Histomorphometric Adaptations of Superior and Inferior Vena Cavae after Moderate Intensity Continuous Exercise - A Preclinical Trial

Abstract

Objective: This study was aimed at evaluation of effects of Moderate Intensity Continuous Training(MICT) on the histomorphometric parameters of superior vena cava (SVC) and inferior vena cava(IVC) in Sprague Dawley rats. Methods: Twenty-four male healthy Sprague Dawley rats were randomly divided into two groups.Group A (n=12) was assigned to the Moderate Intensity Continuous Training whereas Group B (n=12)was the control group with no exercise. The exercise intervention was workout on treadmill at 70%Maximal exercise intensity for 22-24 mins for 5 consecutive days/week for four weeks. The animalswere sacrificed after completion of exercise protocol for histomorphometry of the Inferior Vena Cavaand Superior Vena Cava. H&E stained slides were examined under Nikon Ts2R-FL inverted micro-scope and images were taken. Images were analyzed and morphometry was performed by using Im-age J software. Luminal area, wall thickness and wall to lumen ratio were evaluated. Statisticalanalysis was performed on SPSS version 23. Results: Histomorphometric evaluation of the luminal area, wall thickness and wall to lumen ratio ofboth large veins showed statistically significant difference between control and the exercise groups.The luminal area, wall thickness and wall to lumen ratio of the IVC was significantly increased in theexercise group with p values 0.003, 0.04 and <0.001 respectively. There was statistically significant in-crease in luminal area and wall thickness of SVC in the exercise group (p<0.0001) and (p = 0.0001),whereas wall to lumen ratio was found to be reduced significantly p<0.001. Conclusion: Our study has revealed that moderate intensity continuous exercise of four weeks duration has profound effects on the histomorphometry of superior and inferior vena cava. The findings ofour study highlight that the venous morphological adaptations to meet the heightened demands generated after moderate intensity continuous exercise are as prevalent as cardiac and arterial adapta-tions