Collagen is a major structural protein in the matrix of animal cells and the most widely distributed and abundant functional protein in mammals. Collagen’s good biocompatibility, biodegradability and biological activity make it a very valuable biomaterial. According to the source of collagen, it can be broadly categorized into two types: one is animal collagen; the other is recombinant collagen. Animal collagen is mainly extracted and purified from animal connective tissues by chemical methods, such as acid, alkali and enzyme methods, etc. Recombinant collagen refers to collagen produced by gene splicing technology, where the amino acid sequence is first designed and improved according to one’s own needs, and the gene sequence of improved recombinant collagen is highly consistent with that of human beings, and then the designed gene sequence is cloned into the appropriate vector, and then transferred to the appropriate expression vector. The designed gene sequence is cloned into a suitable vector, and then transferred to a suitable expression system for full expression, and finally the target protein is obtained by extraction and purification technology. Recombinant collagen has excellent histocompatibility and water solubility, can be directly absorbed by the human body and participate in the construction of collagen, remodeling of the extracellular matrix, cell growth, wound healing and site filling, etc., which has demonstrated significant effects, and has become the focus of the development of modern biomedical materials. This paper firstly elaborates the structure, type, and tissue distribution of human collagen, as well as the associated genetic diseases of different types of collagen, then introduces the specific process of producing animal source collagen and recombinant collagen, explains the advantages of recombinant collagen production method, and then introduces the various systems of expressing recombinant collagen, as well as their advantages and disadvantages, and finally briefly introduces the application of animal collagen, focusing on the use of animal collagen in the development of biopharmaceutical materials. In terms of application, it focuses on the use of animal disease models exploring the application effects of recombinant collagen in wound hemostasis, wound repair, corneal therapy, female pelvic floor dysfunction (FPFD), vaginal atrophy (VA) and vaginal dryness, thin endometritis (TE), chronic endometritis (CE), bone tissue regeneration in vivo, cardiovascular diseases, breast cancer (BC) and anti-aging. The mechanism of action of recombinant collagen in the treatment of FPFD and CE was introduced, and the clinical application and curative effect of recombinant collagen in skin burn, skin wound, dermatitis, acne and menopausal urogenital syndrome (GSM) were summarized. From the exploratory studies and clinical applications, it is evident that recombinant collagen has demonstrated surprising effects in the treatment of all types of diseases, such as reducing inflammation, promoting cell proliferation, migration and adhesion, increasing collagen deposition, and remodeling the extracellular matrix. At the end of the review, the challenges faced by recombinant collagen are summarized: to develop new recombinant collagen types and dosage forms, to explore the mechanism of action of recombinant collagen, and to provide an outlook for the future development and application of recombinant collagen.

Electromagnetic fields can regulate the fundamental biological processes involved in bone remodeling. As a non-invasive physical therapy, electromagnetic fields with specific parameters have demonstrated therapeutic effects on bone remodeling diseases, such as fractures and osteoporosis. Electromagnetic fields can be generated by the movement of charged particles or induced by varying currents. Based on whether the strength and direction of the electric field change over time, electromagnetic fields can be classified into static and time-varying fields. The treatment of bone remodeling diseases with static magnetic fields primarily focuses on fractures, often using magnetic splints to immobilize the fracture site while studying the effects of static