scholarly journals 7,8-Dihydroxiflavone Maintains Retinal Functionality and Protects Various Types of RGCs in Adult Rats with Optic Nerve Transection

2021 ◽  
Vol 22 (21) ◽  
pp. 11815
Author(s):  
Alejandro Gallego-Ortega ◽  
Beatriz Vidal-Villegas ◽  
María Norte-Muñoz ◽  
Manuel Salinas-Navarro ◽  
Marcelino Avilés-Trigueros ◽  
...  
Keyword(s):  
Optic Nerve ◽  
Ex Vivo ◽  
Control Group ◽  
Nerve Transection ◽  
Sprague Dawley ◽  
Neuroprotective Effects ◽  
Adult Rats ◽  
Mixed Response ◽  
Optic Nerve Transection

To analyze the neuroprotective effects of 7,8-Dihydroxyflavone (DHF) in vivo and ex vivo, adult albino Sprague-Dawley rats were given a left intraorbital optic nerve transection (IONT) and were divided in two groups: One was treated daily with intraperitoneal (ip) DHF (5 mg/kg) (n = 24) and the other (n = 18) received ip vehicle (1% DMSO in 0.9% NaCl) from one day before IONT until processing. At 5, 7, 10, 12, 14, and 21 days (d) after IONT, full field electroretinograms (ERG) were recorded from both experimental and one additional naïve-control group (n = 6). Treated rats were analyzed 7 (n = 14), 14 (n = 14) or 21 d (n = 14) after IONT, and the retinas immune stained against Brn3a, Osteopontin (OPN) and the T-box transcription factor T-brain 2 (Tbr2) to identify surviving retinal ganglion cells (RGCs) (Brn3a+), α-like (OPN+), α-OFF like (OPN+Brn3a+) or M4-like/α-ON sustained RGCs (OPN+Tbr+). Naïve and right treated retinas showed normal ERG recordings. Left vehicle-treated retinas showed decreased amplitudes of the scotopic threshold response (pSTR) (as early as 5 d), the rod b-wave, the mixed response and the cone response (as early as 10 d), which did not recover with time. In these retinas, by day 7 the total numbers of Brn3a+RGCs, OPN+RGCs and OPN+Tbr2+RGCs decreased to less than one half and OPN+Brn3a+RGCs decreased to approximately 0.5%, and Brn3a+RGCs showed a progressive loss with time, while OPN+RGCs and OPN+Tbr2+RGCs did not diminish after seven days. Compared to vehicle-treated, the left DHF-treated retinas showed significantly greater amplitudes of the pSTR, normal b-wave values and significantly greater numbers of OPN+RGCs and OPN+Tbr2+RGCs for up to 14 d and of Brn3a+RGCs for up to 21 days. DHF affords significant rescue of Brn3a+RGCs, OPN+RGCs and OPN+Tbr2+RGCs, but not OPN+Brn3a+RGCs, and preserves functional ERG responses after IONT.

scholarly journals How does intraarticular dexmedetomidine injection effect articular cartilage and synovium? An animal study

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Başak Akça ◽  
Aysun Ankay Yılbaş ◽  
Filiz Üzümcügil ◽  
Berkem Büyükakkuş ◽  
Elham Bahador Zırh ◽  
...  
Keyword(s):  
Pain Relief ◽  
Knee Joint ◽  
Animal Study ◽  
Left Knee ◽  
Control Group ◽  
Sprague Dawley ◽  
Adult Rats ◽  
Arthroscopic Knee ◽  
The Right

