OBJECTIVEThe pathophysiology of beta-thalassemia is the imbalance of the alpha and non-alpha globin chain which leads to a series of clinical symptoms of hemolytic anemia. Scientists continuously try to explore gene-activated drugs to increase the level of non-alpha globin chain or decrease the level of alpha globin chain in the treatment of beta-thalassemia. To probe into the effects on globin-gene expression of meisoindigo (Me) in cultured erythroid cells derived from peripheral blood, so as to provide the theoretical basis for applying Me in the treatment of beta-thalassemia.

METHODSBy using the two-step liquid culture of erythroid progenitor cells and reverse transcription polymerase chain reaction (RT-PCR), and by using alpha mRNA as an inner control, the level of gamma mRNA and beta mRNA in cultured erythroid cells derived from peripheral blood of 11 patients with severe beta-thalassemia and 6 normal volunteers were measured under the effect of different concentration (2.5 micro mol/L, 5 micro mol/L and 10 micro mol/L) of Me.

RESULTS(1) No statistic significance was found in the ratio of beta/alpha mRNA by Me in cultured cells from both normal individuals and beta-thalassemia. (2) Me can significantly increase the ratio of gamma/alpha mRNA and (beta + gamma)/alpha mRNA (that is non-alpha/alpha mRNA) in cultured cells from normal individuals and beta-thalassemia. The ratio of gamma/alpha mRNA was increased 0.31 - 0.45 times and the ratio of non-alpha mRNA/alpha mRNA increased 0.21 - 0.32 times in Me induced cells from normal individuals. No significant result was observed among the different concentrations of Me (2.5 micro mol/L, 5 micro mol/L and 10 micro mol/L) in normal individuals. With the increasing of Me concentrations, the ratios of gamma/alpha mRNA and alpha/alpha mRNA were increased in cultured cells from beta-thalassemia. The ratio of gamma/alpha mRNA was increased 0.33 - 1.17 times and the ratio of non-alpha/alpha mRNA increased 0.25 - 0.89 times in Me induced cells from beta-thalassemia. There was no significant difference between the concentrations of 2.5 micro mol/L and 5 micro mol/L concentration in beta-thalassemia. However, there was significant difference between the concentrations of 10 micro mol/L and the concentrations of 2.5 micro mol/L and 5 micro mol/L in beta-thalassemia. (3) The increase of the ratio of gamma/alpha mRNA and non-alpha/alpha mRNA in beta-thalassemia was higher than that in normal individual with induction by Me with a higher concentration (10 micro mol/L).

CONCLUSIONMe can raise the ratio of gamma/alpha mRNA and non-alpha/alpha mRNA in cultured erythroid cells derived from peripheral blood of both normal individual and beta-thalassemia in the level of transcription, which can improve the imbalance of the alpha and non-alpha globin chain. So Me has a latent value in the therapy of beta-thalassemia.