magnetic fields on bone healing. However, there has been relatively little research on the prevention and treatment of osteoporosis using static magnetic fields. Pulsed electromagnetic fields, a type of time-varying field, have been widely used in clinical studies for treating fractures, osteoporosis, and non-union. However, current clinical applications are limited to low-frequency, and research on the relationship between frequency and biological effects remains insufficient. We believe that different types of electromagnetic fields acting on bone can induce various “secondary physical quantities”, such as magnetism, force, electricity, acoustics, and thermal energy, which can stimulate bone cells either individually or simultaneously. Bone cells possess specific electromagnetic properties, and in a static magnetic field, the presence of a magnetic field gradient can exert a certain magnetism on the bone tissue, leading to observable effects. In a time-varying magnetic field, the charged particles within the bone experience varying Lorentz forces, causing vibrations and generating acoustic effects. Additionally, as the frequency of the time-varying field increases, induced currents or potentials can be generated within the bone, leading to electrical effects. When the frequency and power exceed a certain threshold, electromagnetic energy can be converted into thermal energy, producing thermal effects. In summary, external electromagnetic fields with different characteristics can generate multiple physical quantities within biological tissues, such as magnetic, electric, mechanical, acoustic, and thermal effects. These physical quantities may also interact and couple with each other, stimulating the biological tissues in a combined or composite manner, thereby producing biological effects. This understanding is key to elucidating the electromagnetic mechanisms of how electromagnetic fields influence biological tissues. In the study of electromagnetic fields for bone remodeling diseases, attention should be paid to the biological effects of bone remodeling under different electromagnetic wave characteristics. This includes exploring innovative electromagnetic source technologies applicable to bone remodeling, identifying safe and effective electromagnetic field parameters, and combining basic research with technological invention to develop scientifically grounded, advanced key technologies for innovative electromagnetic treatment devices targeting bone remodeling diseases. In conclusion, electromagnetic fields and multiple physical factors have the potential to prevent and treat bone remodeling diseases, and have significant application prospects.

ObjectiveTo evaluate the efficacy of Shuanghua drink in treating primary dysmenorrhea in the rat model and explore its mechanism of action. MethodsAn oxytocin-induced writhing mouse model was established to evaluate the analgesic effect of Shuanghua drink. Forty-eight non-pregnant female institute of cancer research （ICR） mice were randomly divided into six groups， including a blank group， a model group， an ibuprofen group （85.00 mg·kg^-1）， a low-dose group of Shuanghua drink （7.14 mL·kg^-1）， a medium-dose group of Shuanghua drink （14.28 mL·kg^-1）， and a high-dose group of Shuanghua drink （28.57 mL·kg^-1）. Each group consisted of eight mice. All treatment groups received daily intragastric administration at corresponding doses for 10 consecutive days. One hour after the final administration， 2 U of oxytocin was intraperitoneally injected per mouse. The writhing latency and number of writhing within 20 minutes were recorded. A primary dysmenorrhea rat model was established by using estradiol benzoate and oxytocin to evaluate the inhibitory effect of Shuanghua drink on the contraction of uterine smooth muscle. Forty-eight non-pregnant female Sprague-Dawley （SD） rats were divided into six groups， including a blank group， a model group， an ibuprofen group （51.00 mg·kg^-1）， a low-dose group of Shuanghua drink （4.28 mL·kg^-1）， a medium-dose group of Shuanghua drink （8.57 mL·kg^-1）， and a high-dose group of Shuanghua drink （17.10 mL·kg^-1）. Each group consisted of eight rats. Rats received subcutaneous injections of estradiol