Change Of Choline Compounds In Sodium Selenite-induced Apoptosis Of Rats As Quantitative Analysis By In Vitro 9.4T MR Spectroscopy

AIM: To study liver cell apoptosis because of the toxicity of selenium and observe the alteration of choline compounds using in vitro 9.4T high resolution magnetic resonance spectroscopy.METHODS: Twenty male Wistar rats were randomly divided into 2 groups (n=10). The rats in the treatment group were intraperitoneally injected with sodium selenite (Na2SeO3) at the dose of 20mmol/kg and the control group with distilled water at the dose of 1ml/kg. All rats were sacrificed and the livers were dissected. 1H-MRS data were collected using in vitro 9.4T high resolution magnetic resonance spectrometer (Bruker Avance 400 MHz). Spectra were primarily processed in the frequency domain using XWINNMR (Bruker GmBH) and then analyzed using MestRe-c 4.3. H&E staining and TUNEL staining were employed to detect and confirm the change of liver cells.RESULTS: Good 1H-MR spectra of perchloric acid extract from liver tissue of rats were obtained. The conventional metabolites were detected and assigned. The mean concentration of total choline compounds was 5.07769+0.97348 mmol/L in control group and 3.80511+1.15746 in treatment group and the mean concentration of free choline was 1.07142+0.23048 mmol/L in control group and 0.65404+0.19928 in treatment group. The differences of two groups were statistically significant (p=0.047 and p=0.004, respectively). However, there were no statistical significances if we compared the total concentrations of synthetical choline, including Phosphorylcholine and Glycerophosphorylcholin (p=0.459), between the two groups. The hepatic sinus was wider in treatment group than the control group in the view of 100 times magnification by microscopy. The hepatic cells in treatment group were irregular and their verge was not clear. The roundish cytoplasmic vacuoles increased in both size and number in the treatment group. We observed that the cytoplasm was dyed redder than normal one. Simultaneously, the condensed or diffuse chromatin remained randomly distributed, and the nuclear pores disappeared. Apoptosis of hepatic cells in both groups were confirmed by TUNEL assay. The brown ones were the apoptosis positive.CONCLUSION: High dose selenium compounds can cause the rat liver lesion and induce cell apoptosis in vivo. High resolution 1H-MRS in vitro can detect diversified metabolism. Change trend for different ingredient of choline compounds is not completely the same at early period of apoptosis.