Human Adipose-derived Mesenchymal Stem Cells (hAD-MSC) Combined With Repetitive Transcranial Magnetic Stimulation (rTMS) In The Treatment Of Traumatic Brain Injury (TBI)

Background and ObjectiveTraumatic Brain Injury (TBI) is defined as the impairment of brain function or the pathological change caused by external forces, and is a worldwide issue of public health. The therapy that we have currently against TBI is limited in restoring the damaged neural function. It has been validated that the adult brain still possesses the potential to generate new born neurons. But the outcome of endogenous neural restoration is far from satisfied. In the past decades, stem cell replacement therapy has been proved to show great promise on neural damage. Mesenchymal stromal cells is the main source of cells used in replacement therapy due to its easy access, broad distribution and easy ex-vivo expansion MethodsFeeney weight drop model was adopted to make a experimental TBI model. Modifiedneurological severity score (mNSS) was performed to assess behavioral performance in PO1, PO7, PO14, PO28. Sprague-Dawley(SD) male rats weighing210-249g were stratified randomly divided in to4groups due to PO1mNSS:1) TBI gourp;2) TBI+TMS group;3) TBI+hAD-MSC group;4) TBI+TMS+hAD-MSC group. TMS was applied to group2) and goup4) from PO2with discharge voltage of700V, frequency of5Hz,900stimuli in total. hAD-MSCs (5*105) intra-cerebral transplantation was applied to group3) and group4) on PO2. Rats were sequentially sacrificed on PO7, PO14and PO28, and brain specimens were harvested following saline and4%paraformaldehyde intracardiac perfusion. Then brain specimens were fixed in4%paraformaldehyde for2days, embedded in paraffin, serially sectioned and stained with hematoxylin eosin staining and immunohistochemical staining for BrdU, Musashil, NeuN, Caspase-3and Anti-Nuclei Antibody.1) The BrdU and musashil were used to evaluate the neural stem and progenitor cells (NSC and NPC) within the subventricular zone (SVZ) of lateral ventrical (LV). NeuN was used to evaluate perilesional mature neuron survival. Caspase-3was used to evaluate perilesional cell apoptosis. Anti-nuclei antibody was used to track donor hAD-MSCs within TBI rat brains.Micro-PET was used to evaluate PO2, PO5and PO13glucose metabolism of the perilesional region. Results1. TMS can significantly decrease post-TBI mortality rate from PO2(two-way ANOVA, p=0.025); with a decrease in mNSS, TMS tended to improve post-TBI behavioral performance (two-way ANOVA, p=0.104). TMS could significantly reduce post-TBI parenchymal loss (two-way ANOVA, p=0.045) from PO28. TMS tended to improve post-TBI perilesional area metabolism from PO13(two-way ANOVA, p=0.075). It has not been validated whether TMS can promote post-TBI endogenous neurogenesis or inhibit perilesional apoptosis.2. MSC seemed to decrease post-TBI mortality rate from PO2(two-way ANOVA, p=0.800); with a decrease in mNSS, MSC tended to improve post-TBI behavioral performance (two-way ANOVA, p=0.179). MSC tended to reduce post-TBI parenchymal loss (two-way ANOVA, p=0.181) from PO28. MSC tended to improve post-TBI perilesional area metabolism from PO13(two-way ANOVA, p=0.136). It has not been validated whether MSC can promote post-TBI endogenous neurogenesis or inhibit perilesional apoptosis. MSC could significantly increase post-TBI SVZ cell proliferation (two-way ANOVA, p=0.012). It has not been validated whether MSC can promote post-TBI endogenous neurogenesis or inhibit perilesional apoptosis.3. It has not been validated whether TMS and MSC have cross-interactions on TBI treatment.4. Almost all hAD-MSC transplanted distributed along the perilesional region. There were detectable hAD-MSCs within the perilesional region on PO28with anti-nuclei antibody labeling.Conclusion1. hAD-MSCs intra-cerebral transplantation could significantly promote SVZ cell proliferation, and tended to increase perilesional metabolism and decrease parenchymal loss.2. TMS could significantly decrease post-TBI mortality rate and parenchymal loss, and tended to increase perilesional metabolism based on the hypothesis that TMS could modify perilesional blood supply and ameliorate inflammation.3. No cross-interactions between hAD-MSC and TMS were observed. 4. Almost all hAD-MSC transplanted distributed along the perilesional region. There were detectable hAD-MSCs within the perilesional region on PO28with anti-nuclei antibody labeling.