benzoate for 10 consecutive days to enhance uterine sensitivity. On the eleventh day， oxytocin （2 U/rat） was intraperitoneally administered to induce abnormal uterine contractions for establishing the primary dysmenorrhea model. All treatment groups received daily intragastric administration from the second day of modeling for 10 days. The effects of Shuanghua drink were evaluated by using parameters including uterine motility and the variation rate of uterine motility. The mechanism of action was investigated in rats with primary dysmenorrhea. The content of prostaglandin F_2α （PGF_2α）， prostaglandin E₂ （PGE₂）， thromboxane B₂ （TXB₂）， prostacyclin metabolite （6-keto-PGF_1α）， and β-endorphin （β-EP） in uterine tissue of rats was detected by using enzyme-linked immunosorbent assay （ELISA）. The changes in the content of nitric oxide （NO） and inducible nitric oxide synthase （iNOS） were analyzed via colorimetric assay. Western blot was performed to determine the content of phosphorylated inhibitor of kappa B kinase beta （p-IKKβ）/IKKβ， phosphorylated inhibitor of kappa B alpha （p-IκBα）， IκBα， phosphorylated p65 （p-p65）， p65， and cyclooxygenase-2 （COX-2） proteins in uterine tissue of rats. ResultsIn the oxytocin-induced writhing mouse model， the model group exhibited significantly shortened writhing latency and increased writhing frequency compared to the control group （P<0.01）. Both the ibuprofen group and the high-dose group of Shuanghua drink displayed prolonged writhing latency （P<0.05）， while the ibuprofen group and the low-dose， medium-dose， and high-dose groups of Shuanghua drink exhibited reduced writhing frequency （P<0.01）. In the primary dysmenorrhea rat model， the uterine motility and its variation rate in the model group were significantly higher than those in the blank group （P<0.01）. These parameters were markedly suppressed by ibuprofen and Shuanghua drink at all tested doses （P<0.01）. For the mechanism of action， the model group showed significantly increased PGF_2α/PGE₂， TXB₂/6-keto-PGF_1α， NO， and iNOS in uterine tissue （P<0.05， P<0.01） and significantly decreased β-EP （P<0.01）. These parameters were significantly attenuated in the ibuprofen group and the low-dose， medium-dose， and high-dose groups of Shuanghua drink. The PGF_2α/PGE₂ （P<0.01）， TXB₂/6-keto-PGF_1α （P<0.01）， NO （medium-dose group P<0.05）， and iNOS （P<0.01） were reduced， and the β-EP （medium-dose group P<0.05） was up-regulated. Compared to the model group， the ibuprofen group and medium-dose group of Shuanghua drink showed significantly increased content of β-EP in the serum of rats （P<0.05）. Compared to the blank group， the model group showed significantly elevated expressions of COX-2， p-IKKβ/IKKβ， p-IκBα/IκBα， and p-p65/p65 proteins （P<0.01） and significantly reduced anti-inflammatory protein IκBα （P<0.05）. Compared to the model group， the ibuprofen group and the low-dose， medium-dose， and high-dose groups of Shuanghua drink showed significantly reduced expressions of COX-2 （P<0.01）， p-IKKβ/IKKβ （P<0.01）， p-IκBα/IκBα （P<0.05， P<0.01）， and p-p65/p65（P<0.01） and up-regulated expression of IκBα protein （P<0.05， P<0.01）. ConclusionShuanghua drink effectively alleviates primary dysmenorrhea through analgesia and suppression of abnormal contractions of uterine smooth muscle. Its mechanism may be mediated by reduced levels of PGF_2α/PGE₂， TXB₂/6-keto-PGF_1α， iNOS， and NO， elevated β-EP level， and inhibited COX-2/NF-κB signaling pathway.

ObjectiveTo evaluate the efficacy of Shuanghua drink in treating primary dysmenorrhea in the rat model and explore its mechanism of action. MethodsAn oxytocin-induced writhing mouse model was established to evaluate the analgesic effect of Shuanghua drink. Forty-eight non-pregnant female institute of cancer research （ICR） mice were randomly divided into six groups， including a blank group， a model group， an ibuprofen group （85.00 mg·kg^-1）， a low-dose group of Shuanghua drink （7.14 mL·kg^-1）， a medium-dose group of Shuanghua drink （14.28 mL·kg^-1）， and a high-dose group of Shuanghua drink （28.57 mL·kg^-1）. Each group consisted of eight mice. All treatment groups received daily intragastric administration at corresponding doses for 10 consecutive days. One hour