Study of blood count in the validity experimental appendicitis in rabbits

ESTUDO DO HEMOGRAMA NA VIGÊNCIA DE APENDICITE EXPERIMENTAL EM COELHOS

STUDY OF BLOOD COUNT IN THE VALIDITY EXPERIMENTAL APPENDICITIS IN RABBITS¹

Eduardo Chibeni Fernandes Ramos²

Antonio Mauro Vieira³

Félix Carlos Ocariz Bazzano⁴

Luiz Roberto Nascimento⁵

Neil Ferreira Novo⁶

Virginio Cândido Tosta de Souza⁷

Yara Juliano⁸

Ramos ECF, Vieira AM, Bazzano FCO, Nascimento LR, Novo NF, Souza VCT, Juliano Y. Study of blood count in the validity of experimental appendicitis in rabbits. Acta Cir Bras [serial online] 1999 Apr Jun; 14(2). Available from: URL: http://www.scielo.br/acb.

SUMMARY: A group of thirty six rabbits was studied, with weight ranging from 2400 to 3100 grams, in order to evaluate the blood test on the validity of experimental acute appendicitis. In order to do that, the animals were distributed amony three groups of 12 rabbits each, that corresponded to observation periods of 24 hours(Group A), 48 hours(Group B) and 72 hours(Group C). The presence of macroscopic appendicitis was verified in all the rabbits of the experiment on the three studied periods. The blood test study showed statistic significance when reading the values of haemoglobin, haematocrit and monocytes in Group C; of total and segmented leucocytes, eosinophiles, limphocytes and monocytes in Group B; when the groups faced each other, however, there was no estatistic significance. So, it was concluded that the values of haemoglobin, red blood, white cells and haematocrit are not suitable markers for experimental appendicitis in rabbits.

SUBJECT HEADINGS: Blood cell count. Appendicitis. Rabbits. Experimental.

INTRODUCTION

Acute appendicitis is one of the diseases more frequently approached since its diagnosis misleads the most trianed physicians^{15,16,19,21,29,34,35}.

Since 1895 studies have been carried out to produce experimental appendicitis²⁷.

Although mortality rate is low, this disease is a challenge for physicians almost based only on the clinical findings.

In 1996, evaluation of the effects of the ligature of the appendix vermiformis basis of the rabbit, performed by BAZZANO, led us to decide to investigate blood count in provoked apendicitis in face of a complete occlusion of the appendix vermiformis of the rabbit⁴.

METHOD

Thirty-six white New Zealand rabbits weighing from 2400 and 3100 grams were used. The animals were divided into three groups of 12 rabbits receiving the denomination of Groups A, B and C.

The animals were put in individual cages seven days previously to the experiment, receiving a commercial ration specially for the specimens and water.

On the day of the experiment the animals received only water. They were intramuscularly anesthetized with acepromazine, xylazine and katamine.

The animal was in decubito dorsalis on the surgical table. After shearing of the auricula sinistra and antisepsis with iodopovidona solution, the extension was performed with exposure through the regio dorsalis of the arteria auricularis sinistra and, blood sample was collected for laboratory analysis.

Through the median laparotomy preceded by shearing of the regio abdominis caudalis, the cecum and appendix vermiformis were located and ligature of its basis was performed, as proclaimed by BAZZANO in his study⁴.

After the observation period programmed for each group(Group A-24 hours; Group B-48 hours and Group C-72 hours) the animals were anesthetized using the same procedure of the beginning of the experiment. After anesthesia, a new blood sample of the animal was collected. Next, the animals were submitted to an euthanasia and, opening of the cavum abdominis was then performed and macroscopic alterations in the appendix vermiformis of all animals of the experiment were observed.

Blood samples collected for hematological analysis were forwarded to the laboratory. The compact volume of red blood cells was determined by the microhematocrit method. Hemoglobin was spectrophotometerly measured. The count of red blood and white cells were performed using an automatic cell counter. Differential counts for leukocytes were computed by the method in a glass slide.

