Growth of the lower spleen pole remaining after subtotal splenectomy in rats

Study of the upper pole after subtotal splenectomy in rats

PURPOSE

To evaluate macro/microscopic viability of the upper pole (UP) in rats after 80 days of subtotal splenectomy preserving the upper pole (SSPUP).

METHODS

Twenty-five male Wistar rats were submitted to SSPUP. After 80 days, the rats were euthanized, and the remaining UP was evaluated macroscopically regarding appearance, color, consistency, length, width, thickness, and presence of fibrosis/necrosis; and microscopically regarding presence of red and white pulp, fibrosis/necrosis.

RESULTS

Two rats died during surgery and were removed from the statistical analysis. There was statistically significant increase in length and width between the pre and postoperative in the experimental group, with no significant difference in thickness. In the manipulation group, the macroscopic appearance of the spleen was normal in pre and postoperative, with viability preserved. In the experimental group, two UP of the spleen were not found during the second surgery. Macroscopically, it was observed absence of fibrosis and necrosis in all cases. Microscopically, the white and red pulp were intact in both groups. Two spleens of rats in the manipulation group presented areas with fibrosis and necrosis focus, which were not enough to be considered inviable.

CONCLUSIONS

The UP of the spleen remained viable in 91.3% of the cases.

Macro and microscopic comparison of the upper pole of the spleen with the lower pole in partial splenectomy

Purpose

To evaluate the viability of the upper (UP) and lower pole (LP) of the spleen from a macro and microscopic point of view, after subtotal splenectomy with preservation (SSP) of the UP and the LP.

Methods

Seventeen male Wistar rats, two months old, were submitted to SSPUP and SSPLP and 5 to simulated operation (SG). After 80 days, the rats were euthanized, and the remaining LP and UP and intact spleens were evaluated macroscopically and microscopically.

Results

Two rats died during the operation. Macroscopic analysis showed that in 15 LP, one of them was not viable and in 15 UP and in 5 spleens in the SG, all were viable. In the statistical analysis, there was no difference in relation to viability. The LP and UP analyzed showed variation. As for the length, the UP increased significantly; however, in relation to the width, there was a significant increase in the LP in relation to the UP. In addition, the weight of the UP was significantly greater than that of the LP. Microscopic analysis attested viability of the splenic remnants.

Conclusion

There was no significant difference regarding the viability of UP and LP, in macroscopy and microscopy.

Micronucleus test in peripheral blood of rats treated with hyperbaric oxygen after subtotal splenectomy preserving the lower pole

PURPOSE

To assess the mutagenic potential of the oxygen inhalation therapy (HBO), by means of the micronucleus test, performed in peripheral blood of rats that underwent subtotal splenectomy with lower pole preservation (ESTPI), after HBO sessions or simulations.

METHODS

Eighteen male Wistar rats, were distributed into three groups of six animals: group 1 - submitted to ESTPI and HBO sessions; group 2 - submitted to ESTPI and HBO simulations; group 3 - underwent cyclophosphamide administration. In groups 1 and 2, blood samples from the animals' tails were collected before surgery (T0) and immediately after the 13th HBO session or simulation (T1). In group 3, tail blood samples were collected from animals before (T0) and 24 hours after (T1) cyclophosphamide (CP) delivery. The number of micronucleated normochromatic erythrocytes (MNNCE) was determined by blind counting 2000 normochromatic erythrocytes (NCE) per animal.

RESULTS

Micronuclei average after CP delivery in group 3 was higher than before its use, thus confirming the mutagenic activity of this drug (p=0.01). In groups 1 and 2, no significant difference in the average of Micronuclei was observed when comparing it to blood samples before and after the 13th HBO session or simulation.

CONCLUSION

The treatment protocol used in this study did not induce Micronucleus formation in animals submitted to ESTPI and HBO treatment or simulation.

Effect of hyperbaric oxygen therapy in rats with subtotal splenectomy preserving the inferior pole

PURPOSE: To evaluate the effect of hyperbaric oxygen therapy on the survival and weight of rats submitted to subtotal splenectomy and on the viability and growth of the inferior pole. METHODS: Forty Wistar rats underwent subtotal splenectomy with preservation of the inferior pole and distributed into two groups: Group A (n=20) - not treated with hyperbaric oxygen, Group B (n=20) - treated with hyperbaric oxygen. These groups were divided into two subgroups of 10 animals each, according to the time of euthanasia, 15th and 45th days. The survival and weight of the animals were recorded. The inferior pole was measured, weighed and morphologically analyzed. RESULTS: All animals survived. The weight of the animals increased in all subgroups, but decreased on the 10th day in the subgroups treated with hyperbaric oxygen (p<0.001). The viability of the inferior pole was more evident in animals treated on the 15th day, but did not differ on the 45th day. The growth of the inferior pole has not occurred on the 15th day but on the 45th day after surgery in untreated animals (p<0.01) and treated animals (p<0.05). Vascular and cellular increase in treated animals was significantly higher than in untreated ones. CONCLUSION: Hyperbaric oxygen therapy did not affect the survival of animals but reduced their weight. It improved the viability of the inferior splenic pole, but did not interfere with their growth.

Subtotal laparoscopic splenectomy in rats with preservation of the inferior pole

Purpose: To evaluate the feasibility and safety of subtotal splenectomy by laparoscopy with inferior pole preservation and to determine the viability of the splenic remnant. Methods: Twenty male Wistar rats weighing between 365 g and 474 g (mean 417.92 ± 36.15g SD) were operated and randomly assigned to two groups : Group 1 rats were killed on postoperative day 10 (n = 10), and Group 2 on the postoperative day 80 (n = 10). Both the inferior splenic pole and the superior part of the spleen, which was used as a control to measure inferior pole viability, were weighed and morphologically examined. Results: The technique was feasible in all cases. There were two postoperative deaths on immediate postoperative and one not well defined. The average weight percentage of the inferior pole, measured indirectly on the 10th day, was 53.67% ± 11.59% and on the 80th day was 62.69% ± 6.89%. The inferior pole was necrotic, with abscess formation in one case (5.9%) and appeared normal in all other cases. Microscopy showed features that were compatible with normality. Conclusions: Subtotal splenectomy with preservation of the inferior pole by laparoscopy was feasible and safety. The lower splenic pole was viable in 94.1% of animals.