after the final administration， 2 U of oxytocin was intraperitoneally injected per mouse. The writhing latency and number of writhing within 20 minutes were recorded. A primary dysmenorrhea rat model was established by using estradiol benzoate and oxytocin to evaluate the inhibitory effect of Shuanghua drink on the contraction of uterine smooth muscle. Forty-eight non-pregnant female Sprague-Dawley （SD） rats were divided into six groups， including a blank group， a model group， an ibuprofen group （51.00 mg·kg^-1）， a low-dose group of Shuanghua drink （4.28 mL·kg^-1）， a medium-dose group of Shuanghua drink （8.57 mL·kg^-1）， and a high-dose group of Shuanghua drink （17.10 mL·kg^-1）. Each group consisted of eight rats. Rats received subcutaneous injections of estradiol benzoate for 10 consecutive days to enhance uterine sensitivity. On the eleventh day， oxytocin （2 U/rat） was intraperitoneally administered to induce abnormal uterine contractions for establishing the primary dysmenorrhea model. All treatment groups received daily intragastric administration from the second day of modeling for 10 days. The effects of Shuanghua drink were evaluated by using parameters including uterine motility and the variation rate of uterine motility. The mechanism of action was investigated in rats with primary dysmenorrhea. The content of prostaglandin F_2α （PGF_2α）， prostaglandin E₂ （PGE₂）， thromboxane B₂ （TXB₂）， prostacyclin metabolite （6-keto-PGF_1α）， and β-endorphin （β-EP） in uterine tissue of rats was detected by using enzyme-linked immunosorbent assay （ELISA）. The changes in the content of nitric oxide （NO） and inducible nitric oxide synthase （iNOS） were analyzed via colorimetric assay. Western blot was performed to determine the content of phosphorylated inhibitor of kappa B kinase beta （p-IKKβ）/IKKβ， phosphorylated inhibitor of kappa B alpha （p-IκBα）， IκBα， phosphorylated p65 （p-p65）， p65， and cyclooxygenase-2 （COX-2） proteins in uterine tissue of rats. ResultsIn the oxytocin-induced writhing mouse model， the model group exhibited significantly shortened writhing latency and increased writhing frequency compared to the control group （P<0.01）. Both the ibuprofen group and the high-dose group of Shuanghua drink displayed prolonged writhing latency （P<0.05）， while the ibuprofen group and the low-dose， medium-dose， and high-dose groups of Shuanghua drink exhibited reduced writhing frequency （P<0.01）. In the primary dysmenorrhea rat model， the uterine motility and its variation rate in the model group were significantly higher than those in the blank group （P<0.01）. These parameters were markedly suppressed by ibuprofen and Shuanghua drink at all tested doses （P<0.01）. For the mechanism of action， the model group showed significantly increased PGF_2α/PGE₂， TXB₂/6-keto-PGF_1α， NO， and iNOS in uterine tissue （P<0.05， P<0.01） and significantly decreased β-EP （P<0.01）. These parameters were significantly attenuated in the ibuprofen group and the low-dose， medium-dose， and high-dose groups of Shuanghua drink. The PGF_2α/PGE₂ （P<0.01）， TXB₂/6-keto-PGF_1α （P<0.01）， NO （medium-dose group P<0.05）， and iNOS （P<0.01） were reduced， and the β-EP （medium-dose group P<0.05） was up-regulated. Compared to the model group， the ibuprofen group and medium-dose group of Shuanghua drink showed significantly increased content of β-EP in the serum of rats （P<0.05）. Compared to the blank group， the model group showed significantly elevated expressions of COX-2， p-IKKβ/IKKβ， p-IκBα/IκBα， and p-p65/p65 proteins （P<0.01） and significantly reduced anti-inflammatory protein IκBα （P<0.05）. Compared to the model group， the ibuprofen group and the low-dose， medium-dose， and high-dose groups of Shuanghua drink showed significantly reduced expressions of COX-2 （P<0.01）， p-IKKβ/IKKβ （P<0.01）， p-IκBα/IκBα （P<0.05， P<0.01）， and p-p65/p65（P<0.01） and up-regulated expression of IκBα protein （P<0.05， P<0.01）. ConclusionShuanghua drink effectively alleviates primary dysmenorrhea through analgesia and suppression of abnormal contractions of uterine smooth muscle. Its mechanism may be mediated by reduced levels of PGF_2α/PGE₂， TXB₂/6-keto-PGF_1α， iNOS， and NO， elevated β-EP level， and inhibited COX-2/NF-κB signaling pathway.