For analysis of the results, non-parametric tests were applied considering the nature of the variables studied or variability of the measurements. Wilcoxon Test and Variance Analysis by Kruskal-Wallis rank were performed. In all tests 0,05 or 5% was fixed for level of null rejection, signaling with na asterisk the significant values.

RESULTS

DISCUSSION

Appendicitis is a disease with several clinical presentations and may develop to irreversible disorders up to death if the process is not identified and, its evolution not interrupted by an appendicectomy. Several diseases have signs and symptoms suggesting appendicitis.

In spite of the developments in the medical diagnosis, presently there is no laboratory, radiological tests (or combination of them) or complementary procedure with enough sensibility of effectively diagnose appendicitis in the preoperative period.

In the experimental area, few investigators are concerned in trying to investigate from one model the indicative parameters of the apendicular process.

Anthropoid monkeys have appendix vermiformis similar to human being^11.32. In these animals which died in bondage, the evidence of spontaneous appendicitis was demonstrated³⁰.

Thus, dogs and rabbits are used in experimental studies. Due to not secreting mucus as rabbits, monkeys and men do, the appendix vermiformis of the dog is considered not suitable for this type of research^30,31.

With the reports of spontaneous appendicitis in 1903, the rabbit is considered the ideal since this animal is easy to be obtained for experimental studies²³.

The use of rabbits in biomedical studies is frequent but still limited for experimental procedures in the surgical area since its postoperative alterations are not known⁸.

In spite of the difficulties found for the rabbits, attempts must be done in order to use this animal in surgical procedures due to the following advantages: easy manipulation, docile animals, no need of large spaces for lodging and easy control of diseases^14,24. Rabbits are animals of facile recovering from the effects of anesthetic agents and with an adequate physical shape for many experimental surgical procedures remarkably those needing study of the organs²⁴.

Hematological parameters were determined for the different periods of the day with no variation in the reading of the blood of white, New Zealand rabbits¹³. In order to avoid alterations, the collect of the material was performed in the same period of the day¹³.

The values of comprehensible data on the blood constituents (elements) found in the experiment with white, New Zealand rabbits were compared with the results known and catalogued as normal¹⁰.

Confirming the normal parameters in the reading of the erythrocytes of the rabbits^7,8,18,33, by means of ligature of appendix vermiformis basis, appendicitis was then provoked on these animals⁴ and a slight decrease in the number was observed in the observation periods of 24 hours (group A), 48 hours (group B) and 72 hours (group C).

After the provoked appendicitis in rabbits, the percentage of hematocrit showed a decrease in the three groups of the experiment.

Hemoglobin measurements led us to verify the occurrence of a decrease in the Group C concentration.

In the differential counts of the white blood cells, the semented presented a decrease in the count in all the groups with predominance of the Group B, this result followed by the eosinophils.

Regarding lymphocytes, Group A also presented a decrease after provoking appendicitis but in the Groups B and C an increase in the count was observed.

When analyzing monocytes, the counting was increased in all the experiment groups with predominance in the Groups B and C.

Statistical analysis did not show significance in the experiment.

In the investigated literature, no other studies was found regarding the existing alterations in the reading of blood count in rabbits with appendicitis provoked by the ligature of the appendix vermiformis basis.

CONCLUSION

Hemoglobin, red and white blood cells and hematocrit values found in this study are not sufficient to characterize experimental appendicitis in rabbits.

REFERENCES

1. Adrian C. Die appendicitis als folge einer allgemeinerkrankung. Klinischer und Experimentelles. Mitt Grenzgeb Med Chir 1901; 7:407-16.

2. Bain JÁ, Spoerel WE. A streamlined anaesthesic system. Can Anaesthesiol Soc J 1972; 19:426-35.

3. Baum J. Clinical applications of low flow and closed circuit anaesthesia. Acta Anaesthesiol Belg 1990; 41:239-47.

4. Bazzano FCO. Avaliação dos efeitos da ligadura da base do appendix vermiformis do coelho [dissertação]. São Paulo: Escola Paulista de Medicina - Universidade Federal de São Paulo; 1996.

