RESUMO
Objective To investigate the influence of bushenhuoxue drug-containing serum on PI3K and Akt signaling pathway in purified retinal ganglion cell (RGCs) in vitro of Sprague-Dawley (SD) rats,and to explore the protective mechanisms of bushenhuoxue recipe on RGCs.Methods At first,bushenhuoxue drug-containing serum was prepared,and the RGCs of SD rats were purified;after the apoptotic model of pressurized and purified RGCs was established successfully in vitro using open pressure control system,RGCs were dealt with 50 g · L-1,100 g · L-1,200 g · L-1 concentration gradient of bushenhuoxue drug-containing serum.Then the subjected cells were divided into normal culture group (N group),control group (C group),50 g · L-1 bushenhuoxue group (50 g · L-1 BSHX group),100 g · L-1 bushenhuoxue group (100 g · L-1 BSHX group),200 g · L-1 bushenhuoxue group (200 g · L-1 BSHX group).Finally,cell apoptotic rate was detected by Annexin V-FITC/PI staining,while real-time quantitative PCR (qRT-PCR) and Western blot were used to detect the mRNA and protein expression of PI3K and Akt in each group respectively.Results The results of qRT-PCR detection showed that PI3K,Akt mRNA expression level in C group (0.04 ±0.01) was decreased compared with N group (1.00 ± 0.04),and the difference was statistically significant (all P＜0.05),while PI3K,Akt mRNA levels in 50 g · L-1,100 g · L-1 and 200 g · L-1 BXHX group (0.18 ±0.01,0.21 ±0.02,0.22 ±0.01,0.36 ±0.01,0.84 ±0.10,1.07 ± 0.17) were increased compared with the C group,and the difference was statistically significant (all P ＜0.05).The Western blot results of each group showed that PI3K,Akt protein expression level in C group was decreased compared with N group,with statistical difference (all P ＜ 0.05),while PI3 K,Akt protein expression levels in 50 g · L-1,100 g · L-1 and 200 g · L-1 BSHX group were increased compared with C group,with staffstical difference (all P ＜ 0.05).Conclusion Bushenhuoxue drug-containing serum may inhibit the RGCs apoptosis induced by pressure,which may be related to the activation of PBK/Akt signal transduction pathway.
RESUMO
Background The early disorder of diabetic retinopathy (DR) is the damage of retinal neural cells induced by high glucose and lack of oxygen.Previous studies show that bushenhuoxue serum can enhance the activity of glutamine synthetase (GS) in Müller cells under hypoxia,and glutamate-mediated retinal excitotoxicity also can be reduced by bushenhuoxue serum intervention.However,whether the concentration of glycine can be increased by bushenhuoxue serum is not clear.Objective This study was to investigate the protective effects of bushenhuoxue serum on retinal ganglion cells (RGCs) under hypoxia.Methods The Sprague Dawley (SD) rat serum containing bushenhuoxue was prepared.The RGCs of newborn SD rats were purified and identified by a twostep immunopanning procedure.After 72 hours,all RGCs were cultured in 96-well plates and divided into four groups:normal control group (cultured in adult SD rats normal serum),bushenhuoxue group (cultured in bushenhuoxue serum),hypoxia group (cultured in 1 mmol/L sodium dithionite); hypoxia + bushenhuoxue intervention group (cultured in bushenhuoxue serum+sodium dithionite).Glutamate and glycine contents in the extracellular fluid were detected by L-8800 automatic amino acid analyzer,and the content of lactate dehydrogenase (LDH) was assayed using LDH kits in 24,48 and 72 hours after culture.Results Cultured cells showed the green fluorescence under the immnofluorescence microscope.The contents of glutamate,glycine and LDH in the extracellular fluid were (0.0805±0.0010)mg/L,(0.0554±0.001 5)mg/L and (1 626.03 ±122.10)μmol/(min · L) in the normal control group in 24 hours after culture,and those in the hypoxia group were (0.022 5±0.001 1) mg/L,(0.014 6±0.001 1)mg/L and (1 458.68±94.23)μμmol/(min · L),showing significant reducing in the hypoxia group (q =-3.53,P =0.00 ; q =-2.45,P =0.00 ; q =-2.98,P =0.02).Compared with the normal control group,LDH and glycine contents in the extracellular fluid were significant raised in the hypoxia group 48 hours after culture (q =2.55,P =0.01 ;q =4.48,P =0.00).Seventy two hours after culture,the glutamate and glycine contents in the hypoxia group were higher than those of the normal control group (q =2.45,P =0.00 ;q =3.72,P =0.00).In 48 and 72 hours of culture,the contents of glycine were (0.017 4±0.001 5) and (0.019 2±0.001 2) mg/L in the hypoxia+bushenhuoxue intervention group,which were significantly higher than (0.016 0±0.001 2) and (0.018 0±0.000 8) mg/L in the hypoxiagroup (q=2.28,P=0.04;q=2.33,P=0.03),but the LDH level were (1 632.94±264.31) and (1 875.00±137.45)μmol/(min · L) in the hypoxia+ bushenhuoxue intervention group,which were lower than (1 688.49 ± 112.86) and (2 267.86 ± 175.21) μmol/(min · L) of the hypoxia group (q =-2.95,P =0.02 ; q =-2.35,P=0.00).No significant differences were seen in the glutamate content 24,48 and 72 hours after culture (P=0.55,0.28,0.46).A positive correlation was seen between the glutamate content and glycine content in the extracellular fluid (Kendall coefficient =0.519,Spearman coefficient =0.696,both at P =0.000).Conclusions The release levels of glutamate and glycine increase in the hypoxia RGCs,which probably is a compensatory response of RGCs.Bushenhuoxue serum can protect RGCs against injury by increasing the release of glycine and decreasing the LDH leakage from RGCs.