[Electroacupuncture improves limb motor function by down-regulating cytosolic phospholi-pase A2 and reducing apoptosis of nerve cells in rats with spinal cord injury].

Abstract

Objective: To observe the effect of electroacupuncture（EA） on the expression of cytosolic phospholipase A2 （cPLA2） and apoptosis of nerve cells in rats with spinal cord injury （SCI）, so as to explore its mechanisms underlying improvement of SCI.

Methods: Seventy-two female SD rats were randomly divided into model, EA, antagonist and EA+antagonist groups, with 18 rats in each group and other 18 rats were used as the sham operation （sham） group. The SCI model was established by referring to modified Allen's method with a weight impactor. The hindlimb motor function was assessed by using Basso-Beattie-Bresnahan （BBB） score. Rats of the EA group were subjected to EA stimulation at "Dazhui"（GV14）, "Yaoyangguan"（GV3）, bilateral "Ciliao"（BL32） and "Zusanli"（ST36） for 20 min, once a day for 14 days. Rats of the antagonist group received intravenous injection followed by intraperitoneal injection of arachidonyl trifluoromethyl ketone （AACOCF3, antagonist of cPLA2）, once every other day. Rats of the EA+antagonist group received EA treatment combined with antagonist injection. After the treatment, the rats were sacrificed and the spinal cord tissue was collected for detecting the protein expression of cPLA2, p-cPLA2, Bcl-2, Bax and Caspase-3 by Western blot, and the mRNA expression of cPLA2, Bcl-2, Bax and Caspase-3 using qRT-PCR. The morphological changes of the spinal cord were detected by Nissl staining.

Results: In comparison with the sham group, the BBB score, expression of Bcl-2 protein and mRNA were significantly down-regulated （P<0.01）, whereas the expression levels of Bax, Caspase-3 and p-cPLA2 proteins and mRNAs were considerably up-regulated in the model group （P<0.01）. Compared with the model group, the BBB score, expression levels of Bcl-2 protein and mRNA were significantly up-regulated （P<0.01, P<0.05）, while the expression levels of Bax, Caspase-3 and p-cPLA2 proteins in the EA, antagonist and EA+antagonist groups, Bax and cPLA2 mRNAs in both antagonist and EA+antagonist groups, and Caspase-3 mRNA in the EA+antagonist group were obviously down-regulated （P<0.01, P<0.05）. The effect of EA+antagonist was significantly superior to EA in increasing BBB score and in lowering expression of Bax and cPLA2 mRNAs （P<0.01, P<0.05）. Nissl staining showed reduced number of nerve cells and Nissl bodies, and striped dark blue cells in the model group, which was milder in the EA and antagonist groups, particularly in the EA+antagonist group.

Conclusion: EA may improve the limb motor function of SCI rats, which may be related to its functions in down-regulating the expression of p-cPLA2, Bax and Caspase-3 and up-regulating Bcl-2 to reduce the apoptosis of nerve cells in the regional spinal cord.