Proportion changes of GABAergic neurons in spinal dorsal horn of SNI rats

CHEN Zhao-hui; LIU Hong; LIU Yang

doi:10.3969/j.issn.1002-266X.2015.47.004

Abstract：Objective To observe the proportion changes of γ-aminobutyric acid ( GABA) ergic neurons in spinal dorsal horn (SDH) of SNI (spared nerve injury) model rats.Methods Thirty-six healthy male SD rats were randomly di-vided into two groups:SNI group (group S, n=18) and sham operation group (group D, n=18).The left sciatic nerve trunk and three branches were exposed , two of which , known as tibial and peroneal nerve , were ligated and cut off , and the sural nerve was preserved to build the SNI model in the group S .The left sciatic nerve trunk and three branches were only exposed in the group D.On the 1st day before surgery, 7th, 14th and 28th days after surgery, the outside and inside MWTs (mechanical withdrawal threshold ) of left hind paw in rats were tested.On the 7th , 14th and 28th days after sur-gery, rats in the two groups underwent cardiac perfusion of 4%paraformaldehyde, then the L5 spinal segments were dissec-ted to prepare paraffin sections .GABAergic neurons were labeled by immunohistochemical staining of GABA neurotransmit -ters in cytoplasm .The quantitative analysis of stereological morphometry was used to describe the proportions of GABAergic neurons in the two groups .Results The proportions of GABAergic neurons in the left spinal dorsal horn of group S on the 7th, 14th and 28th days after surgery were 60.41%±8.49%, 55.27%±6.80% and 61.87%±8.12%, respectively, and in the right spinal dorsal horn of group S were 61.94%±11.04%, 64.68%±9.77%and 62.58%±4.25%.On the same way, the proportions of GABAergic neurons in the left spinal dorsal horn of group D on the 7th, 14th and 28th days after surgery were 61.27%±8.73%, 63.59%±5.97% and 62.81%±10.26%, respectively, and in the right spinal dorsal horn of group D were 58.02%±4.58%, 60.84%±8.28%and 63.74%±10.88%.Compared with the right SDH of the same group and left SDH of group D , there were statistically significant reductions in the proportions of GABAergic neurons of the left SDH on 14th day after SNI in the group S (all P<0.05).Conclusion SNI model may lead to the de-crease of the proportions of GABAergic neurons in SDH of damaged side , but this change does not last long .The transfor-mation of GABAergic neurons may be related to mechanical hypersensitivity.