylori-induced oncogene expression and hyperproliferation by suppressing the activation of NADPH oxidase in gastric epithelial cells

Hyperproliferation and oncogene expression are observed in the mucosa of Helicobacter pylori- (H. pylori-) infected patients with gastritis or adenocarcinoma. Expression of oncogenes such as β-catenin and c-myc is related to oxidative stress. α-Lipoic acid (α-LA), a naturally occurring thiol compound, acts as an antioxidant and has an anticancer effect. The aim of this study is to investigate the effect of α-LA on H. pylori-induced hyperproliferation and oncogene expression in gastric epithelial AGS cells by determining cell proliferation (viable cell numbers, thymidine incorporation), levels of reactive oxygen species (ROS), NADPH oxidase activation (enzyme activity, subcellular levels of NADPH oxidase subunits), activation of redox-sensitive transcription factors (NF-κB, AP-1), expression of oncogenes (β-catenin, c-myc), and nuclear localization of β-catenin. Furthermore, we examined whether NADPH oxidase mediates oncogene expression and hyperproliferation in H. pylori-infected AGS cells using treatment of diphenyleneiodonium (DPI), an inhibitor of NADPH oxidase. As a result, α-LA inhibited the activation of NADPH oxidase and, thus, reduced ROS production, resulting in inhibition on activation of NF-κB and AP-1, induction of oncogenes, nuclear translocation of β-catenin, and hyperproliferation in H. pylori-infected AGS cells. DPI inhibited H. pylori-induced activation of NF-κB and AP-1, oncogene expression and hyperproliferation by reducing ROS levels in AGS cells. In conclusion, we propose that inhibiting NADPH oxidase by α-LA could prevent oncogene expression and hyperproliferation occurring in H. pylori-infected gastric epithelial cells.

Plasma membranes as heat stress sensors: from lipid-controlled molecular switches to therapeutic applications

The classic heat shock (stress) response (HSR) was originally attributed to protein denaturation. However, heat shock protein (Hsp) induction occurs in many circumstances where no protein denaturation is observed. Recently considerable evidence has been accumulated to the favor of the "Membrane Sensor Hypothesis" which predicts that the level of Hsps can be changed as a result of alterations to the plasma membrane. This is especially pertinent to mild heat shock, such as occurs in fever. In this condition the sensitivity of many transient receptor potential (TRP) channels is particularly notable. Small temperature stresses can modulate TRP gating significantly and this is influenced by lipids. In addition, stress hormones often modify plasma membrane structure and function and thus initiate a cascade of events, which may affect HSR. The major transactivator heat shock factor-1 integrates the signals originating from the plasma membrane and orchestrates the expression of individual heat shock genes. We describe how these observations can be tested at the molecular level, for example, with the use of membrane perturbers and through computational calculations. An important fact which now starts to be addressed is that membranes are not homogeneous nor do all cells react identically. Lipidomics and cell profiling are beginning to address the above two points. Finally, we observe that a deregulated HSR is found in a large number of important diseases where more detailed knowledge of the molecular mechanisms involved may offer timely opportunities for clinical interventions and new, innovative drug treatments. This article is part of a Special Issue entitled: Membrane Structure and Function: Relevance in the Cell's Physiology, Pathology and Therapy.