Protective effect of baicalin-mediated on mice spinal ganglion cells against gentamicin-induced ototoxicity / 中国临床药理学与治疗学

AIM: To study the protective effect of baicalin (BA) against the ototoxicity of gentamicin (GM) of mice spinal ganglion (SG) cells. METHODS: MTT assay was employed to determine the growth inhibition of GM on the SG cells. The activities of superoxide dismutase (T-SOD) and glutathione peroxidase (GSH-PX), and the content of malondialdehyde (MDA) were measured by UV chromatography in SG cells from mice of different groups. RESULTS:Baicalin reversibly limited the GM-induced growth inhibition of SG cells in a dose-dependent manner. BA increased the activity of T-SOD and GM-induced decreased activity of T-SOD and GSH-PX in SG cells. The compound could also reduce MDA level and limite the GM-induced high content of MDA in SG cells. CONCLUSION: Baicalin mediated neuroprotective effect on SG cells is against gentamicin-induced ototoxicity through anti-oxidant.

Electron Microscopic Study on the Development of the Spinal Ganglion of Human Fetus

The development and differentiation of cells in the spinal ganglion were studied by electron microscopy in human fetuses ranging from 12 mm to 260 mm crown rump length. At 12 mm embryo the primitive neuroblasts which had a single process, contained a large numbers of free ribosome and mitochondria but very little rough endoplasmic reticulum. At 30 mm fetus, the primitive spinal ganglion consisted of bipolar neuroblasts, satellite cells and undifferentiated cells. Spindle-shaped bipolar neuroblasts formed spinal ganglion of loosely grouped cells at 50 mm fetus. Two neuroblast cell types, a small cell contained large clumps of rough endoplasmic reticulum at periphery, could be distinguished. At 80 mm fetus, the spinal ganglion constituted of bipolar neuroblast with apparently random distribution of small and large neurons with processes, together with satellite cells and blood vessels. The presences of a large numbers of neurotubules in the Golgi-central region were one of the first sign of further maturation of the neuroblast. During next prenatal stage from 120 mm on fetus, the ganglion cells were large and contained much rough endoplasmic reticulum, neurotubules and extensive Golgi complex. A large number of neuroblasts became transformed into unipolar cells from 180 mm to 260 mm feuts. Nissl bodies appeared during this stage. The ganglion-satellite cell boundary became complicated with increasing age, then enlarging in parallel with the increase in volume of the nerve cell. During next prenatal stage up to 180 mm fetus, the unipolar ganglion cell increased in number and size, and the cytoplsm contained all intracytoplasmic structures which were also found in mature spinal ganglion except for large pigment granules.

THE SOMATO-VISCERAL DIVERGENT PROJECTIONS OF PERIPHERAL PROCESSES OF SUBSTANCE P-CONTAINING SPINAL GANGLIONIC NEURONS——Tri-labeling Study of Combining Fluorescein Tracing / 解剖学报

The chemical nature of spinal ganglionic neurons, the peripheral processes of which project divergently to the somatic and visceral areas, has been identified by means of tri-labeling method of combining fluorescein tracing and immunocytochemistry. Ten rats were used. First, 2?l of 2% fast blue (FB) were injected into the left coeliac ganglion. Two days later, 2% nuclear yellow (NY) was injected into left 9-11th intercostal nerves(l?l for each). On the 4th day, animal was perfused with 10% formalin in 0.1mol/L phosphate buffer.The left Th9-11 spinal ganglia were removed and cut into sections by cryostat. The sections were observed under fluorescence microscope and photographed. The results showed that there were three kinds of neurons in the spinal ganglia: (1) single FB labeled cells with blue fluorescent cytoplasm accounted for 38.8% of total labeled cells; (2) single NY labeled cells with yellow fluorescent nuclei accounted for 52,7%; (3) FB and NY double labeled cells accounted for 8.5% and mostly were small or medium in size. Then, the double labeled cells-containing sections were further processed by substance P-demonstrating PAP immunocytochemical staining. The immunostain and fluorescent photographs in the same section were compared and identified each other. We have found that the labeling ratio of SP/NY was 1.4%; SP/FB was 7% and SP/NY+FB was 28.8%. Present study has not only identified the convergence of somato-vesceral sensation in spinal ganglia but also detected the chemical nature of these neurons(substance P) for the first time. In addition, this result has provided a morphological basis for the mechanisma of referred pain and somato-visceral reflection.

ORIGIN OF SUBSTANCE P-IMMUNOREACTIVE NERVE FIBERS IN THE WALL OF THE HEART / 解剖学报

We Injecte(?) 12-16 ?l 20—40% HRP in normal sanne into the myocardium orthe anterior wall of the left ventricle in six rats and 10 ?l choleragenoid-horsera-dish peroxidase conjugate(CB-HRP)in three rats.The Th1-3 DRG and the nodoseganglia of both side were removed.The sections of these ganglia were proceeded bythe TMB chromogentic reaction for HRP and immunohistochemical reaction(the firstantibody is the substance P antiserum).There are three types of labeled cells——theHRP labeled cells.Sp-IR cells,and HRP-Sp-IR double labeled cells were observedin the Th1-3 DRG and nodose ganglia of both side.The parts of Sp-IR nerve fib-ers in the heart wall originate from the DRG and nodose ganglia and these neuronsprojecting the HRP-Sp-IR nerve fiber contained substanse P.Their functions may berelated to the pain(nociceptive)sensation of the heart.This study may also be aevidence of the main function of the cardiac sympathetic afferent fiber is the con-duction of the pain sensation.A few of HRP-Sp-IR double labeled cells in thenodose ganglion observed suggest that the cardiac parasympathetic afferent fibermay participate in conduction of the pain sensation.This question requires furtherstudy.