The discovery of the nerve growth factor(NGF),a specific protein material,by Rita Levi-Montalcini and her colleagues(1954)led to the observation that ifNGF is added to the culture medium,sympathetic and sensory neurons grow well inculture,for it is a potent and specific maintenance factor for these two types of neu-rons.Therefore,we chose the superior cervical ganglion(SCG)as a model systemfor nerve tissue culture in order to study the development,differentiation and rege-neration of nervous tissue in vitro.This report presents what we have observed onthe cultures of SCG that have been successfully established in our laboratory bymeans of explant technique.SCG from newborn rats were explanted onto collagen or plasma-coated coverslipsand maintained in Maximow depression slide assemblies at 37℃.The fluid me-dium was replaced twice a week and consisted of 1/3 calf serum,1/3 synthetic medium199 and 1/3 Hanks' BSS,or of equal parts of calf serum and Hanks' BSS,supplementedwith 600 mg% glucose.NGF(a crude extract of mouse salivary gland)was added tothe medium in a proportion of 1:20;for control,no NGF was added to the medium in some cultures.The cultures were examined microscopically every day,Nissl's stai-ned,Bodian's protargol and ammonium silver impregnated preparations were madeperiodically.Time lapse microcinematographic records were also made.We have planted altogether 209 SCG from newborn rats.All of them grew suc-cessfully in culture with NGF or without NGF,but the SCG with NGF grew muchmore rapidly than those without NGF.NGF strongly stimulates the outgrowth ofneurites and maintains the survival of the sympathetic neurons.Neurites grew outindividually or,more frequently,as bundles extending radially toward the peripheryor forming a meshwork.The tips of elongating neurites expanded to form growthcones from which are projected long slender microspikes(filopodia).These microspi-kes continually waved about,extending,and retracting as the growth cone movedover a substratum.The behavior of the growing tip of neurite is best analyzed bytime lapse microcinematography.The Schwann cells emerged from the explant andproliferate to accompany the neurites.These cells,fusiform or filiform in shape,were usually arranged in alignment along the neurites.They could be easily distingui-shed from fihroblasts.Mitosis of Schwann cells had been observed and recorded bytime lapse microcinematography.The bodies of the sympathetic neurons did not mig-rate away from the explant.

[Summary] The HK-2 cells with different culture media were divided into normal glucose group (NG group,5.5 mmol/L D-glucose) ; high glucose group (HG group,30 mmol/L D-glucose) ; mannitol group (MG group,5.5mmol/L D-glucose+24.5 mmol/L mannitol) ; 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] groups (V1-V3 group)which were exposed to medium containing 30 mmol/L D-glucose and different concentrations of 1,25-(OH)2D3 ;Nethyl-cysteim control group (NAC group,30 mmoL/L D-glucose + 1.0 mmol/L N-Nethyl-cysteim) ; and ethanol control group(SG group,30 mmol/L D-glucose+6.86 × 10-2 mol/L ethanol).The level of intracellular reactive oxygen species,mitochondrial membrane potential,activity of total-superoxide dismutase (T-SOD),level of malondialdehyde,expression of UCP2 mRNA and protein in HK-2 cells were detected.Compared with NG group,the mitochondrial membrane potential significantly decreased in HG group (P＜0.01),and the mitochondrial membrane potential in V group was lower than that in HG group(P＜0.01).The activity ofT-SOD in HG group was significantly lower than that in NG group(P＜0.01),while its level of malondialdehyde was significantly higher than that in NG group(P＜0.01).Compared with HG group,the activity of T-SOD in V groups was significantly increased (P＜0.05)and the level of malondialdehyde in these groups significantly decreased (P＜0.01).The mRNA expression of UCP2 in HG group was increased significantly in comparison with NG group (P ＜ 0.05) and the expression in V groups was significantly decreased in comparison with HG group (P＜0.01).The results suggest that 1,25-(OH)2D3 could reduce the mitochondrial membrane potential,the production of reactive oxygen species,and regulate the expression of UCP2 in order to suppress the oxidative stress induced by high glucose.

Objective To investigate the effects of benazepril on urinary excretion of endothelin 1(Et 1) and the level of plasmic Et 1 (PEt) in patients with diabetes mellitus (DM) and diabetic nephropathy(DN).Methods PEt and 24 hours urinary excretion of Et 1 (UEtV) in 54 patients with DM and 39 patients with DN before and after taking benazepril (7.5～12.5mg/d) for two months were measured using radioimmunoassay method.Results PEt and UEtV in patients with DM were significantly higher than in normal control group ( P

The superior cervical ganglia (SCG) were dissected from neonatal rats.Dissoci-ated cell cultures were grown in Eagle's MEM supplemented with 20% calf serumwhich contain nerve growth factor (NGF).The cultures were divided into two groups:laser irradiation group and control.The former was exposed to lower dose of Helium-Neon laser (power:4 milliwatt)5 minutes every two hours.Two groups cultured for 20,22,24 and 28 hoursrespectively.Then the length of neurites of neurons were measured.At 22 hours,RNA and DNA synthesis of neurons labeled by ~3H-uridine and ~3H-thymidine wereobserved.The results showed that lower dose of Helium-Neon laser irradiation not onlypromotes growth of neurite but also enhances RNA synthesis of neurons in culture.However DNA synthesis in neurons does not promote in this experiment.

HK-2 cells cultured in vitro were divided into three groups: normal glucose group ( NG ), high glucose group( HG), and mannitol group(MG). The expression of angiotensin-converting enzyme( ACE ) and ACE2 mRNA in HK-2 cells was detected. The concentration of angiotensin Ⅱ ( Ang Ⅱ ) in the culture medium was detected. The mRNA and protein expression of ACE and ACE2 existed in normal cultured HK-2 ( NG group ). In comparison with NG group, the mRNA and protein expressions of ACE in HG group increased significantly ( P＜0. 01 ), and the expression of ACE2 mRNA decreased significantly( P＜0. 01 ). The level of Ang Ⅱ in HG group was significantly higher than in NG group( P＜0. 05 ). The result show that high glucose may induce ACE expression and inhibit ACE2 expression, then promote synthesis of Ang Ⅱ in proximal tubular cells.

AIM: To investigate the effect of interleukin-13 (IL-13) on cell proliferation and interleukin-6 (IL-6) production in mesangial cells. METHODS: Cell proliferation was tested by MTT method. The protein synthesis of IL-6 in mesangial cells was measured by ELISA. The expression of IL-6 mRNA in mesangial cells was evaluated by RT-PCR. RESULTS: IL-13(1 ?g/L-100 ?g/L) inhibited the proliferation of mesangial cell in a dose-dependent manner. Both mRNA and protein of IL-6 in mesangial cells were increased significantly in the presence of LPS and this increase could be reversed by IL-13 (1?g/L-100?g/L). However, this increase could not be reversed by IL-13 if the dose was lower than 0.1?g/L and if the mesangial cells were cultured in 5% FCS RPMI1640. CONCLUSION: IL-13 could inhibit IL-6 expression induced by LPS in mesangial cells . We suggested that IL-13 may be an inhibitory cytokine in the regulation of the mesangial cell proliferaltion and inflammatory reaction in glomerulonephritis.