Physicochemical and Cytological Analysis of Synovial Fluid in Young and Adult Dogs

Abstract

Background: Synovial fluid is a complex viscous fluid which provides lubrication to the articulating joints to avoid friction and wearing of cartilages. It is also an indicator of health status of joint, but a comparison of its composition between young and adult dogs is lacking. Methods: Present study was conducted to evaluate physical, biochemical and cytological analysis of synovial fluid in apparently healthy stifle joint of young and adult non-descript dogs. Twelve non-descript dogs irrespective of sex were divided into two groups (6 dogs in each group) i.e., group I (2-8 months of age) and group II (1-8 years of age). Dogs died in the OPDs of Veterinary Clinical Complex, Jabalpur were acquired with the consent of pet parent. The duration of study was one year, i.e., from September 2021 to August 2022. Immediately after collection of synovial fluid; volume, colour, viscosity, pH, specific gravity and refractive index were recorded, smear on slides were prepared. Protein and glucose were estimated within one hour using biochemical semi-autoanalyzer. Result: Volume of fluid collected in a single attempt varied from one drop to 0.5 ml. Mean pH values in group I and II were 7.33±0.17 and 7.67±0.25 respectively. Mean values of refractive index and specific gravity were 1.34 and 1.02 respectively in both the groups. Observations of mucin clot test of synovial fluid in group I and II exhibited a tight ropy clot in a clear solution. Turbidity was not observed in any case. Mean protein concentration was 1.29±0.18 g/dl and 2.74±0.84 g/dl in group I and II respectively. The concentration of glucose in group I and II was 102.79±3.66 mg/dl and 105.47±4.19 mg/dl respectively, that was around normal blood plasma level. Cytological observation revealed 1-3 cells per field at 1000x magnification. Mean neutrophil count in both the groups was about 6% of total nucleated cell count. Small mononuclear cells and large mononuclear cells were 19±3.79, 74.33±4.24 and 12.17±2.33, 81.83±2.54 in group I and II respectively. Biochemically and cytologically no significant difference was observed between the group I and II. Vacuolated large mononuclear cells contributed about 6-6.5% of total large mononuclear cells in both the groups. No significant difference was observed in most physical and biochemical parameters of synovial fluid in young and adult dogs, except a higher concentration of protein content in adults.