Fabrication of novel tubular scaffold for tendon repair from chitosan in combination with zinc nanoparticles
Volume 9, Issue 2, Spring 2018, Pages 105-111
Alireza Yousefi, Farshid Sarrafzadeh-Rezaei, Siamak Asri-Rezaei, Amir-Abbas Farshid, Mehdi Behfar
Abstract Chitosan bears numerous properties, such as biocompatibility, biodegradability and non-toxicity making it suitable for use in different biomedical fields. Zinc (Zn) is required for fibroblasts proliferation and collagen synthesis as essential elements of wound healing. Its nanoparticles are well known for their capability to enhance wound healing by cell adhesion and migration improvement through growth factors-mediated mechanisms. Poor blood supply and unique histological characteristics of tendon make its regeneration always slow. Also, adhesion formation between tendon and its surrounding tissues is another problem for neotendon to return to its normal structure and functional activities. In this study, a novel tubular scaffold of zinc oxide (ZnO) nanoparticles loaded chitosan has been fabricated for tendon repair. Experimental complete tenotomy of deep digital flexor tendon in a rabbit model was done and scaffolds were placed in the transected area after two ends suturing. After four and eight weeks, adhesion formation around the tendons and tissue reaction to the scaffolds were evaluated macroscopically. Inflammation, angiogenesis and collagen fibers arrangement were also analyzed in histopathological evaluations. After eight weeks, the scaffolds were absorbed completely, adhesions around the tendon were decreased and there was no sign of significant tissue reaction and/or infection in histopathological analyses. The reduced adhesion formation, improved gliding function and better histopathological characteristics suggest this scaffold application as a potential therapy in treatment of tendon acute injuries.
Thioperamide-induced Antinociception is Mediated through Endogenous Opioid System in the Dentate Gyrus of Adult Rats
Volume 1, Issue 3, December 2010, Pages 166-173
Emad Khalilzadeh, Esmaeal Tamaddonfard, Amir-Abbas Farshid, Amir Erfanparast
Abstract The present study investigated the effects of intra-dentate gyrus microinjection of naloxone (an opioid antagonist) and thioperamide (an antagonist of histamine H3 receptors) in the formalin test in rats. Subcutaneous injection of formalin (50 μl, 2.5 %) in the ventral surface of right hind paw produced a biphasic pattern (first phase: 0-5 min and second phase: 15 - 60 min) of licking/biting and shaking of the injected paw. Intra-dentate gyrus microinjections of thioperamide (2 and 4 μg) significantly (P < 0.05) suppressed the pain responses. Microinjections of naloxone (1, 2 and 4 μg) alone into the dentate gyrus non-significantly increased the intensity of pain. Pretreatment with naloxone (4 μg) significantly (P < 0.05) reversed the antinociceptive effect of thioperamide (4 μg). The results indicated that at the level of the dentate gyrus, blockade of histamine H3 receptors with thioperamide produced an analgesic effect. This thioperamide-induced antinociception may be mediated through the endogenous opioid system.