The Expression Of TrKA In Microglia In The Situation Of Hypoxia And The Effect Of Catalpol

Objective: To investigate the expression of TrKA in microglia in the situation ofhypoxia and the effect of Catalpol.Methods: BV2was cultured in the situation of hypoxia with or without Catalpol.Immunofluorescence staining, flow cytometry and Western-blot were performed todetect the expression of TrKA on microglia. The green fluorescence labeled by FITCrepresented TrKA positive cells in immunofluorescence staining. The percentageobtained from flow cytometry was expressed as the proportion of TrKA positive cells.The expressions of TrKA and pTrKA with Western-blot were indicated with grayvalues (gray value was proportional with the expression of protein).Results:1. TrKA protein mainly located on the membrane of microglia in the normalsituation. When the microglia was cultured in hypoxia respectively for1.5h and14h,the intensity of TrKA immune-positive fluorescence increased firstly, then decreasedsubsequently. Catalpol could increase the intensity of TrKA immune-positivefluorescence when microglia was cultured in hypoxia both for1.5h and14h.2. The percentage of TrKA positive cells was82.20±2.34%when microglia wascultured normally, which increased significantly to87.27±0.42%and89.07±2.57%after hypoxic culture1.5h and4h respectively. The percentage of TrKA positive cellssignificantly decreased to77.57±0.96%and73.13±2.37%when microglia wascultured in hypoxia for8h and14h respectively. In addition, the results showed thatCatalpol could significantly increase the percentage of TrKA positive cells whenmicroglia was cultured in hypoxia condition, the values were90.63±1.17%,95.87±0.42%,84.07±2.60%and78.73±0.71%in the situation that microglia was cultured inhypoxia for1.5h,4h,8h and14h respectively. 3. The levels of pTrKA indicated by the grey values were1.94±0.73and4.58±0.44respectively when microglia was cultured in hypoxia for1.5h and4h, which weresignificantly higher than0.94±0.02in the normal group. With the prolongation ofhypoxic time, the levels of pTrKA decreased gradually, the values of pTrKA were0.25±0.03and0.17±0.01respectively when microglia was cultured in hypoxia for8h and14h. The result also showed that Catalpol could significantly increase the level ofpTrKA to2.18±0.57,8.62±0.53,1.15±0.05,1.37±0.24respectively whenmicroglia was cultured in hypoxia for1.5h,4h,8h and14h.Conclusions1. TrKA and pTrKA presented in the membrane of microglia in normal situation.2. The levels of TrkA and pTrKA in the membrane of microglia were associatedwith the hypoxic culture time for microglia. The values of TrKA and pTrKA increasedwhen the time of hypoxia was less than4h. While hypoxia more than4h, the values ofTrkA and pTrKA gradually decreased.3. Catalpol could significantly promote the expressions of TrkA and pTrKA inmicroglia in hypoxia.