title: Nanowired Delivery of Growth Hormone Attenuates Pathophysiology of Spinal Cord Injury and Enhances Insulin-Like Growth Factor-1 Concentration in the Plasma and the Spinal Cord.
abstract: Previous studies from our laboratory showed that topical application of growth hormone (GH) induced neuroprotection 5 h after spinal cord injury (SCI) in a rat model. Since nanodelivery of drugs exerts superior neuroprotective effects, a possibility exists that nanodelivery of GH will induce long-term neuroprotection after a focal SCI. SCI induces GH deficiency that is coupled with insulin-like growth factor-1 (IGF-1) reduction in the plasma. Thus, an exogenous supplement of GH in SCI may enhance the IGF-1 levels in the cord and induce neuroprotection. In the present investigation, we delivered TiO2-nanowired growth hormone (NWGH) after a longitudinal incision of the right dorsal horn at the T10-11 segments in anesthetized rats and compared the results with normal GH therapy on IGF-1 and GH contents in the plasma and in the cord in relation to blood-spinal cord barrier (BSCB) disruption, edema formation, and neuronal injuries. Our results showed a progressive decline in IGF-1 and GH contents in the plasma and the T9 and T12 segments of the cord 12 and 24 h after SCI. Marked increase in the BSCB breakdown, as revealed by extravasation of Evans blue and radioiodine, was seen at these time points after SCI in association with edema and neuronal injuries. Administration of NWGH markedly enhanced the IGF-1 levels and GH contents in plasma and cord after SCI, whereas normal GH was unable to enhance IGF-1 or GH levels 12 or 24 h after SCI. Interestingly, NWGH was also able to reduce BSCB disruption, edema formation, and neuronal injuries after trauma. On the other hand, normal GH was ineffective on these parameters at all time points examined. Taken together, our results are the first to demonstrate that NWGH is quite effective in enhancing IGF-1 and GH levels in the cord and plasma that may be crucial in reducing pathophysiology of SCI.
authors.affiliation: "RoNeuro" Institute for Neurological Research and Diagnostic, Cluj-Napoca, Romania.
authors.forename: Dafin F
authors.initials: DF
authors.lastname: Muresanu
authors.forename: Aruna
authors.initials: A
authors.lastname: Sharma
authors.forename: José V
authors.initials: JV
authors.lastname: Lafuente
authors.forename: Ranjana
authors.initials: R
authors.lastname: Patnaik
authors.forename: Z Ryan
authors.initials: ZR
authors.lastname: Tian
authors.forename: Fred
authors.initials: F
authors.lastname: Nyberg
authors.forename: Hari S
authors.initials: HS
authors.lastname: Sharma
mesh_terms: D000287:Administration, Topical; D000818:Animals; D016503:Drug Delivery Systems; D004343:Drug Implants; D004487:Edema / Q000209:etiology / Q000517:prevention & control; D005070:Evans Blue / Q000493:pharmacokinetics; D013006:Growth Hormone / Q000008:administration & dosage / Q000032:analysis / Q000493:pharmacokinetics / Q000627:therapeutic use*; D007260:Infusion Pumps; D060186:Infusions, Spinal; D007334:Insulin-Like Growth Factor I / Q000032:analysis*; D007457:Iodine Radioisotopes / Q000493:pharmacokinetics; D008297:Male; D053770:Nanowires; D009474:Neurons / Q000473:pathology; D018696:Neuroprotective Agents / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000627:therapeutic use*; D010539:Permeability; D051381:Rats; D017207:Rats, Sprague-Dawley; D011994:Recombinant Proteins / Q000008:administration & dosage / Q000032:analysis / Q000493:pharmacokinetics / Q000627:therapeutic use; D013116:Spinal Cord / Q000098:blood supply / Q000737:chemistry / Q000473:pathology; D013119:Spinal Cord Injuries / Q000097:blood / Q000150:complications / Q000188:drug therapy* / Q000503:physiopathology; D013904:Thoracic Vertebrae
chemical_list: D004343:Drug Implants; D007457:Iodine Radioisotopes; D018696:Neuroprotective Agents; D011994:Recombinant Proteins; C548904:insulin-like growth factor-1, rat; D005070:Evans Blue; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone