Toll-Like Receptor 2 Attenuates Traumatic Brain Injury-Induced Neural Stem Cell Proliferation in Dentate Gyrus of Rats

Abstract

It was not clear how and whether neural stem cells (NSCs) responded to toll-like receptor 2 (TLR2) in the inflammatory environment after traumatic brain injury (TBI). The current study investigated the correlation of TLR2 and NSC proliferation in the dentate gyrus (DG) using the TBI model of rats. Immunofluorescence (IF) was used to observe the expression of BrdU, nestin, and TLR2 in the DG in morphology. Proliferating cells in the DG were labelled by thymidine analog 5-bromo-2-deoxyuridine (BrdU). Three-labelled BrdU, nestin, and DAPI was used for the identification of newly generated NSCs. Western blotting and real-time polymerase chain reaction (PCR) were used to observe the expression of TLR2 from the level of protein and mRNA. We observed that BrdU+/nestin+/DAPI+ cells accounted for 84.30%±6.54% among BrdU+ cells; BrdU+ and nestin+ cells in the DG were also TLR2+ cells. BrdU+ cells and the expression of TLR2 (both protein and mRNA levels) both elevated immediately at 6 hours (h), 24 h, 3 days (d), and 7 d posttrauma and peaked in 3 d. Results indicated that TLR2 was expressed on proliferating cells in the DG (NSCs possibly) and there was a potential correlation between increased TLR2 and proliferated NSCs after TBI. Taken together, these findings suggested that TLR2 was involved in endogenous neurogenesis in the DG after TBI.

Panax notoginseng Saponins Stimulates Neurogenesis and Neurological Restoration After Microsphere-Induced Cerebral Embolism in Rats Partially Via mTOR Signaling

“…As an initial response to neurogenesis, it is necessary to enhance endogenous NSC proliferation, which helps to promote the migration, differentiation and survival of newborn neurons. Nestin has been widely recognized as a marker of NSC/NPCs and double-labelled BrdU/Nestin was used for the identification of newly generated NSCs in the DG ( von Bohlen und Halbach, 2011 ; Zhang et al, 2020 ). Therefore, we used BrdU/Nestin to evaluate DG cellular proliferative ability at day 14 post-ME, and the immunofluorescence staining results presented that BrdU/Nestin expression in the DG began to increase after ME, which denoted an activated proliferative characteristic of NSC as a response to cerebral ischemia, and PNS 120 mg/kg administration remarkedly advanced BrdU/Nestin expression, suggesting that PNS could augment the number of NSC populations in the hippocampus.…”

Downregulation of microRNA‐124‐3p promotes subventricular zone neural stem cell activation by enhancing the function of BDNF downstream pathways after traumatic brain injury in adult rats

“…The SVZ tissue for real‐time quantitative PCR and Western blotting was taken by microdissection from tissue approximately 1 mm adjacent to the lateral corner of the lateral ventricle. For immunofluorescence (IF), rats were perfused transcardially with 0.1 M PBS (pH 7.4) followed by a fixative solution containing 4% paraformaldehyde in PBS (pH 7.4) for 2 h. The brain was removed and fixed in the same fixative solution at 4°C for an additional 2 h 24 …”

“…Brain sections (4 μm thick) were deparaffinized with xylene, rehydrated with ethanol, and then subjected to antigen retrieval with citric acid and sodium citrate antigen retrieval solution (pH = 6.0) at 120°C for 100 s. The sections were then successively incubated in hydrogen peroxide for 20 min, 0.3% Triton X-100 in PBS for 10 min, and donkey serum for 45 min to block nonspecific signals at room temperature. Then, the primary antibodies were incubated at 4°C for 20 h. 24 The samples were then incubated with secondary antibodies for 4 h at room temperature. The secondary antibodies were Alexa Flour™ 488 donkey anti-mouse IgG (H+L) (1:500, Catalog no.…”

Toll‐like receptors in pathogenesis of neurodegenerative diseases and their therapeutic potential

“… 32 , 33 TLRs are widely expressed in astrocytes and oligodendrocytes, where the main receptors are TLR2 and TLR3, and TLR2 is one of the most abundant TLRs in the CNS. 32 , 33 , 34 , 35 , 36 …”