Background/Aims: Systemic Inflammation (SI) is considered a key mechanism in disease progression and development of complications in decompensated liver cirrhosis. SI is mainly driven by portal hypertension and bacterial translocation. Transjugular intrahepatic portosystemic shunt (TIPS) insertion represents an effective treatment for portal hypertension. This study aims to investigate the impact of TIPS insertion on SI and bacterial translocation. Methods: We prospectively included 59 cirrhotic patients undergoing TIPS insertion. Blood samples were collected at TIPS insertion and follow-up (FU) 1, 3, 6, and 12 months thereafter. At all time points, we performed a comprehensive analysis of SI including 43 soluble inflammatory markers (SIMs), and surrogates of bacterial translocation (sCD14, sCD163). To investigate long-term kinetics of SI, C-reactive protein (CRP) and white blood cells (WBC) were retrospectively analyzed in a cohort of 177 patients up to 3 years after TIPS insertion. Results: At TIPS insertion, 30/43 SIMs, sCD14, and sCD163 measured significantly higher in cirrhotic patients compared to healthy controls. By FU6 25 SIMs and sCD14 measured at significantly lower levels compared to baseline. Interestingly, in patients with TIPS indication of refractory ascites, IL-6 decreased to levels documented in earlier stages of cirrhosis. In long-term follow-up, CRP levels significantly decreased after TIPS insertion, which translated into lower mortality in Cox regression analysis (HR 0.968, p=0.042). Notably, patients with residual ascites post-TIPS showed significantly higher CRP and IL-6 levels across all follow-ups compared to patients with resolved ascites. Conclusions Decreasing portal hypertension via TIPS insertion leads to a significant attenuation of SI and bacterial translocation over time.

Background/Aims: Systemic Inflammation (SI) is considered a key mechanism in disease progression and development of complications in decompensated liver cirrhosis. SI is mainly driven by portal hypertension and bacterial translocation. Transjugular intrahepatic portosystemic shunt (TIPS) insertion represents an effective treatment for portal hypertension. This study aims to investigate the impact of TIPS insertion on SI and bacterial translocation. Methods: We prospectively included 59 cirrhotic patients undergoing TIPS insertion. Blood samples were collected at TIPS insertion and follow-up (FU) 1, 3, 6, and 12 months thereafter. At all time points, we performed a comprehensive analysis of SI including 43 soluble inflammatory markers (SIMs), and surrogates of bacterial translocation (sCD14, sCD163). To investigate long-term kinetics of SI, C-reactive protein (CRP) and white blood cells (WBC) were retrospectively analyzed in a cohort of 177 patients up to 3 years after TIPS insertion. Results: At TIPS insertion, 30/43 SIMs, sCD14, and sCD163 measured significantly higher in cirrhotic patients compared to healthy controls. By FU6 25 SIMs and sCD14 measured at significantly lower levels compared to baseline. Interestingly, in patients with TIPS indication of refractory ascites, IL-6 decreased to levels documented in earlier stages of cirrhosis. In long-term follow-up, CRP levels significantly decreased after TIPS insertion, which translated into lower mortality in Cox regression analysis (HR 0.968, p=0.042). Notably, patients with residual ascites post-TIPS showed significantly higher CRP and IL-6 levels across all follow-ups compared to patients with resolved ascites. Conclusions Decreasing portal hypertension via TIPS insertion leads to a significant attenuation of SI and bacterial translocation over time.

