ABSTRACT
Objective To investigate the prevalence of musculoskeletal disorders (MSD) in dentists and to analyze the risk factors of MSD to provide suggestions for preventing and reducing MSD in dentists. Methods Through stratified cluster random sampling, 373 dentists were selected from one Hospital of Stomatolagy and five general hospitals among Three-A hospitals in Wuhan as the research objects. The prevalence of MSD was surveyed using the Nordic musculoskeletal disorders standard questionnaire (NMQ) and Numerical Rating Scale (NRS) of pain measurement, and the risk factors of MSD was analyzed with binary Logistic regression. Results The total MSD annual prevalence rate of dentists was 93.3%, with a prevalence rate in neck, shoulder and back, waist and wrist at 78.3%, 70.0%, 56.0% and 36.2% respectively. Through Binary Logistic regression analysis, it was found that the risk factors associated with neck MSD were work fatigue（χ2=24.00，P=0.000）, neck hunching（χ2=23.55，P=0.000）, and shoulder side lift（χ2=24.52，P=0.000）. The risk factors associated with MSD in shoulder and back were work fatigue（χ2=34.64，P=0.000）, neck twisting（χ2=21.68，P=0.000） and wrist bending（χ2=45.87，P=0.000）. The risk factors associated with waist MSD were age（χ2=29.83，P=0.000）, majors（χ2=16.68，P=0.028）, work fatigue（χ2=21.08，P=0.000）, waist bending（χ2=22.88，P=0.000）. The risk factors associated with wrist MSD were gender（χ2=4.17，P=0.041）, majors（χ2=23.47，P=0.001）, working years（χ2=11.63，P=0.009）, physical activities（χ2=9.14，P=0.028）, number of patient visits per day（χ2=18.41，P=0.000）, bending and twisting（χ2=24.12，P=0.000）, wrist twisting（χ2=34.41，P=0.000）, and prevalence of microscope using（χ2=12.09，P=0.020）, while physical exercise was a protective factor for wrist MSD.The differences of the above-mentioned risk factors were statistically significant (P<0.05). Conclusion The prevalence of MSD in dentists is relatively high, and hospital management should strengthen organizational training to help dentists to realize the importance of adopting correct operating posture, a 5-minute breaks during work, prevent MSD at an early stage.
ABSTRACT
Background Endoplasmic reticulum stress (ERS) specific caspase-12 dependent pathway plays a key role in cell apoptosis,and apoptosis is an important characteristic of diabetic retinal neuron degeneration.Sericin is a potentially effective therapy for retinal neuron apoptosis.However,whether sericin has neuroprotection effects on caspase-12 pathway-associated retinal cells in diabetic retinopathy (DR) process is not unelucidated.Objective This study was to investigate the effects of sericin on the inhibition of retinal neuron apoptosis-associated with ERS specific caspase-12 dependent pathway in diabetic rat.Methods The diabetic models were established by feeding high lipid foods and intraperitoneal injection of streptozotocin for 3 consecutive days in 30 SPF SD rats aged 2-3 months.Twenty-four successful model rats were randomized into sericin-treated group and diabetic model group according to computer number allocation,and another 12 matched rats served as normal control group.The normal saline solution and sericin solution dissolved with normal saline solution 2.4 g/(kg · d) was used for 35 days in gavage method in the diabetic model group and sericin-treated group,respectively.The rats were sacrificed and retinal sections were prepared.TUNEL staining was employed to detect retinal neuron apoptosis.The expressions of glucose regulated protein 78 (GRP78),an ERS marker,and caspase-12 and caspase-3 in retinas in protein and transcription levels were detected by Western blot and reverse transcription PCR,respectively.The use and care of the rats complied with Regulations for the Administration of Affairs Concerning Experimental Animals by State Science and Technology Commission and ARVO Statement.Results Diabetic models were successfully established in 24 of total 30 rats,with the successful rate of 80％.Apoptotic cells were found in the rats of various groups,mostly locating in retinal ganglion cell layer and inner nuclear layer.The apoptotic index (AI) was 0.028 4±0.002 3,0.215 1 ± 0.020 9 and 0.115 0±0.018 1 in the normal control group,diabetic model group and sericin-treated group,respectively,and the AI was significantly lower in the sericin-treated group than that in the diabetic control group (P＜ 0.05).Compared with the diabetic model group,the relative expression levels of GRP78,caspase-12 and caspase-3 proteins in rat retinas were significantly elevated in the sericin-treated group (0.523±0.029 vs.0.924±0.039,1.118 ± 0.051 vs.1.468±0.037,0.315±0.024 vs.0.554±0.032) (all at P＜0.05),and the relative expression levels of GRP78,caspase-12 and caspase-3 mRNA in rat retinas were significantly reduced in the sericin-treated group (0.816± 0.022 vs.1.218±0.033,0.216±0.023 vs.0.407±0.012,0.322±0.022 vs.0.531 ±0.029) (all at P＜0.05).Conclusions Sericin can inhibit ERS-related retinal neuron apoptosis by down-regulating the expressions of GRP78,caspase-12 and caspase-3 in ERS specific caspase-12 dependent pathway in diabetic rats.
