The Preliminary Research Of Effects Of Adriamycin On Primary Cultured Rat Dorsal Root Ganglion Neurons

Dorsal root ganglion (DRG) cells are the primary afferent neurons of algaesthesis of trunk and extremities. DRG connects the spinal cord with internal and external environment of the organism. It not only transmits and accommodates sensations but also accepts and conveys nociception of the organism, so it plays an important role in the origination and maintenance of neuropathologic pain.Adriamycin, a broad-spectrum anthracycline antibiotic and anticancer therapeutic agent, has obvious neurotoxic effect and autofluorescence. In the recent years, it was demonstrated that intravenous injection adrinmycin can selective destroy the PNS sensory ganglion, it also cause the DRG cells necrosis but not apoptosis. Also it has highly affinity to the dorsal root ganglion and result in the degeneration of the DRG cells. So it was used in the clinical to treat the neuropathic pain which was named selective chemo-ganglionectomy. However the neurotoxicitive mechanisms of ADM. was not clear, it is controversy.Objective:To investigate the effort of Adriamycin(ADM) on in vitro cultured rat dorsal ganglia(DRG) neurons,observe its role and its mechanism of a preliminary study.Method:Using DMEM/F12 serum medium purification cultured newborn SD rat dorsal ganglion cells, seven days after innoculation culture. The purification rat cells were evaluated according to cell count and neuronal specific enolase(NSE) immunocytochemistry stain. Then DRG neurons were randomly divided into six groups: normal group and five experimental groups. The experimental groups were pretreated with different concentration of ADM(groupA, 0.5mg/L; group B, lmg/L;group C, 2mg/L; group D,5mg/L; group E, 10mg/L) . All the experimental groups were kept cultivating for 4 hours after ADM pretreated. Then morphological feature of apoptosis were oberverd by termimal deoxynucleotidyl transferase-mediated nick end labeling(TUNEL) was used to detect the apoptosis. While MTT metabolic rate, lactate dehydrogenase (LDH) activity, superoxide dismutase (SOD) activity, malondialdehyde (MDA) of the DRG neurons were detected.Results:(1) Cultured dorsal root ganglion cells could survive healthily, The purification rate of neurons was 90% or so.(2) There is statistical difference in the apoptosis rate of DRG nerons between experimental groups and normal group(P<0.05).there was positive correlation between the neurons apoptosis rate and the concentration of ADM.and in the group E, necrosis of the DRG neurons was also observed.(3) There was statistical difference in MTT metabolic rate; LDH activety;SOD activity; content of MDA between normal group and experimental groups. (P<0.05) . It was found that the LDH activity, content of MDA and the MTT metabolic rate were higher than those in the normal groups,however the activity of SOD decreased. And there was positive correlation between the MTT metabolic rate, LDH activity, SOD activity, content of MDA and the concentration of ADM.Conclusion:Our present studies shows that ADM can induce the neurotoxitcity of the DRG neurons, the neurotoxicity include apoptosis an necrosis.also the ADM can increased the MTT metabolic rate, LDH activity, content of MDA and decreased the SOD activity. The oxygen free radical may be one of the neurotoxicitive mechanisms of ADM.