Background/Aims: Systemic Inflammation (SI) is considered a key mechanism in disease progression and development of complications in decompensated liver cirrhosis. SI is mainly driven by portal hypertension and bacterial translocation. Transjugular intrahepatic portosystemic shunt (TIPS) insertion represents an effective treatment for portal hypertension. This study aims to investigate the impact of TIPS insertion on SI and bacterial translocation. Methods: We prospectively included 59 cirrhotic patients undergoing TIPS insertion. Blood samples were collected at TIPS insertion and follow-up (FU) 1, 3, 6, and 12 months thereafter. At all time points, we performed a comprehensive analysis of SI including 43 soluble inflammatory markers (SIMs), and surrogates of bacterial translocation (sCD14, sCD163). To investigate long-term kinetics of SI, C-reactive protein (CRP) and white blood cells (WBC) were retrospectively analyzed in a cohort of 177 patients up to 3 years after TIPS insertion. Results: At TIPS insertion, 30/43 SIMs, sCD14, and sCD163 measured significantly higher in cirrhotic patients compared to healthy controls. By FU6 25 SIMs and sCD14 measured at significantly lower levels compared to baseline. Interestingly, in patients with TIPS indication of refractory ascites, IL-6 decreased to levels documented in earlier stages of cirrhosis. In long-term follow-up, CRP levels significantly decreased after TIPS insertion, which translated into lower mortality in Cox regression analysis (HR 0.968, p=0.042). Notably, patients with residual ascites post-TIPS showed significantly higher CRP and IL-6 levels across all follow-ups compared to patients with resolved ascites. Conclusions Decreasing portal hypertension via TIPS insertion leads to a significant attenuation of SI and bacterial translocation over time.

OBJECTIVE To study the improvement effect and mechanism of Shengmai powder on heart failure （HF） mice with qi-yin deficiency. METHODS The mice were randomly divided into blank group （water）， model group （water）， Shengmai powder low-， medium-， and high-dose groups [2.61， 5.22 and 10.44 g/kg （based on crude drug dosage）] and positive control group （metoprolol， 30 mg/kg）， with 10 mice in each group. Except for the blank group， all other groups were subcutaneously injected with D-galactose， and a qi-yin deficiency HF mice model was established by continuous food restriction and weight-bearing swimming. At the same time of modeling， the corresponding medicine/water was gavaged once a day for five weeks. The general state of mice was recorded and the traditional Chinese medicine （TCM） syndrome score was evaluated. Behavioral experiments were conducted to investigate the total distance of open field action， the percentage of immobility time， and the swimming exhaustion time of mice. The contents of aspartate transaminase （AST）， creatine kinase （CK） and lactate dehydrogenase （LDH） in the serum of mice were detected； cardiac function indexes [heart rate， left ventricular ejection fraction （LVEF）， left ventricular end systolic diameter （LVESD）， left ventricular end diastolic diameter （LVEDD）， left ventricular mass index and whole heart mass index] were all detected； the histopathological morphology of mice myocardium was observed； the level of cardiomyocyte apoptosis in mice was detected； mRNA expression levels of B-cell lymphoma 2 （Bcl-2）， Bcl-2 associated X protein （Bax）， and Cleaved-caspase-3 in myocardial tissue of mice were detected； the phosphorylation levels of sarcoplasmic reticulum calcium regulatory related proteins [ryanodine receptor 2 （RyR2） and phospholamban （PLB）] in myocardial tissue of mice were detected. RESULTS Compared with the blank group， the body weight， total distance of open field action， swimming exhaustion time， LVEF， LVEDD， Bcl-2 mRNA expression level in myocardial tissue and PLB protein phosphorylation level in the model group were significantly reduced/shortened （P＜0.05）； TCM syndrome score， the percentage of immobility time， heart rate， LVESD， left ventricular mass index， whole heart mass index， cardiomyocyte apoptosis rate， the contents of CK， LDH and AST in serum， mRNA expression levels of Cleaved-caspase-3 and Bax and the phosphorylation level of RyR2 protein in myocardial tissue were significantly increased （P＜0.05）； there were inflammatory cell infiltration， disordered cell arrangement and obvious myocardial interstitial fibrosis in myocardial tissue. After the intervention of Shengmai powder， most of the above quantitative indexes in mice were significantly reversed （P＜0.05）， the inflammatory cell infiltration in myocardial tissue was reduced， and the degree of fibrosis was significantly reduced. CONCLUSIONS Shengmai powder can improve cardiac function， reduce the level of cardiomyocyte apoptosis and myocardial fibrosis in HF mice with qi-yin deficiency. Its mechanism may be related to the regulation of the expression of sarcoplasmic reticulum calcium regulation related proteins.