Abstract Background Intraarticular injections are widely used to provide pain relief after arthroscopic procedures and minimize the use of opioids. Dexmedetomidine has been proven to potentiate pain relief and postpone the demand for the first analgesic drug when it is used intraarticularly following arthroscopic knee procedures. However, the effects of dexmedetomidine on articular structures have not yet been evaluated. Our aim was to determine the effects of intraarticular dexmedetomidine injection on articular structures such as cartilage and synovium. Design Animal study. Methods Twenty adult rats (Sprague-Dawley) were enrolled in the study. Following appropriate aseptic and anesthetic conditions, dexmedetomidine (100 mcg/ml) (0.25 ml) was injected into the right knee joint (the study group) and normal saline solution (0.25 ml) into the left knee joint (the control group) of the rats. Four rats were sacrificed from each group on days 1, 2, 7, 14, and 21, and knee joint samples were obtained. Histologists evaluated the articular and periarticular regions and the synovium using histological sections, and a five-point scale was used to grade the inflammatory changes in a blinded manner. Results The groups were found to be similar in terms of median congestion scores, edema and inflammation scores, subintimal fibrosis, neutrophil activation and cartilage structure at each of the time intervals. Conclusion In our placebo-controlled, in vivo trial, the intraarticular use of dexmedetomidine seemed to be safe with respect to the studied histopathological parameters. However, complementary studies investigating the histopathological effects, analgesic dosage and adverse effects of dexmedetomidine on damaged articular structure models are needed.

Splanchnic sequestration of amino acids in aged rats: in vivo and ex vivo experiments using a model of isolated perfused liver

2008 ◽  
Vol 294 (3) ◽  
pp. R748-R755 ◽  
Author(s):  
M. Jourdan ◽  
L. Cynober ◽  
C. Moinard ◽  
M. C. Blanc ◽  
N. Neveux ◽  
...  
Keyword(s):  
Amino Acids ◽  
Ex Vivo ◽  
High Protein Diet ◽  
High Protein ◽  
Protein Diet ◽  
Aged Rats ◽  
Sprague Dawley ◽  
Adult Rats ◽  
Urea Production

Splanchnic sequestration of amino acids (SSAA) is a process observed during aging that leads to decreased peripheral amino acid (AA) availability. The mechanisms underlying SSAA remain unknown. The aim of the present study was to determine whether a high-protein diet could increase nitrogen retention in aged rats by saturating SSAA and whether SSAA could be explained by dysregulation of hepatic nitrogen metabolism. Adult and aged male Sprague-Dawley rats were housed in individual metabolic cages and fed a normal-protein (17% protein) or high-protein diet (27%) for 2 wk. Nitrogen balance (NB) was calculated daily. On day 14, livers were isolated and perfused for 90 min to study AA and urea fluxes. NB was lower in aged rats fed a normal-protein diet than in adults, but a high-protein diet restored NB to adult levels. Isolated perfused livers from aged rats showed decreased urea production and arginine uptake, together with a release of alanine (vs. uptake in adult rats) and a hepatic accumulation of alanine. The in vivo data suggest that SSAA is a saturable process that responds to an increase in dietary protein content. The hepatic metabolism of AA in aged rats is greatly modified, and urea production decreases. This result refutes the hypothesis that SSAA is associated with an increase in AA disposal via urea production.

scholarly journals Rifampicin inhibits neurodegeneration in the optic nerve transection model in vivo and after 1-methyl-4-phenylpyridinium intoxication in vitro

2004 ◽  
Vol 108 (1) ◽  
pp. 65-68 ◽  
Author(s):  
�lkan Kilic ◽  
Ertugrul Kilic ◽  
Paul Lingor ◽  
Burak Yulug ◽  
Mathias B�hr
Keyword(s):  
Optic Nerve ◽  
Nerve Transection ◽  
Optic Nerve Transection

scholarly journals Neuroprotective effects of dexmedetomidine against the ketamine-induced disturbance of proliferation and differentiation of developing neural stem cells in the subventricular zone

2020 ◽  
Author(s):  
Huanhuan Sha ◽  
Peipei Peng ◽  
Bing Li ◽  
Guohua Wei ◽  
Juan Wang ◽  
...  
Keyword(s):  
Stem Cells ◽  
Neural Stem Cells ◽  
Subventricular Zone ◽  
Pediatric Anesthesia ◽  
Brdu Incorporation ◽  
Control Group ◽  
Sprague Dawley ◽  
Neuroprotective Effects ◽  
Proliferation And Differentiation

