[Reference values for carotid artery intima-media thickness among community adult dwellers in Shenzhen City].

Objective: To establish reference values for carotid intima-media thickness (CIMT) of adult dwellers in Shenzhen City. Methods: The study was conducted based on the Shenzhen heart failure epidemiological survey from 2021 to 2022. In this survey, residents aged 18 years and above in Shenzhen were selected by using a multi-stage stratified random sampling method. General information, cardiovascular disease (CVD) related behavior and carotid ultrasound examination and etc. were collected from the participants. People with CVD factors, a history of atherosclerotic cardiovascular disease, carotid plaque or having no carotid ultrasound examination results were excluded. The parameter regression model based on fractional polynomial was used to establish the reference values of CIMT by age and sex. Results: A total of 2 163 healthy individuals were enrolled in the final analysis, including 576 males (26.6%) and 1 587 females (73.4%). The fractional polynomial regression of the CIMT mean and standard deviation was obtained. For men, the regression was meanCIMT=0.324 7+0.006 9×age and SDCIMT=0.076 9+0.001 2×age. For women, the regression was meanCIMT=0.354 9+0.005 4×age and SDCIMT=0.041 6+0.002 0×age. Conclusion: The age and sex reference values for CIMT of adult people in Shenzhen established in this study could provide the latest reference standards for early screening of subclinical CVD.

[Effect of P311 microspheres-loaded thermosensitive chitosan hydrogel on the wound healing of full-thickness skin defects in rats].

Objective: To explore the effect of P311 microspheres-loaded thermosensitive chitosan hydrogel on the wound healing of full-thickness skin defects in rats. Methods: The method of experimental study was adopted. The polyvinyl alcohol/sodium alginate microspheres (simple microspheres), P311 microspheres, and bovine serum albumin labeled with fluorescein isothiocyanate (FITC-BSA) microspheres were prepared by water-in-oil emulsification, and then their morphology was observed under a light microscope/inverted fluorescence microscope. Chitosan solution was prepared, chitosan solution and ß-glycerol phosphate disodium hydrate were mixed to prepare simple thermosensitive hydrogels, and thermosensitive hydrogels loaded with simple microspheres or P311 microspheres were prepared by adding corresponding substances in simple thermosensitive hydrogels. The morphological changes of the prepared four liquids in the state of tilt was observed at 37 ℃. After being freeze-dried, the micromorphology of the prepared four liquids was observed under a scanning electron microscope. Eighteen 3-4-week-old male Sprague-Dawley rats were divided into normal group without any treatment, dressing group, chitosan group, hydrogel alone group, simple microspheres-loaded hydrogel group, and P311 microspheres-loaded hydrogel group, which were inflicted with one full-thickness skin defect wound on both sides of the back spine and were dealt correspondingly, with 3 rats in each group. Rats with full-thickness skin defects in the five groups were collected, the wound healing was observed on post injury day (PID) 0 (immediately), 5, 10, and 15, and the wound healing rates on PID 5, 10, and 15 were calculated. The wound and wound margin tissue of rats with full-thickness skin defects in the five groups on PID 15 and normal skin tissue in the same site of rats in normal group were collected, hematoxylin and eosin staining was conducted to observe the histological changes, immunohistochemical staining was performed to observe the expressions of CD31 and vascular endothelial growth factor (VEGF), and Western blotting was conducted to detect the protein expressions of CD31 and VEGF. The number of samples was all three. Data were statistically analyzed with one-way analysis of variance, analysis of variance for repeated measurement, and Bonferroni correction. Results: Simple microspheres were spherical, with loose and porous surface. The surfaces of P311 microspheres and FITC-BSA microspheres were smooth without pores, and the FITC-BSA microspheres emitted uniform green fluorescence. The diameters of the three microspheres were basically consistent, being 33.1 to 37.7 µm. Compared with chitosan solution and simple thermosensitive hydrogel, the structures of the two microspheres-loaded hydrogels were more stable in the state of tilt at 37 ℃. The two microspheres-loaded hydrogels had denser network structures than those of chitosan solution and simple thermosensitive hydrogel, and in the cross section of which microspheres with a diameter of about 30 µm could be seen. Within PID 15, the wounds of rats in the five groups were healed to different degrees, and the wound healing of rats in P311 microspheres-loaded hydrogel group was the best. On PID 5, 10, and 15, the wound healing rates of rats in dressing group and chitosan group were (26.6±2.4)%, (38.5±3.1)%, (50.9±1.5)%, (47.6±2.0)%, (58.5±3.6)%, and (66.7±4.1)%, respectively, which were significantly lower than (59.3±4.8)%, (87.6±3.2)%, (97.2±1.0)% in P311 microspheres-loaded hydrogel group (P<0.05 or P<0.01). The wound healing rates of rats in hydrogel alone group on PID 10 and 15, and in simple microspheres-loaded hydrogel group on PID 15 were (76.0±3.3)%, (84.5±3.6)%, and (88.0±2.6)%, respectively, which were significantly lower than those in P311 microspheres-loaded hydrogel group (P<0.05). The epidermis, hair follicles, and sebaceous glands could be seen in the normal skin of rats in normal group, without positive expressions of CD31 or VEGF. The wounds of rats in P311 microspheres-loaded hydrogel group on PID 15 were almost completely epithelialized, with more blood vessels, hair follicles, sebaceous glands, and positive expressions of CD31 and VEGF in the wounds than those of rats with full-thickness skin defects in the other four groups, and more protein expressions of CD31 and VEGF than those of rats in the other five groups. Conclusions: The P311 microspheres-loaded thermosensitive chitosan hydrogel can release the encapsulated drug slowly, prolong the drug action time, and promote wound healing in rats with full-thickness skin defects by promoting wound angiogenesis and re-epithelialization.

