Objective:To establish an in vivo model of acute radiation esophagitis in Wistar rats based on a small animal precision radiotherapy platform (SARRP). Methods:Thirty-six Wistar rats were randomly divided into control group, 40, 60 and 75 Gy groups. Based on MRI images, the esophageal target area of rats was outlined and the radiotherapy plan was formulated. The rats were respectively irradiated with 0, 8, 12 and 15 Gy per day for 5 consecutive days. The changes of body weight, food intake, esophageal pathology and magnetic resonance imaging were observed.Results:The body weight of rats in 75 Gy group decreased significantly on the 6th day after irradiation (IR) ( P<0.05). The esophageal tissue of rats in each IR group was thicker than that in control ( F = 14.20, P < 0.05). HE staining showed that the formation rate of radiation-induced esophagitis in 40 Gy and 60 Gy groups were 4/5 and 5/5, respectively, mainly mild. In 75 Gy group, the incidence of radiation-induced esophagitis approached to 5/5, of which 3/5 was severe at 9 d post-IR. The pathological injury scores [ M( Q1, Q3)] of rats in each group were 0, 1.0 (0.5, 2.5), 1.0 (1.0, 2.5) and 4.0 (1.5, 6.0) on the 9th day after IR. There was significant difference between the 75 Gy group and the control group ( H=12.69, P<0.05). After dynamic monitoring of neck MRI images, it was found that the esophageal signal of rats in each IR group increased and widened at 9 d post-irradiation. Conclusions:The animal model of acute radiation-induced esophagitis in rats was successfully established based on a small animal precision radiotherapy platform combined with MRI. 75 Gy was the best irradiation dose and the 9th day was the best observation time point.

Objective: To explore the effects of allogeneic bone marrow mesenchymal stem cells (BMSCs) on polarization of peritoneal macrophages isolated from rats with sepsis induced by endotoxin/lipopolysaccharide (LPS). Methods: (1) BMSCs were isolated, cultured and purified from 5 SD rats with whole bone marrow adherent method. The third passage of cells were collected for morphologic observation, detection of expressions of stem cell surface markers CD29, CD44, CD45, and CD90 with flow cytometer, and identification of osteogenic and adipogenic differentiation. (2) Another 45 SD rats were divided into sham injury group (SI, n=5), LPS control group (LC, n=20), and BMSCs-treated group (BT, n=20) according to the random number table. Rats in groups LC and BT were injected with LPS (5 mg/kg) via tail vein to induce sepsis; rats in group SI were injected with the same amount of normal saline to simulate the damage. At post injury hour (PIH) 1, rats in group BT were given 1 mL BMSCs (2×10⁶/mL) via tail vein injection; rats in another two groups were injected with equal volume of phosphate buffer saline. Five rats in group SI at PIH 24 and in groups LC and BT at PIH 6, 12, 24, and 48 were sacrificed to harvest lung tissue for pathological observation with HE staining. In addition, rats in group SI at PIH 24 and in groups LC and BT at PIH 24 and 48 were simultaneously performed with intraperitoneal injection of low-glucose DMEM. Then peritoneal fluid was harvested to culture peritoneal macrophages. Flow cytometer was used to assess the positive expression of cell makers of macrophages including CD68 (making gate), CD11c, and CD206 in group SI at PIH 24 and in groups LC and BT at PIH 24 and 48. Data were processed with one-way analysis of variance and LSD test. Results: (1) The third passage of cells showed uniform fiber-like shape similar to fibroblasts. These cells showed positive expressions of CD29, CD44, CD90 and weak positive expression of CD45. They were able to differentiate into osteoblasts and adipocytes. These cells were identified as BMSCs. (2) At PIH 24, the structure of pulmonary alveoli of rats in group SI was clear and complete with no congestion or inflammatory cell infiltration. At PIH 6, the structure of pulmonary alveoli of rats in groups LC and BT was clear with a small amount of inflammatory cell infiltration, slight congestion and pulmonary interstitial thickening. At PIH 12, the inflammatory responses in lung tissue of rats in group LC were more severe than those in group BT with a large amount of inflammatory cell infiltration, serious congestion, and obvious pulmonary interstitial thickening. The pathological results of rats in group BT at PIH 12 was consistent with the results at PIH 6. At PIH 24, the pathological results of rats in groups LC and BT were similar to the results at PIH 12. At PIH 48, the structure of pulmonary alveoli tissue of rats in group LC was still severely disrupted, with a large number of inflammatory cell infiltration and congestion in lung tissue, but pulmonary interstitial thickening was slightly alleviated than before. The condition of rats in group BT nearly recovered to that in group SI. (3) At PIH 24, the positive expression rate of CD11c in peritoneal macrophages of rats in group LC [(83±10)%] was close to that in group BT [(87±7)%, P>0.05], and they were both significantly higher than the rate in group SI [(55±12)%, with P values below 0.01]. The positive expression rate of CD11c in peritoneal macrophages of rats in group LC [(59±11)%] at PIH 48 was close to that in group SI at PIH 24 (P>0.05), and they were both significantly higher than the rate in group BT [(20±11)%] at PIH 48 (with P values below 0.01). At PIH 24, the positive expression percentages of CD206 in peritoneal macrophages of rats were similar among the three groups (with P values above 0.05). The positive expression percentage of CD206 in peritoneal macrophages of rats in group SI at PIH 24 was close to that in group BT at PIH 48 (P>0.05), and they were both significantly lower than the percentage in group LC at PIH 48 (with P values below 0.01). Conclusions BMSCs can reduce the pathological inflammatory responses in the lung of rats with sepsis and inhibit peritoneal macrophages from polarizing into M1 phenotype, whereas they can not promote macrophages to polarize into M2 phenotype.