Objective To observe the efficacy and safety of Morinda officinalis oligosaccharides in the continuation treatment of mild and moderate depression.Methods An open,single-arm,multi-center design was adopted in our study.Adult patients with mild and moderate depression who had received acute treatment of Morinda officinalis oligosaccharides were enrolled and continue to receive Morinda officinalis oligosaccharides capsules for 24 weeks,the dose remained unchanged during continuation treatment.The remission rate,recurrence rate,recurrence time,and the change from baseline to endpoint of Hamilton Depression Scale(HAMD),Hamilton Anxiety Scale(HAMA),Clinical Global Impression-Severity(CGI-S)and Arizona Sexual Experience Scale(ASEX)were evaluated.The incidence of treatment-related adverse events was reported.Results The scores of HAMD-17 at baseline and after treatment were 6.60±1.87 and 5.85±4.18,scores of HAMA were 6.36±3.02 and 4.93±3.09,scores of CGI-S were 1.49±0.56 and 1.29±0.81,scores of ASEX were 15.92±4.72 and 15.57±5.26,with significant difference(P＜0.05).After continuation treatment,the remission rate was 54.59％(202 cases/370 cases),and the recurrence rate was 6.49％(24 cases/370 cases),the recurrence time was(64.67±42.47)days.The incidence of treatment-related adverse events was 15.35％(64 cases/417 cases).Conclusion Morinda officinalis oligosaccharides capsules can be effectively used for the continuation treatment of mild and moderate depression,and are well tolerated and safe.

Objective:To explore the clinical and electrophysiological characteristics of peripheral neuropathy in prediabetic patients.Methods:Subjects aged 20-65 years with high-risk factors of impaired glycemia enrolled in Beijing Tiantan Hospital, Capital Medical University from 2019 to 2022 were recruited to conduct oral glucose tolerance test, after excluding other causes of neuropathy or radiculopathy. Patients with impaired fasting glucose or impaired glucose tolerance were defined by American Diabetes Association criteria. These patients were divided into clinical polyneuropathy (PN) and clinical non-PN groups, according to the 2010 Toronto consensus criteria and the presence of PN symptoms and signs or not. Nerve conduction studies (NCS), F wave, sympathetic skin response (SSR), R-R interval variation (RRIV) and current perception thresholds (CPT) were performed and the abnormal rate was compared between different electrodiagnostic methods and between clinical subgroups.Results:Among the 73 prediabetic patients ultimately enrolled, only 20 (27.4%) can be diagnosed as clinical PN according to the Toronto consensus criteria. The abnormal rate of CPT (68.5%, 50/73) was significantly higher than those of F wave (2.7%, 2/73), lower limb NCS (0, 0/73), upper limb NCS changes of carpal tunnel syndrome (26.0%, 19/73), SSR (6.8%, 5/73) and RRIV (5.5%, 4/73; McNemar test, all P<0.001). With sinusoid-waveform current stimuli at frequencies of 2 000 Hz, 250 Hz and 5 Hz, the CPT device was used to measure cutaneous sensory thresholds of large myelinated, small myelinated and small unmyelinated sensory fibers respectively. CPT revealed a 21.9% (16/73) abnormal rate of unmyelinated C fiber in the hands of prediabetic patients, significantly higher than that of large myelinated Aβ fibers [8.2% (6/73), χ2=5.352, P=0.021]. Both abnormal rates of small myelinated Aδ [42.5% (31/73)] and unmyelinated C fibers [39.7% (29/73)] in the feet of prediabetic patients were significantly higher than that of large myelinated Aβ fibers [11.0% (8/73), χ2=18.508, 15.965, both P<0.001]. Compared with the clinical non-PN group, the abnormal rates of CPT [90.0% (18/20) vs 60.4% (32/53), χ2=5.904, P=0.015] and SSR [20.0% (4/20) vs 1.9% (1/53), P=0.016) were significantly higher in the clinical PN group. Conclusions:Peripheral neuropathies in prediabetic patients are usually asymptomatic or subclinical, and predispose to affect unmyelinated and small myelinated sensory fibers. Selective electrodiagnostic measurements of small fibers help to detect prediabetic neuropathies in the earliest stages of the disease.