Effect Of Glycyrrhetinic Acid On Proliferation Of Lens Epithelial Cells

Objective To investigate the inhibition of GA on human LECs proliferation in vitro,and the effects of GA on cyclic adenosine monophosphate and cyclic guanosine monophosphate in lens epithelial cell of proliferation induced by recombinant human epidermal growth factor.Methods Human LECs SR01/04 were cultured and passaged inα-MEM.The 3rd passage cells were divided into five groups.Group A was treated with culture medium,rhEGF and GA.And this group was divided into three(A₁,A₂,A₃) according to the different concentrations of GA(7.5μmol/L,15μmol/L,30μmol/L).Group B was the proliferation group which was treated with culture medium and rhEGF.Group C was the control group which was treated with culture medium.After 24 hours incubation,the cells morphological changes were observed with light microscope,the inhibition of LECs was determined by MTT colorimetric assay,and the changes of intracellular cAMP and cGMP concentration effected by GA were observed by radioimmunoassay techniques.Results1.GA could influence morphological characteristics of LECs significantly,microscopically presented as following:(1) LECs of both Proliferative group and Control group increased.(2) The cell density of experimental group decreased significantly more than Proliferative group.(3) There was no significant difference on cell density and amounts between group A₁ and A₂,the cell density of group A₃ decreased significantly compared to group A₁ and A₂.2.The effects of GA on LECs:(1)The absorbance value(A value) of group C,B and A(A₁,A₂,A₃) were 0.492±0.090,0.799±0.025, 0.649±0.011,0.471±0.020,0.345±0.077 respectively.(2)There was no statistically significant difference between group C and group A₂(P＞0.05).There was statistically significant difference between other groups.(P＜0.01)(3)GA could inhibit the growth of LECs,and the ID₅₀ of GA exposed to LECs for 24 hours was 34.509μmol/L.3.The effects of GA on cyclic adenosine monophosphate was present as following:(1)The concentration of cAMP of LECs in the proliferation group and the control group were 1.079±0.191pmol/mL and 1.783±0.150pmol/mL respectively,with significant difference (P＜0.01).(2)The concentration of cAMP of LECs in group A₁,A₂ and A₃ were 1.406±0.104pmol/mL,1.892±0.223pmol/mL,2.441±0.418pmol/mL respectively,which was significant different compared with the proliferation group(P＜0.01).(3)There was sigificant difference on the concentration of cAMP beteween experimental groups with different concentration of GA(P＜0.01).(4)The difference between Control group and A₁,A₃ separately was significant(P＜0.01).There was no significant difference between the Control group and group A₂(P＞0.05).4.The effects of GA on cyclic adenosine monophosphate was present as following:(1) The concentration of cGMP of LECs in the proliferation group and the control group were 0.175±0.021pmol/mL and 0.118±0.016pmol/mL respectively,with significant difference(P＜0.01).(2) The concentration of cGMP of LECs in group A₁,A₂ and A₃ were 0.136±0.006pmol/mL,0.107±0.005pmol/mL,0.078±0.007pmol/mL respectively,which was significant different compared with the proliferation group(P＜0.01).(3) There was sigificant difference on the concentration of cGMP beteween experimental groups with different concentration of GA(P＜0.01).(4) The difference between Control group and A₁,A₃ separately was significant(P＜0.01).There was no significant difference between the Control group and group A₂(P＞0.05).Conclusion1.rhEGF could increase the proliferation of LECs.2.Based on the evidence of GA could inhibit proliferation of LECs, increased the concentration of cAMP and decreased he concentration of cGMP.It could be interpreted that GA could inhibit proliferation of LECs by means of signal transduction of cAMP and cGMP.3.GA could inhibit proliferation of LECs significantly and in a time-dependent manner.It interpreted that GA could be the effective drug to prevent and cure PCO.