[Effects of human erythropoietin on transforming growth factor ß1/Smad3 signal transduction pathway in acute wounds of rats].

Objective: To explore the effects of human erythropoietin (hEPO) on healing related transforming growth factor ß1 (TGF-ß1)/Smad3 signal transduction pathway in acute wounds of rats. Methods: Seventy-two healthy Sprague Dawley rats were divided into normal saline control group, low dose group, middle dose group, and high dose group according to the random number table, with 18 rats in each group, after round acute wounds with diameter of 2.5 cm were inflicted on the back of rats. Rats in the 4 groups had debridement routinely. Wounds of rats in normal saline control group were covered by gauzes infiltrated with 1 mL normal saline, while wounds of rats in low dose group, middle dose group, and high dose group were respectively covered by gauze infiltrated with 1 mL hEPO in doses of 50, 100, and 150 U every day, and then the wounds were bandaged with 6 layers of dry gauze. Dressing change was performed once every day. On treatment day (TD) 3, 7, and 14, 6 rats from each group were taken for general observation and calculation of wound healing rate. Then the wound tissue samples were harvested after the rats were sacrificed for observation of expressions of CD31 and transforming growth factor ß1 (TGF-ß1) with immunohistochemical method. Protein expression of phosphorylated Smad3 of the wound tissue of 3 rats were detected by Western blotting. Data were processed with analysis of variance of factorial design, one-way analysis of variance, least-significant difference test, and Bonferroni correction. Results: (1) On TD 3, obvious exudation and scab were observed in the wounds of rats in the 4 groups. On TD 7, the wounds of rats in low dose group, middle dose group, and high dose group were reduced compared with those in normal saline control group. On TD 14, all wounds of rats in the 4 groups were healed. On TD 7, the wound healing rates of rats in middle dose group and high dose group were significantly higher than the rate in normal saline control group (P<0.01). At the other time points, the wound healing rates of rats in the 4 groups were close (P>0.05). (2) CD31 mainly expressed in blood vessels. Except for those in low dose group on TD 3 and 7 (P>0.05), the expressions of CD31 in wound tissue of rats in low dose group on TD 14 and in middle dose group and high dose group on TD 3, 7, and 14 were significantly higher than those in normal saline control group (P<0.01). Except for those on TD 3 (P>0.05), the expressions of CD31 in wound tissue of rats in middle dose group and high dose group on TD 7 and 14 were significantly higher than those in low dose group (P<0.01). Except for that on TD 3 (P>0.05), the expressions of CD31 in wound tissue of rats in high dose group on TD 7 and 14 were significantly higher than those in middle dose group (P<0.01). (3) Except for that in low dose group on TD 3 (1.9±0.7, P>0.05), the expressions of TGF-ß1 in wound tissue of rats in low dose group on TD 7 and 14 (3.3±1.0, 3.7±0.7), and in middle dose group and high dose group on TD 3, 7, and 14 (3.3±1.0, 3.6±1.0, 3.9±0.9, 3.4±0.7, 3.8±0.8, 4.2±0.4) were significantly higher than those in normal saline control group (1.7±0.5, 2.7±1.0, 3.0±0.9, P<0.01). Except for those on TD 7 (P>0.05), the expressions of TGF-ß1 in wound tissue of rats in middle dose group and high dose group on TD 3 and 14 were significantly higher than those in low dose group (P<0.01). Except for that on TD 14 (P<0.01), the expressions of TGF-ß1 in wound tissue of rats in high dose group on TD 3 and 7 were close to those in middle dose group (P>0.05). (4) Except for those in low dose group on TD 3 and 14 and in middle dose group and high dose group on TD 14 (P>0.05), the protein expressions of phosphorylated Smad3 in wound tissue of rats in the 3 groups at the other time points were significantly higher than those in normal saline control group (P<0.01). Except for those on TD 14 (P>0.05), the protein expressions of phosphorylated Smad3 in wound tissue of rats in middle dose group and high dose group on TD 3 and 7 were significantly higher than those in low dose group (P<0.01). Except for that on TD 14 (P>0.05), the protein expressions of phosphorylated Smad3 in wound tissue of rats in high dose group on TD 3 and 7 were significantly lower than those in middle dose group (P<0.01). Conclusions: Exogenous hEPO can increase the expressions of CD31, TGF-ß1, and phosphorylated Smad3 in acute wounds of rats, promote angiogenesis of wounds, and activate TGF-ß1/Smad3 signal transduction pathway to promote wound healing.