ABSTRACT
Background Diabetic retinopathy (DR) is a chronic inflammatory disease,with pathological changes of retinal microvessels.Studies demonstrated that sericin has anti-inflammation and anti-oxidation effects,inferring that sericin might play a protective effect on diabetic microangiopathy.Objective This study was to investigate the effects of sericin on intercellular adhesion molecule-1 (ICAM-1),vascular cell adhesion molecule-1 (VCAM-1) and Cx43 expressions in retina and explore the protection of sericin to retinal microangiopathy in diabetic rats.Methods Forty-eight specific pathogen free male SD rats were randomly divided into normal control group,diabetic model group,sericin-treated group and calcium dobesilate-treated group,with 12 rats for each group.The diabetic models were established by intraperitoneal injection of streptozotocin (STZ) for 3 consecutive days and feeding up with high lipid foods.Normal saline solution,2.4 g/(kg · d) sericin solution and 0.2 g/(kg · d) calcium dobesilate were used by gavage administration in the rats of the diabetic model group,sericin-treated group and calcium dobesilate-treated for 3 months group,respectively.The rats were sacrificed and retinal sections were prepared,and the retinal morphology was examined by hematoxylin-eosin staining.The expressions of ICAM-1,VCAM-1 and Cx43 proteins and mRNA in retinas were detected by Western blot assay and reverse transcription PCR.The use and care of the rats complied with Regulations for the Administration of Affairs Concerning Experimental Animals by State Science and Technology Commission and ARVO statement.Results The retinal structure was normal in the normal control group.The swell and rupture of inter limiting membrane (ILM),scatter vascular endothelial cell nuclei breakthrough ILM and decrease of retinal ganglion cells (RGCs) were displayed in the diabetic model group;while in the sericin-treated group and calcium dobesilate-treated group,the mild thickening of ILM and disorder of retinal cells were obtained.The relative expression levels of ICAM-1 and VCAM-1 were significantly raised and those of Cx43 were reduced in the diabetic model group,sericin-treated group and calcium dobesilate-treated group when compared with the normal control group (all at P＜0.05).Compared with the diabetic model group,the expressions of ICAM-1 and VCAM-1 proteins and mRNA in the sericin-treated group were significantly reduced (ICAM-1 protein:0.834 3±0.032 1 vs.0.918 9±0.042 4;VCAM-Ⅰ protein:0.726 4±0.011 2 vs.1.235 0±0.078 9;ICAM-1 mRNA:0.716 3±0.008 6 vs.0.956 8±0.012 5;VCAM-1 mRNA:0.393 7±0.035 0 vs.0.477 9±0.020 6) and those of Cx43 protein and mRNA were evidently elevated (Cx43 protein:0.133 1 ±0.015 3 vs.0.039 2±0.002 0;Cx43 mRNA:0.676 8 ±0.064 8 vs.0.430 8±0.111 3) (all at P＜0.05).Conclusions Sericin can relieve retinal microangiopathy and protect retina against the pathogenesis and development of DR by down-regulating the expressions of ICAM-1,VCAM-1 and upregulating the expression of Cx43 in retinas of diabetic rats.