Impacts of electroacupuncture on neurological function and protein expressions of apoptosis-related Cyt-C and Caspase-9 in rats with traumatic brain injury

Abstract

To observe the impacts of electroacupuncture (EA) on neurological function, the pathological morphology in brain tissue, apoptosis level and the protein expressions of apoptosis-related cytochrome C (Cyt-C) and cysteine aspartic acid protease-9 (Caspase-9) in the rats with traumatic brain injury (TBI) and explore the potential mechanism of EA in treatment of TBI. A total of 70 clean-grade SD mice were randomized into a blank group (8 rats), a sham-operation group (8 rats), a model group (27 rats) and an EA group (27 rats). In terms of interventions of 3, 7 and 14 days, 3 subgroups were divided in the model group and the EA group successively, 9 rats in each subgroup. The modified Feeney free-fall percussion method was adopted to establish TBI models of rats. In the sham-operation group, only the skull was exposed and drilled and no free-fall percussion was exerted. One day after modeling, EA was given in the rats of EA group at "Shuigou" (GV 26), "Baihui" (GV 20) and "Neiguan" (PC 6) and "Zusanli" (ST 36) on the affected side, with intermittent wave, 2 Hz in frequency, once daily, 10 min each time, for 3, 7 and 14 days successively. Separately, on the day 3, 7 and 14 of intervention, the modified neurological severity scale (mNSS) was used to evaluate the degree of neurological function injury in the rats, HE staining and Nissl staining were to observe the pathological and morphological changes in brain tissue, TUNEL method was to observe the level of apoptosis in brain tissue and immunohistochemistry (IHC) method and Western blot were to determine the protein expressions of Cyt-C and Caspase-9 in brain tissue. Compared with the sham-operation group, on the day 3, 7 and 14 of intervention, mNSS scores were increased obviously in the rats of the model group respectively (P<0.01). Compared with the model group, on the day 3, 7 and 14 of intervention, mNSS scores were reduced in the rats of the EA group respectively (P<0.05). On day 3 of intervention, in brain injury region of the rats in the model group and the EA group, gross tissue necrosis, nuclear fragmentation, consolidation and obvious vacuolar changes, reduced Nissl bodies and scattered arrangement were found. On day 7 and 14 of intervention, in the model group and the EA group, the new connective tissue filling and normal cells were visible and Nissl bodies increased. The overall repair and Nissl body quantity in the EA group were better than the model group. Compared with the sham-operation group, on day 3, 7 and 14 of intervention, the numbers of apoptotic cells were increased obviously in the model group (P<0.01) and they were reduced in the EA group as compared with the model group (P<0.05). Compared with the sham-operation group, on day 3, 7 and 14 of intervention, the protein expressions of Cyt-C and Caspase-9 in damaged brain tissue were all increased obviously in the model group (P<0.01) and they were all reduced in the EA group as compared with the model group successively (P<0.05). Electroacupuncture remarkably improves the condition in the neurological function injury and reduces apoptosis degree in TBI model rats, which is likely related to the down-regulation of the protein expressions of Cyt-C and Caspase-9 in damaged brain tissue and further to bring the impacts on mitochondria mediated apoptosis process.