The Effects of Minocycline on Spinal Root Avulsion Injury in Rat Model
- Author:
Tan Yew Chin
;
Sim Sze Kiat
;
Hizal Ghazali Faizul
;
Jafri Malin Abdullah
- Publication Type:Journal Article
- Keywords:
minocycline, avulsion injury, histological study, microglia
- From:Malaysian Journal of Medical Sciences
2017;24(1):31-39
- CountryMalaysia
- Language:English
-
Abstract:
Background: The neuroprotective role of minocycline in the treatment of brachial plexus
injury is controversial.
Objective: To study the neuroprotective effect of minocycline via different routes in adult
Sprague Dawley rats with brachial plexus injury.
Methods: The C7 nerve roots of the animals were avulsed via an anterior extravertebral
approach. Traction force was used to transect the ventral motor nerve roots at the preganglionic
level. Intraperitoneal and intrathecal minocycline (50 mg/kg for the first week and 25 mg/kg for
the second week) were administered to promote motor healing. The spinal cord was harvested six
weeks after the injury, and structural changes following the avulsion injury and pharmacological
intervention were analysed.
Results: Motor neuron death and microglial proliferation were observed after the
administration of minocycline via two different routes (intraperitoneal and intrathecal)
following traumatic avulsion injury of the ventral nerve root. The administration of
intraperitoneal minocycline reduced the microglia count but increased the motor neuron count.
Intrathecal minocycline also reduced the microglial count, with a greater reduction than in the
intraperitoneal group, but it decreased the motor neuron count.
Conclusions: Intraperitoneal minocycline increased motor neuron survival by inhibiting
microglial proliferation following traumatic avulsion injury of the nerve root. The inhibitory
effect was augmented by the use of intrathecal minocycline, in which the targeted drug delivery
method increased the bioavailability of the therapeutic agent. However, motor neuron survival
was impaired at a higher concentration of minocycline via the intrathecal route due to the more
efficient method of drug delivery. Microglial suppression via minocycline can have both beneficial
and damaging effects, with a moderate dose being beneficial as regards motor neuron survival
but a higher dose proving neurotoxic due to impairment of the glial response and Wallerian
degeneration, which is a pre-requisite for regeneration.
- Full text:P020170313557245858774.pdf