5. Beaussenat M. Appendicites experimentales. Patogenia de l’appendicite thesis. 1897. p.2-34.

6. Bjellin L, Carter AM. Circulatory adjustaments to pregnancy in the rabbit. Biol Reprod; 16:112-6.

7. Bjotvedt G. Common diseases of New Zealand white rabbit. Vet Med Small Anim Clin 1982; 77:1259-66.

8. Bortolotti A, Castelli D, Bonati M. Hematology and serum chemistry values of adult, pregnat and newborn New Zealand Rabbits (Oryculasus Cuniculus). Lab Anim Sci; 39:437-9..

9. Bree M, Cohen B. Effects of urethane anaesthesia on blood vessels in rabbits. Lab Anim Care; 15:254-9.

10. Burns KF, Lannoy CW. Compendium of normal blood values of laboratory animals, with indication of variations. Toxicol Appl Pharmacol; 8:429-37.

11. Christeller E, Mayer E. Wurmfortsatzentzundung (appendizitis). In:¾ Handbuch der Speziellen Pathologischen Anatomie und Histologie. Berlin: Springer; 1929. p 469-74.

12. Flecknell PA. Anaesthesia of animals for biomedical research. Br J Anaesth 1993; 71:885-94.

13. Fox RR, Laird CW. Diurnal variations in rabbits: hematological parameters. Am J Phisiol 1970; 218:1609-12.

14. Gardner AF. The development of general anaesthesia in the albino rabbit for surgical procedures. Lab Anim Care 1964; 14:214-25.

15. Gilmore OJA, Browett JP, Griffin PH. Appendicitis and mimicking conditions: a prospective study. Br J Surg 1974; 61:281.

16. Graham JM, Pokorny WJ, Harberg FJ. Acute appendicitis in preschool age children. Am J Surg 1980; 139:247.

17. Hewitt CD, Innes DJ, Savory J, Wills MR. Normal biochemical and hematological values in New Zealand white rabbits. Clin Chem 1989; 35(8):1777-9.

18. Kabata J, Gratwhol A, Tichelli A, John L, Speck B. Hematologic values of New Zealand white rabbits determined by automated flow cytometry. Lab Anim Sci 1991; 41:613-9.

19. Kazariam KK, Roeder WJ, Marsheimer W. Decreasing montality and increasing morbidity from acute appendicitis. Am J Surg 1970; 119:681.

20. Laird CW, Fox RR, Mitchell BP, Blau EM, Schultz H. Effect of strain and age on some hematological parameters in the rabbit. Am J Phisiol 1970; 218(6)1613-7.

21. Marchildon NB, Dudgeon DL. Perforated appendicitis current experience in a children’s hospital. Ann Surg 1977; 185-4.

22. Massone F. Anestesiologia veterinária: farmacologia e técnicas. Rio de Janeiro: Editora Guanabara S.A.; 1988.

23. Mori M. Spontane appendicitis bei cinigen tierspecies. Mitr Grenzgeb Med Chir 1903; 12:639.

24. Murdock HR. Anesthesia in the rabbit. Fed Proc 1969; 28:1510-6.

25. Ng LF, Zuzel M, Born GVR. Changes in the concentration of leucocytes and platelets in the peripheral blood during sterile inflammation in rabbits. Br J Exp Pathol 1977; 58:200-8.

26. Purvis GM, Sewel MMH. Leucocyte counts in normal young rabbit Br Vet J 1973; 129:42-51.

27. Roux P. Appendicite experimentale. Cong Fran Chir 1895; 8:213.

28. Siegel S. Estadistica no paramétrica. México: Ed. Trillas; 1975.

29. Talbert JL, Zuidema GD. Appendicitis: a reapraisal of and old problem. Surg Clin North Am 1966; 46:1101.

30. Wangensteen OH, Bowers WF. An experimental study of the significance of the obstructive factor is the genesis of acute appendicitis. Arch Surg 1937; 34:496-502.

