Effects of maternal ischemic preconditioning in the colon of newborn rats submitted to hypoxia-reoxygenation insult

Comparative evaluation of the osteogenic capacity of human mesenchymal stem cells from bone marrow and umbilical cord tissue

Mesenchymal stem cells (MSCs) have been extensively investigated in the field of regenerative medicine. Human bone MSCs (BMSCs) have become a common type of seed cell for bone tissue engineering. However, the viability and cell number of BMSCs are negatively correlated with donor age, and as the extraction process is painful, this method has not been widely used. As human umbilical cord MSCs (UCMSCs) may be harvested inexpensively and inexhaustibly, the present study evaluated and compared the regenerative potential of UCMSCs and BMSCs to determine whether UCMSCs may be used as a novel cell type for bone regeneration. In the present study, the proliferation and osteogenic capacity of BMSCs and UCMSCs was compared in vitro. BMSCs and UCMSCs were respectively combined with biofunctionalized macroporous calcium phosphate cement, and their bone regenerative potentials were determined by investigating their capacity for ectopic bone formation in a nude mouse model as well as their efficacy in a rat model of tibia bone defect. The extent of bone regeneration was examined by X-ray, histological and immunohistochemical analyses. The results revealed that UCMSCs exhibited a good osteogenic differentiation potential, similarly to that of BMSCs, and that UCMSCs were able to contribute to the regeneration of bone and blood vessels. Furthermore, no significant differences were identified between BMSCs and UCMSCs in terms of their bone regenerative effect.

Neonatal necrotizing enterocolitis rat model attenuated by a remote ischemic preconditioning in the pregnant

Purpose:

To evaluate the effect of remote ischemic preconditioning (r-IPC) administered to pregnant rats, in the ileum of newborn rats subjected to hypoxia and reoxygenation.

Methods:

We used three pregnant rats and their newborn rats distributed in three groups: 1) Control (C) - Newborn rats born from a pregnant rat which did not undergo any intervention; 2) Hypoxia-Reoxygenation (H/R) - Newborn rats born from a pregnant rat which did not undergo any intervention, and were subjected to hypoxia-reoxygenation; 3) Remote Ischemic Preconditioning (r-IPC) - newborn rats born from a pregnant rat which was subjected to remote ischemic preconditioning twenty-four hours before giving birth and the newborn rats were subjected to hypoxia-reoxygenation. Segments of ileum were prepared for histological analysis by HE and immunohistochemistry by the Ki67 to evaluate cell proliferation, crypt depth and villus height and evaluation of apoptosis by cleaved caspase-3.

Results:

The intensity of the lesions was lower in the r-IPC than in the H/R group, showing significant difference (p<0.01). The r-IPC group showed a higher proliferative activity compared to the H/R group (p<0.01), with deeper crypts (r-IPC > H/R - p < 0.05), and higher villi, showing significant difference (r-IPC > H/R - (p <0.01). The occurrence of apoptosis in the H/R group was lower in comparison to groups C and r-IPC, with significant difference (H/R < r-IPC; p<0.05).

Conclusion:

The remote ischemic preconditioning applied to the pregnant rat protected the ileum of newborn rats subjected to hypoxia and reoxygenation, with decreased intensity of the lesions in the ileum mucosa and preservation of proliferative activity, keeping the villus height and crypt depth similar to group C.

Remote ischemic preconditioning and tacrolimus in the fetal small bowel transplant in mice

PURPOSE:

To evaluate the effect of remote ischemic preconditioning (IPC-R) in the fetal small bowel transplantation model.

METHODS:

Two groups were constituted: The Isogenic transplant (ISO, C57BL/6 mice, n=24) and the allogenic transplant (ALO, BALB/c mice, n=24). In each group, the animals were distributed with and without IPC-R. It was obtained the following subgroups: Tx, IPC-R, Fk, IPC-Fk, in both strains. Intestinal grafts were stained with hematoxylin and eosin and immunohistochemically.

RESULTS:

The graft development evaluation in ISO group showed that IPC-R reduced the development compared with ISO-Tx (5.2±0.4 vs 9.0±0.8) and IPC-R-Fk increased the graft development compared with IPC-R (11.2±0.7 and 10.2±0.8). In ALO group, IPC-Fk increased the development compared with ALO-Tx and ALO with IPC-R (6.0±0.8, 9.0±1.2, 0.0±0.0, 0.5±0.3). The PCNA expression was increased in ISO group treated with Fk and IPC-R compared to other groups (12.2±0.8 vs Tx: 8.8±0.9, IPC-R: 8.0±0.4 and Fk: 9.0±0.6). The graft rejection was lower in groups treated with IPC-R (-18%), Fk (-68%) or both (-61%) compared with ALO-Tx.

CONCLUSION:

Remote ischemic preconditioning showed benefic effect even associate with Tacrolimus on the development and acute rejection of the fetal small bowel graft in the Isogenic and Allogenic transplants.