Abstract Background: Recent years, the number of neonatal patients receiving surgery under general anesthesia is increasing. Previous studies have indicated that ketamine can disturb the proliferation and differentiation of developing neural stem cells (NSCs). Therefore, the safe use of ketamine in pediatric anesthesia has drawn great concern among anesthesiologists and children’s parents. Dexmedetomidine (DEX) is widely used in sedation, antianxiety and analgesia. Recent studies have shown that DEX could provide neuroprotection against anesthetic-induced neurotoxicity in the developing brain. The aim of this in vivo study was to investigate whether DEX had neuroprotective effects on the proliferation and differentiation of NSCs in the subventricular zone (SVZ) following neonatal ketamine exposure. Methods: Postnatal day 7 (PND-7) male Sprague-Dawley rats were equally divided into the following 5 groups: Control group (n=8), ketamine group (n=8), 1 μg/kg DEX+ketamine group (n=8), 5 μg/kg DEX+ketamine group (n=8) and 10 μg/kg DEX+ketamine group (n=8). The proliferation and differentiation of NSCs in the SVZ were assessed by immunostaining with BrdU incorporation. Results: Neonatal ketamine exposure significantly inhibited NSC proliferation and astrocytic differentiation in the SVZ, and neuronal differentiation was markedly promoted. Furthermore, DEX pretreatment reversed the ketamine-induced disturbances in the proliferation and differentiation of NSCs at moderate (5 μg/kg) or high doses (10 μg/kg). Conclusion: Our findings demonstrate that DEX may have neuroprotective effects on NSCs in the SVZ of neonatal rats in a repeated ketamine anesthesia model.

Facilitated migration of cells from a transected peripheral nerve over collagen fibers: in vivo observations

1989 ◽  
Vol 47 ◽  
pp. 888-889
Author(s):  
Arthur J. Wasserman ◽  
Azam Rizvi ◽  
George Zazanis ◽  
Frederick H. Silver
Keyword(s):  
Sciatic Nerve ◽  
Peripheral Nerve ◽  
Collagen Gel ◽  
Collagen Fibers ◽  
Control Group ◽  
Guide Tube ◽  
Sprague Dawley ◽  
Silicone Tube ◽  
Thin Sections

In cases of peripheral nerve damage the gap between proximal and distal stumps can be closed by suturing the ends together, using a nerve graft, or by nerve tubulization. Suturing allows regeneration but does not prevent formation of painful neuromas which adhere to adjacent tissues. Autografts are not reported to be as good as tubulization and require a second surgical site with additional risks and complications. Tubulization involves implanting a nerve guide tube that will provide a stable environment for axon proliferation while simultaneously preventing formation of fibrous scar tissue. Supplementing tubes with a collagen gel or collagen plus extracellular matrix factors is reported to increase axon proliferation when compared to controls. But there is no information regarding the use of collagen fibers to guide nerve cell migration through a tube. This communication reports ultrastructural observations on rat sciatic nerve regeneration through a silicone nerve stent containing crosslinked collagen fibers.Collagen fibers were prepared as described previously. The fibers were threaded through a silicone tube to form a central plug. One cm segments of sciatic nerve were excised from Sprague Dawley rats. A control group of rats received a silicone tube implant without collagen while an experimental group received the silicone tube containing a collagen fiber plug. At 4 and 6 weeks postoperatively, the implants were removed and fixed in 2.5% glutaraldehyde buffered by 0.1 M cacodylate containing 1.5 mM CaCl2 and balanced by 0.1 M sucrose. The explants were post-fixed in 1% OSO4, block stained in 1% uranyl acetate, dehydrated and embedded in Epon. Axons were counted on montages prepared at a total magnification of 1700x. Montages were viewed through a dissecting microscope. Thin sections were sampled from the proximal, middle and distal regions of regenerating sciatic plugs.

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