31. Wangensteen OH, Dennis C. Experimental proof of the obstructive origin of appendicitis in man. Ann Surg 1939; 110(4):629-42.

32. Wangensteen OH, Dennis C. The production of experimental appendicitis(with rupture) in higher apes by luminal obstruction. Surg Gynecol Obstet 1940; 70:799-806.

33. Wechsler SJ. Blood collection techniques and normal values for ferrets, rabbits and rodents a review. Vet Med Small Anim Clin; 78:713-7.

34. White JJ. Surgical emergencies in infancy and childhood. Surg Clin North Am 1970; 50:877.

35. Yoshida Y, Yoshida K. The high rate of appendicectomy in Japan. Med Care 1976; 14:950.

Ramos ECF, Vieira AM, Bazzano FCO, Nascimento LR, Novo NF, Souza VCT, Juliano Y. Estudo do hemograma na vigência de apendicite experimental em coelhos. Acta Cir Bras [serial online] 1999 Apr Jun; 14(2). Available from: URL: http://www.scielo.br/acb.

RESUMO - A comparação de resultados de exames laboratoriais de coelhos hígidos e coelhos com apendicite provocada, tem como objetivo procurar um marcador para o diagnóstico desta patologia. Foram estudados 36 coelhos com peso corporal variando de 2400 a 3100 gramas, distribuído em três grupos de 12 coelhos, que correspondem aos períodos de observação de 24 horas(Grupo A), 48 horas(Grupo B) e 72 horas(Grupo C). Verificou-se a presença de apendicite macroscópica em todos os coelhos do experimento, nos três grupos estudados. O estudo dos hemogramas mostrou alterações nas leituras dos valores de leucócitos totais, segmentados, eosinófilos, linfócitos e monócitos no Grupo B; da hemoglobina, hematócrito e monócitos no Grupo C; no entanto, quando se confrontam os resultados entre os grupos não há significância estatística. Conclui-se que os valores da hemoglobina, glóbulos vermelhos, glóbulos brancos e hematócrito não são marcadores adequados para apendicite experimental em coelhos.

DESCRITORES - Contagem de células sanguíneas. Apendicite. Coelhos. Experimental.

Address for correspondence:

Eduardo Chibeni Fernandes Ramos

Av. Francisca Ricardina de Paula, 80

37550-000 Pouso Alegre – MG

Data do recebimento: 11/03/99

Data da revisão: 11/04/99

Data da aprovação: 06/05/99

¹

Summary of Master Thesis approved in the Post Graduation Course in Technical Surgery and Experimental Surgery of the UNIFESP-EPM - Federal University of São Paulo - Paulista School of Medicine, SP, Brazil, oriented by the Professor Doctor (PhD) Virginio Cândido Tosta de Souza.

²

Master in Surgical Technique and Experimental Surgery of the UNIFESP-EPM and Professor in charge of the Discipline of Basis of the Surgical Technique - Faculty of Medicine of Pouso Alegre-MG

³

Doctor in Medicine of the UNIFESP-EPM - Associate Professor of the Departament of Surgical Clinic and Professor in charge of the Discipline of Pharmacology - Faculty of Medicine of Pouso Alegre-MG

⁴

Master in Surgical Technique and Experimental Surgery of the UNIFESP-EPM and Associate Professor of the Maternal Infantile Departament - Faculty of Medicine of Pouso Alegre-MG

⁵

Master in Surgical Technique end Experimental Surgery of the UNIFESP-EPM

⁶

Professor of the Biostatistics Division of the Departament of Preventive Medicine of the NIFESP-EPM

⁷

Doctor in Medicine of the UNIFESP-EPM and Full Professor of the Departament of Surgical Clinic - Faculty of Medicine of Pouso Alegre-MG

⁸

Professor of Biostatistics Divison of the Departament of Preventive Medicine of the UNIFESP-EPM

Publication Dates

• Publication in this collection
  16 July 1999
• Date of issue
  Apr 1999

History

• Received
  11 Mar 1999
• Reviewed
  11 Apr 1999
• Accepted
  06 May 1999