Neuroprotective Treatments for Digestive Forms of Chagas Disease in Experimental Models: A Systematic Review

Table 1

Summary of the main data regarding interventions with neuroprotective potential in experimental models of the digestive form of Chagas disease.

Intervention

Experimental model

Evaluated groups and number of animals used

Strain

Route of infection/inoculum used

Phases

Chronic phase induction method

Treatment schedule

Intervention concentration of/treatment route

Mortality rate

Organ and region evaluated

Methodology used for neuronal analysis/analyzed region

Number of fields and neurons analyzed

Number of neurons per group

Neuronal body area per group (μm^2 or cm^2)

Area of neuronal cytoplasm per group (μm^2)

Neuronal nucleus area per group (μm^2)

Reference

Cyclophosphamide (CY)

Calomys callosus

Not infected (NI) (5); Infected without treatment (IC) (5); Infected treated with cy (IC-cy) (5)

MORC-1

Intraperitoneal

Chronic

Natural time of infection

3 consecutive days

0.2 mL of a 0.4 mg/mL solution of the drug in water/orally

Not informed

Distal esophagus

Cresyl violet staining myenteric plexus

Performed in the total area between the inner and outer muscles of the esophagus

NI: IC: IC-cy:

NI:  μm^2; IC:  μm^2; IC-cy:  μm^2

Unvalued

Unvalued

[22]

Lycopodium clavatum 13c (Ly)

Rattus norvegicus, Wistar lineage

IC (); Infected treated with Ly (IC-Ly) ()

Y

Intraperitoneal

125 days (acute phase) 322 days (chronic phase)

Natural time of infection

2 days before infection and on days 2, 5, and 8 postinfection

10 μL/mL water ad libitum

Not informed

Intestine proximal (PC) and distal (DC) colon

GIEMSA staining myenteric plexus

120 fields for neuron quantification; 300 neurons for cell body, cytoplasm, and nucleus measurement

IC PC 125 days: IC PC 322 days: IC-Ly PC 125 days: IC-Ly PC 322 days: IC DC 125 days: IC DC 322 days: IC-Ly DC 125 days: IC-Ly DC 322 days:

IC PC 125 days: IC PC 322 days: IC-Ly PC 125 days: IC-Ly PC 322 days: IC DC 125 days: IC DC 322 days: IC-Ly DC 125 days: IC-Ly DC 322 days:

IC PC 125 days: IC PC 322 days: IC-Ly PC 125 days: IC-Ly PC 322 days: IC DC 125 days: IC DC 322 days: IC-Ly DC 125 days: IC-Ly DC 322 days:

IC PC 125 days: IC PC 322 days: IC-Ly PC 125 days: IC-Ly PC 322 days: IC DC 125 days: IC DC 322 days: IC-Ly DC 125 days: IC-Ly; DC 322 days:

[20]

Acetylsalicylic acid (ASA)

Swiss mice (Mus musculus)

NI (); NI treated with ASA (NIASA) (); IC (); IC treated with ASA (ICASA) ()

Y

Intraperitoneal 1.300

81 days (chronic phase)

Six doses of benznidazole (Lafepe, PE, Brazil; 100 mg/kg) were administered by oral gavage 11, 13, 15, 25, 29, and 48 days after infection

Intraperitoneal consecutive days (55-63 days postinfection) and on days 65, 67, 69, 71, 73, and 75 postinfection

100 μL ASA of stock solution (50 mg/kg) via not informed

Not informed

Intestine distal colon

GIEMSA staining myenteric plexus

120 neuron quantification fields; 300 neurons for cell body, cytoplasm, and nucleus measurement

NI: NI-ASA: IC: IC-ASA:

NI: 132.6 (96.3; 182.7); NI-ASA: 209.7 (163.7; 311.3); IC: 114.6 (82.0; 156.5); IC-ASA: 159.8 (119.0; 227.2)

NI: 75.4 (50.3; 111.6); NI-ASA: 132.0 (91.3; 227.7); IC: 65.0 (43.2; 97.8); IC-ASA: 98.2 (65.5; 153.2)

NI: 54.5 (40.3; 68.6); NI-ASA: 68.6 (52.3; 87.4); IC: 46.8 (35.4; 61.0); IC-ASA: 57.3 (43.2; 77.6)

[27]

Cyclophosphamide (cy)

Calomys callosus

IC (); Infected treated with cy (IC-cy) ()

MORC-1

Intraperitoneal 100.000

10 days (acute phase) 450 days (chronic phase)

Natural time of infection

Acute phase: cyclophosphamide in water from day of infection to 21 postinfection; Chronic phase: 0.4 mg/mL cyclophosphamide in water 10 days before euthanasia (440 days)

Intraperitoneal acute phase: 0.2 mg/mL of Genuxal; Chronic phase: 0.4 mg/mL of Genuxal

