Study On The Relationship Between Neuron Apoptosis And Expression Of NF-κB, TNF-α In Rats' Brain After Traumatic Brain Injury

Background: The neuron death resulting from traumatic brain injury (TBI) can be classified into 3 types: (1)neuron death due to primary injury (physical attack); (2)neuron necrosis due to secondary injury such as hemorrhage, compression, anoxemia and ischemia; (3)neuron apoptosis due to inflammatory factor, cytokine,, excitatory transmitter, Ca²⁺ overload and oxygen radical et al. Since apoptosis plays an important role in neuron death in TBI, the anti-apoptosis therapy may benefit patients of TBI through potential effect of neuron protection. Recently study on inflammatory reaction after TBI disclosed that inflammation in which nucleus factor-κB (NF-κB) plays a key role may relate to neuron apoptosis after TBI. It is believed that NF-κB takes part in the molecule event in TBI, with its exact effect on neuron apoptosis still being under controversial.Methods: 162 Sprague-Dawley rats were assigned randomly to TBI group (n=54), sham control group (n=54) and TBI+ PDTC group (n=54). Except the sham control, rats were subjected to severe brain injury following Feeney's method. In eachgroup animals are sacrificed 6h, 24h, 168h after operation. NF-κB, TNF-α and neuron apoptosis rate are defined by immunohistological method, RT-PCR and TUNEL accordingly.Results: The expression of NF-κB and TNF-α in TBI group are much higher than that in sham control group and TBI+PDTC group both 6h and 24h after operation, which correlates to neuron apoptosis rate positively. And this tendency can be partially blocked by PDTC; the expression of NF-κB and TNF-α in TBI group are lower than before but still higher than that in sham control group and TBI+PDTC group 168h after operation, which negatively correlates to neuron apoptosis rate. And this tendency can be partially blocked by PDTC.Conclusion: We find that neuron apoptosis can be promoted and reduced by NF-κB and TNF-α in early and late stage of TBI accordingly. This different role of NF-κB and TNF-α may be resulted from their participation in different apoptosis regulation path in different stage of TBI.