Genomic structural variation is associated with hypoxia adaptation in high-altitude zokors.

Zokors, an Asiatic group of subterranean rodents, originated in lowlands and colonized high-elevational zones following the uplift of the Qinghai-Tibet plateau about 3.6 million years ago. Zokors live at high elevation in subterranean burrows and experience hypobaric hypoxia, including both hypoxia (low oxygen concentration) and hypercapnia (elevated partial pressure of CO2). Here we report a genomic analysis of six zokor species (genus Eospalax) with different elevational ranges to identify structural variants (deletions and inversions) that may have contributed to high-elevation adaptation. Based on an assembly of a chromosome-level genome of the high-elevation species, Eospalax baileyi, we identified 18 large inversions that distinguished this species from congeners native to lower elevations. Small-scale structural variants in the introns of EGLN1, HIF1A, HSF1 and SFTPD of E. baileyi were associated with the upregulated expression of those genes. A rearrangement on chromosome 1 was associated with altered chromatin accessibility, leading to modified gene expression profiles of key genes involved in the physiological response to hypoxia. Multigene families that underwent copy-number expansions in E. baileyi were enriched for autophagy, HIF1 signalling and immune response. E. baileyi show a significantly larger lung mass than those of other Eospalax species. These findings highlight the key role of structural variants underlying hypoxia adaptation of high-elevation species in Eospalax.

Study on repair of abdominal wall defect rats with hernia mesh coated with chitosan-based photosensitive hydrogel.

Herein, hydroxypropyl chitosan azide (AZ-HPCTS) was synthesized and prepared as a hydrogel coating applied to a polypropylene mesh (PPM) through UV irradiation. This study confirmed the hypothesis that hydrogels with porous three-dimensional network structures exhibited excellent biocompatibility and biodegradability and adhered well to PPM. During the 180-day follow-up period, the AZ-HPCTS-coated PPM (AH-PPM) promoted wound healing by promoting the secretion of transforming growth factor-beta1 (TGF-beta1) in the acute reaction stage, which was reduced to a lower level at 30 d. The PPM exhibited a lower fibrin lysozyme activity based on the expression of tissue plasminogen activator (tPA) compared with that of AH-PPM (P < 0.05). The intraperitoneal adhesion score of AH-PPM decreased to 2.4 at 180 d in contrast with PPM (P < 0.01), which remained at a high level throughout the study. In conclusion, the AZ-HPCTS hydrogel is a potential coating for hernia patches that deserves further study in the biomaterial field.

Functional thermosensitive hydrogels based on chitin as RIN-m5F cell carrier for the treatment of diabetes.

Herein, the thermosensitive hydroxypropyl chitin (HPCT) hydrogel was prepared and the chemical structures, microstructures, rheological properties and degradation in vitro were investigated. The HPCT hydrogel possessed satisfactory biocompatibility in mouse fibroblast cells and Sprague Dawley rats. On the other hand, N-acetylglucosamine (NAG) and carboxymethyl chitosan (CMCS) provided favorable capacity for promoting cell proliferation, delaying cell apoptosis, and facilitating the insulin secretion of rat pancreatic beta cells (RIN-m5F) in three-dimensional culture. Most importantly, the effects of HPCT/NAG and HPCT/CMCS thermosensitive hydrogels as RIN-m5F cells carriers were evaluated via injection into different areas of diabetic rats. Our results demonstrated that HPCT/NAG and HPCT/CMCS hydrogels loaded RIN-m5F cells could keep cells survival, maintain insulin secretion and reduce blood glucose for one week. Overall, the functional thermosensitive hydrogels based on HPCT were effective cell carriers for RIN-m5F cells and might provide novel strategy for the treatment of diabetes via cell engineering.