OBJECTIVETo investigate the effect of bone marrow mesenchymal stem cells (BMSCs) on secretion of inflammatory cytokines in macrophages stimulated by lipopolysacharide (LPS).

METHODSRat BMSCs and macrophages were isolated, cultured, and identified. The BMSCs and macrophages, cultured alone or in co-culture, were treated with LPS or PBS or without treatment and tested for interleukin-10 (IL-10) and tumor necrosis factor-α (TNF-α) concentrations in the supernatants at 1, 3, 5, 7, 12, and 24 h after the treatment using enzyme-linked immunosorbent assay.

RESULTSExposure to LPS caused significantly increased IL-10 and TNF-α concentrations in the supernatant of cultured macrophages but not in BMSC culture. Macrophages co-cultured with BMSCs showed significantly lowered IL-10 and TNF-α secretions in response to LPS exposure as compared with the macrophages cultured alone.

CONCLUSIONBMSCs can reduce LPS-induced secretion of inflammatory cytokines by the macrophages to ameliorate inflammatory reactions.

Animals ; Cells, Cultured ; Coculture Techniques ; Enzyme-Linked Immunosorbent Assay ; Inflammation ; Interleukin-10 ; secretion ; Lipopolysaccharides ; Macrophages ; secretion ; Mesenchymal Stromal Cells ; cytology ; Rats ; Tumor Necrosis Factor-alpha ; secretion

BACKGROUND:Subepithelial connective tissue grafts are generally considered as the gold standard for soft tissue augmentation.However,it needs a second surgical site,which will prolong the surgical time and increase patients'pain. OBJECTIVE:To compare the histological and thickness changes of attached gingiva following grafting with different soft tissue substitutes in the labial region of the cuspids. METHODS:In three Beagle dogs,attached gingival augmentation was performed with double-layer allogeneic acellular dermal matrix membrane(AADM),bovine-derived acellular dermal matrices(BADM)combined with concentrated growth factor membrane or BADM combined with collagen sponge.Thickness of attached gingiva was measured before augmentation,and 1,2,3,and 4 months after augmentation.Histological analyses were performed after 4 months. RESULTS AND CONCLUSION:The mean values of attached gingival thickness and attached gingival thickness augmentation were higher in the double-layer AADM group than in the other two groups(all P<0.05)from the 1st to 4th month after surgery.At 1 month after surgery,the attached gingival thickness of the three groups increased significantly and then decreased.At 3 months after surgery,the BADM combined with collagen sponge group and the BADM combined with concentrated growth factor membrane group showed no significant difference in the attached gingival thickness of the graft area compared with that before surgery(P>0.05).At 4 months after surgery,the mean value of attached gingival thickness in the double-layer AADM group was still significantly increased compared with that before surgery(P<0.05).The value of attached gingival thickness was highest in the double-layer AADM group,followed by the BADM combined with collagen sponge group,and the lowest in the BADM combined with concentrated growth factor membrane group at 1-4 months after surgery.Histological analyses revealed that AADM was well integrated with the host gingival tissue,and new fibrous connective tissue and fibroblasts grew into the AADM.But the grafts in the other two groups were absorbed and the augmentation area was remodeled into a structure consistent with the surrounding host tissue.To conclude,AADM is superior to BADM combined with concentrated growth factor and BADM combined with collagen sponge with regard to gingival augmentation.