Not informed

Distal annular esophagus segments

Cresyl violet staining myenteric plexus

Total neurons count in total area between inner and outer muscle layer

IC 10 days: 23; IC 450 days: 12.6; IC-cy 10 days: 18; IC-cy 450 days: 22

IC 10 days: IC 450 days: IC-cy 10 days: IC-cy 450 days:

Unvalued

Unvalued

[23]

Acetylsalicylic acid (ASA)

Swiss mice (Mus musculus)

NI (); NI treated with ASA (NIASA) (); IC (); IC treated with ASA (ICASA) ()

Y

Intraperitoneal 1.300

75 days (chronic phase)

Six doses of benznidazole (Lafepe, PE, Brazil; 100 mg/kg) were administered by oral gavage 11, 13, 15, 25, 29, and 48 days after infection

Treatment performed intraperitoneally daily from the 5th to the 11th day after infection

20 mg/kg

Not informed

Esophagus distal part

Nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-dp) staining myenteric plexus

100 neuron quantification fields; 100 neurons for cell body, cytoplasm, and nucleus measurement

NI: NI-ASA: IC: IC-ASA:

NI: NI-ASA: IC: IC-ASA:

NI: NI-ASA: IC: IC-ASA:

NI: NI-ASA: IC: IC-ASA:

[24]

Acetylsalicylic acid (ASA)

Swiss mice (Mus musculus)

NI (); NI treated with ASA (NIASA) (); IC (); IC treated with ASA (ICASA) ()

Y

Intraperitoneal 1.300

75 days (chronic phase)

Six doses of benznidazole (Lafepe, PE, Brazil; 100 mg/kg) were administered by oral gavage 11, 13, 15, 25, 29, and 48 days after infection

Intraperitoneal consecutive days (55-63 days postinfection) and on days 65, 67, 69, 71, 73, and 75 postinfection

50 mg/kg

Not informed

Esophagus distal part

Nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-dp) staining myenteric plexus

100 neuron quantification fields; 100 neurons for cell body, cytoplasm, and nucleus measurement

NI: NI-ASA: IC: IC-ASA:

NI: NI-ASA: IC: IC-ASA:

NI: NI-ASA: IC: IC-ASA:

NI: NI-ASA: IC: IC-ASA:

[25]

Ácido acetilsalicílico (ASA)

Swiss mice (Mus musculus)

NI; IC NI treated with ASA in the acute phase; (NIaASA) IC treated with ASA in the acute phase (ICaASA); NI treated with ASA in the chronic phase (NIcASA); IC treated with ASA in the chronic phase

Y

Intraperitoneal 1.300

75 days (chronic phase)

Six doses of benznidazole (Lafepe, PE, Brazil; 100 mg/kg) were administered by oral gavage 11, 13, 15, 25, 29, and 48 days after infection

Acute phase: treatment performed intraperitoneally daily from the 5th to the 11th day after infection; Chronic phase: treatment performed intraperitoneally daily from the 55th to the 63rd day after infection. Then alternate treatment from day 65 to day 75

Acute phase: 20 mg/kg; Chronic phase: 50 mg/kg

No deaths reported in any group

Intestine colon

Immunofluorescence for nNOS, VIP, SP, and myosin-V/myenteric plexus

35 fields for quantification of neurons for each marker; 300 neurons for area measurement for each marker

Myosin-V: NI: IC: NIa-ASA: ICa-ASA: NIc-ASA: ICc-ASA: nNOS: NI: IC: NIa-ASA: ICa-ASA: NIc-ASA: ICc-ASA: VIP: NI: IC: NIa-ASA: ICa-ASA: NIc-ASA: ICc-ASA:

Myosin-V: NI: IC: NIa-AAS: ICa-ASA: NIc-ASA: ICc-ASA: nNOS: NI: IC: NIa-ASA: ICa-ASA: NIc-ASA: ICc-ASA: VIP: NI: IC: NIa-ASA: ICa-ASA: NIc-ASA: ICc-ASA:

Unvalued

Unvalued

[26]

Cyclophosphamide (cy)

Calomys callosus

IC (); Infected treated with cy (IC-cy) ()

MORC-1

Intraperitoneal 100.000

10 days (acute phase) 450 days (chronic phase)

Natural time of infection

Acute phase: cyclophosphamide in water from day of infection to 21 postinfection; Chronic phase: 0.4 mg/mL cyclophosphamide in water 10 days before euthanasia (440 days)

Intraperitoneal acute phase: 0.2 mg/mL of Genuxal; Chronic phase: 0.4 mg/mL of Genuxal

Not informed

Colon

Coloração por; Cresyl violet staining; Myenteric plexus

Contagem total neurons in the total area between the inner and outer muscle layer

IC 10 days: 20.3; IC 450 days: 5.2; IC-cy 10 days: 14; IC-cy 450 days: 13.5

IC 10 days: IC 450 days: IC-cy 10 days: IC-cy 450 days:

Unvalued

Unvalued

[21]