title: Sensory perturbations using suture and sutureless repair of transected median nerve in rats.
abstract: The effects of changes to cold, mechanical, and heat thresholds following median nerve transection with repair by sutures (Su) or Rose Bengal adhesion (RA) were compared to sham-operated animals. Both nerve-injured groups showed a transient, ipsilateral hyposensitivity to mechanical and heat stimuli followed by a robust and long-lasting hypersensitivity (6-7 weeks) with gradual recovery towards pre-injury levels by 90 days post-repair. Both tactile and thermal hypersensitivity were seen in the contralateral limb that was similar in onset but differed in magnitude and resolved more rapidly compared to the injured limb. Prior to injury, no animals showed any signs of aversion to cold plate temperatures of 4-16 °C. After injury, animals showed cold allodynia, lasting for 7 weeks in RA-repaired rats before recovering towards pre-injury levels, but were still present at 12 weeks in Su-repaired rats. Additionally, sensory recovery in the RA group was faster compared to the Su group in all behavioural tests. Surprisingly, sham-operated rats showed similar bilateral behavioural changes to all sensory stimuli that were comparable in onset and magnitude to the nerve-injured groups but resolved more quickly compared to nerve-injured rats. These results suggest that nerve repair using a sutureless approach produces an accelerated recovery with reduced sensorimotor disturbances compared to direct suturing. They also describe, for the first time, that unilateral forelimb nerve injury produces mirror-image-like sensory perturbations in the contralateral limb, suggesting that the contralateral side is not a true control for sensory testing. The potential mechanisms involved in this altered behaviour are discussed.
authors.affiliation: a School of Medicine, Western Sydney University , NSW , Australia ;
authors.forename: Sumaiya
authors.initials: S
authors.lastname: Shaikh
authors.affiliation: b School of Science and Health, Western Sydney University , NSW , Australia.
authors.forename: Peter
authors.initials: P
authors.lastname: Shortland
authors.affiliation: b School of Science and Health, Western Sydney University , NSW , Australia.
authors.forename: Antonio
authors.initials: A
authors.lastname: Lauto
authors.affiliation: a School of Medicine, Western Sydney University , NSW , Australia ;
authors.forename: Matthew
authors.initials: M
authors.lastname: Barton
authors.affiliation: a School of Medicine, Western Sydney University , NSW , Australia ;
authors.forename: John W
authors.initials: JW
authors.lastname: Morley
authors.affiliation: a School of Medicine, Western Sydney University , NSW , Australia ;
authors.forename: David A
authors.initials: DA
authors.lastname: Mahns
mesh_terms: D000818:Animals; D003080:Cold Temperature; D004195:Disease Models, Animal; D005260:Female; D007839:Functional Laterality; D020233:Gait Disorders, Neurologic / Q000209:etiology*; D006358:Hot Temperature; D020423:Median Neuropathy / Q000150:complications* / Q000601:surgery*; D010147:Pain Measurement; D017288:Pain Threshold / Q000502:physiology*; D051381:Rats; D020318:Rats, Long-Evans; D000071062:Sutureless Surgical Procedures / Q000379:methods*; D013537:Sutures; D013997:Time Factors
keywords: Bilateral hypersensitivity; Cold allodynia; mechanical allodynia; nerve repair; pain; regeneration