Preventive effect of Dark Plum Sprayagainstradiation-induced damageto the submandibular gland in rats / 医学研究生学报

Objective At present, modern medicine cannot yet clarifythe mechanism of radiation-induceddamage (RID) to salivary glands and its treatment and protective measures remain in the exploration stage .This study was to explore the mechanism of RIDto the submandibular gland and observe the effect of Dark Plum Spray ( DPS) on the submandibular gland after RID in order to provide some evidence for its further application . Methods Using the random number table , 84 healthy Wistar male rats were divid-ed into a normal, an RID model, and an experimental group ,all fed normally.The rats of the RID model groupwere left untreated , while those of the experimental group were intervened with DPS , tid, after RID.On the 1st, 7th, 14th, and 28th day after irradiation, 7 rats were taken from each group for measurement of the body weight, collection of the saliva , and calculation of the salivary flow rate.The submandibular glands were harvested for determination of the mRNA and protein expressions of autophagy-related Atg5 by RT-PCR and Western blot . Results In the 7th day after irradiation , the average body weight in NG[(239.87±16.50)g] was significantly higher (P<0.05) than UG[(213.84±14.42)g] and EG[(222.71±11.14)g].In the 14th ,28th day after irradiation, the average body weight in UG and EG were significantly lower ( P<0.05) than NG;the average body weight in EG was significantly higher ( P<0.05) than UG.In the 1st , 14th day after irradiation , the salivary flow rate in UG and EG were lower than NG but there were no significantly difference(P>0.05).In the 7th day after irradiation, the salivary flow rate in NG[(49.29±16.90)μL/min] and EG[(50.99±6.79)μL/min] were significantly higher (P<0.05) than UG[(30.13±13.19)μL/min].In the 28th day after irradiation, the salivary flow rate in NG[(69.29±11.32)μL/min] were significantly higher (P<0.05) than UG[(49.26±14.13)μL/min] and EG[(46.56±13.60)μL/min] .In the 1st , 7th and 14th day after irradiation , RT-PCR showed that the expressions of Atg 5 in UG and EG were significantly higher(P<0.05) than NG.In the 1st , 7th and 14th day after irradiation, Western blot showed that the expressions of Atg 5 in UG and EG is on the upper trend than NG;In the 1st , 7th day after irradiation , there were no significantly difference between UG and EG .In the 28th day after irradiation , Western blot showed that the expressions of Atg 5 in UG is on the declining trend than NG . Conclusion The autophagic activity of submandibular gland cells may associated with early radiation -induced injury , and Dark Plum Spray may en-hance the action of theanti-apoptosis cytokine in repairingradiation-induceddamageto the submandibular gland .

The radiation protection role of heparin-SOD conjugate in irradiated mice

ABSTRACT Heparin-SOD conjugate (Hep-SOD) was prepared by modifying Cu,Zn-SOD with heparin. An acute radiation-induced mouse injury model was constructed to study the radiation protection effects of Hep-SOD conjugate. Fifty-six mice were randomly divided into seven groups: (I) normal control group; (II) irradiated control group; (III) positive control group (amifostine group, 300 mg/kg); (IV) SOD group (35000 U/kg); (V) high dosage of Hep-SOD group (70000 U/kg); (VI) medium dosage of Hep-SOD group (35000 U/kg); (VII) low dosage of Hep-SOD group (17500 U/kg). Drugs were intraperitoneally injected into each mouse 1 h before radiation except for the normal control group. All the irradiated groups were irradiated with 6 Gy. Organ indices, haematopoietic function indices, peripheral blood cells, liver function test, oxidative stress state and pathological observation were detected to study the effects of Hep-SOD on irradiated mice. Results showed that bone marrow suppression of irradiated mice could be reduced when treated by Hep-SOD before radiation. Oxidative stress detection and pathological observation of the liver and intestine showed that the damage caused by radiation was relieved when mice were treated with Hep-SOD before radiation. This study shows a new direction to prevent organisms from the damage caused by radiation.

Response of EDAG knockout mice to low-dose radiation-induced damage / 军事医学

Objective To generate the erythroid differentiation associated gene(EDAG) knockout mice and analyze their sensitivity to low dose radiation-induced damage.Methods Zinc finger nuclease technology ( ZFNs ) was used to produce the EDAG knockout mice.The low dose radiation-induced damage was evaluated by peripheral blood cell counts, DNA damage and colony formation of bone marrow cells.Wild-type and EDAG knockout mice were irradiated with 0.31 Gy/min X-ray, one minute per day for seven consecutive days, and the cumulative radiation dose was 2.17 Gy(n=7).The blood cell counts were measured by an automated hemocytometer.DNA damage was detected by immunofluorescence assay with a DNA damage marker p-H2A.x antibody (n=3).The colony formation ability of bone marrow cells was evaluated with a semi-solid culture medium(n=3).Results A model of EDAG knockout mice was established.Compared to wide type mice, white blood cell counts of EDAG knockout mice decreased significantly while the DNA damage marker p-H2A.x expression was increased on the third day after X-ray irradiation.The ability of colony-forming was reduced after 7 days of X-ray irradiation.Conclusion Our present study found that EDAG knockout mice are more sensitive to low dose radiation-induced damage as shown by decreased peripheral blood cells counts, reduced colony-forming ability of bone marrow cells, and increased DNA damage.These results suggest that EDAG knockout mice can serve as a powerful tool for evaluation of the biological effects of low-dose radiation damage.

Human salivary gland stem cells ameliorate hyposalivation of radiation-damaged rat salivary glands

Salivary function in mammals may be defective for various reasons, such as aging, Sjogren's syndrome or radiation therapy in head and neck cancer patients. Recently, tissue-specific stem cell therapy has attracted public attention as a next-generation therapeutic reagent. In the present study, we isolated tissue-specific stem cells from the human submandibular salivary gland (hSGSCs). To efficiently isolate and amplify hSGSCs in large amounts, we developed a culture system (lasting 4-5 weeks) without any selection. After five passages, we obtained adherent cells that expressed mesenchymal stem cell surface antigen markers, such as CD44, CD49f, CD90 and CD105, but not the hematopoietic stem cell markers, CD34 and CD45, and that were able to undergo adipogenic, osteogenic and chondrogenic differentiation. In addition, hSGSCs were differentiated into amylase-expressing cells by using a two-step differentiation method. Transplantation of hSGSCs to radiation-damaged rat salivary glands rescued hyposalivation and body weight loss, restored acinar and duct cell structure, and decreased the amount of apoptotic cells. These data suggest that the isolated hSGSCs, which may have characteristics of mesenchymal-like stem cells, could be used as a cell therapy agent for the damaged salivary gland.