Functional constipation （FC） is a clinically common functional bowel disorder characterized by a protracted course and associations with various chronic disorders and psychological abnormalities. Although not life-threatening， FC significantly impairs patients' quality of life. FC subtypes include slow-transit constipation （STC）， defecatory disorder （DD）， and normal-transit constipation （NTC）. The pathological mechanisms underlying FC have not been fully elucidated， and overall clinical efficacy remains unsatisfactory. Animal models of FC serve as essential tools for the study of disease mechanisms and the development of novel therapeutics. This article systematically reviews the current state of research on the animal models of FC and identifies that rodents， particularly rats and mice， are the most commonly used species. Dogs and pigs are also employed in complex intervention studies due to their physiological similarities to humans， though their use is limited by housing challenges and ethical considerations. Induction methods vary across different FC subtypes. STC models are primarily established with chemical agents such as loperamide or compound diphenoxylate. DD modeling often involves low-fiber diets combined with methylene blue injection or rectal narrowing. NTC modeling mainly relies on low-fiber dietary interventions. In addition， disease-syndrome combination models based on traditional Chinese medicine （TCM） theory have been developed， encompassing excess patterns such as heat accumulation， cold accumulation， and Qi stagnation， as well as deficiency patterns including Qi deficiency， blood deficiency， Yin deficiency， and Yang deficiency. These are achieved through an approach of disease model + syndrome induction， enabling the integration of mechanisms from both Western and TCM perspectives. Models are evaluated from two aspects： disease and syndrome manifestations （e.g.， colonic transit， secretory function， and TCM syndrome indicators such as mental state and body weight） and disease mechanisms （e.g.， enteric nervous system， interstitial cells of Cajal， smooth muscle cells， gut microbiota， and metabolites）. However， current research still faces challenges such as poor consistency in some models， non-specific interference in mechanism interpretation， insufficient studies on NTC， and lack of TCM tongue and pulse diagnosis in evaluation. Future efforts should focus on optimizing model stability and specificity to provide a more reliable experimental basis for investigating the pathological mechanisms of FC and developing therapeutic agents.

Objective·To investigate the reference range for serum 25-hydroxyvitamin D in pregnant women in Shanghai. Methods·A total of 4969 healthy pregnant women in second trimester were enrolled, in whom there were 554 women aged over or equal to 35 years old and 4415 women aged under 35 years old. Meanwhile, 1048 non-pregnant women in child-bearing period were enrolled. The new born children had no complications of vitamin D deficiency such as rickets. The levels of 25-hydroxyvitamin D of all participants were detected by ELISA. The reference interval was defined as the central 95% range between the 2.5th and the 97.5th percentiles. Results·The 95% reference range for 25-hydroxyvitamin D levels showed a positive skewness distribution in second trimester pregnant women. The median of 25-hydroxyvitamin D levels was 36.8 nmol/L. The maximum was 108.6 nmol/L whereas the minimum was 11.8 nmol/L. The 95% reference range for 25-hydroxyvitamin D levels was from 15.9 nmol/L to 70.3 nmol/L. The median 25-hydroxyvitamin D was 36.6 nmol/L in women less than 35 years old, and 35.5 nmol/L in women aged over or equal to 35 years old. A significant difference was found between women aged under 35 years old and women aged over or equal to 35 years old (Z=-2.75, P<0.05). The median, maximum and minimum of 25-hydroxyvitamin D in non-pregnant women was 38.5 nmol/L, 110.5 nmol/L, 12.1 nmol/L, respectively, which were all higher than those in pregnant women (P<0.05). Conclusion·There was a lack of vitamin D in pregnant women in Shanghai, especially in pregnant women aged over or equal to 35 years old, despite the multivitamin supplements. However, no complications of vitamin D deficiency such as rickets were found in new born children. To determine the reference range of vitamin D in Shanghai is helpful for pregnancy women in taking vitamin supplement, especially important in preventing maternal and fetal complications caused by vitamin D deficiency.